Wednesday, December 3, 2008

2008 Season Summary

This season there were seventeen depressions, 16 of which became named storms, from which 8 became hurricanes, and 5 major hurricanes. Nearly a thousand deaths and $44 billion worth of damage resulted from the above average season. In total, 1 storm formed in May, 3 in July, 4 in August, 4 in September, 3 storms and 1 depression in October, and 1 storm in November.

Hurricane Bertha was the longest lived pre-August storm ever recorded.
2008 was the third costliest (wealth adjusted for 2008) year on record and the fourth busiest (most storms) on record.
Also, 2008 is the only season in which a major hurricane formed in every month from July-November.
Haiti was hit with four consecutive storms (Fay, Gustav, Hanna, and Ike)
Tropical Storm Marco was the smallest tropical cyclone in the entire world with a tropical storm force wind span of only 10 miles.

Overall, the 2008 season was very notable and more active seasons will be ahead.

Sunday, November 30, 2008

Hurricane Paloma (2008)

Storm Active: November 5-10

A system in the extreme southern Caribbean Sea slowly strengthened and organized on November 3. On November 5, the system became Tropical Depression Seventeen. After skirting the coast of Central America, the system became Tropical Storm Paloma, the fourth "P" storm ever used in the Atlantic. By the evening of the next day, October 6, the system had become the eighth hurricane this season. Hurricane Paloma continued to move generally northward and strengthen until passing over the Caymen Islands as a Category 4 hurricane. Shortly after, Hurricane Paloma reached its peak intensity of 145 mph and a pressure of 940 millibars making it the second strongest November storm on record in the Atlantic. On November 8, after weakening to a Category 3, Paloma made landfall in Cuba. It rapidly weakened into a tropical storm the next day and by late November 10, the system had become a low. The low survived for three more days before dissipating in the Gulf of Mexico on November 13.

Image not available. For an image, see here.

Tropical Depression Sixteen (2008)

Storm Active: October 14-16

A slow moving tropical system developed on October 13. On the next day it became Tropical Depression Sixteen. It moved slowly along the coast of Nicaragua and quickly reached its peak intensity of 30 mph and a pressure of 1006 millibars. The system was forecasted to become a tropical storm but all too quickly the storm became disorganized and soon made landfall, losing all chance for any redevelopment. The system dissipated on October 18. However, although the system was weak, it did cause flooding and $9.7 million dollars of damage and at least 16 were killed.



Sixteen shortly after developing. The system never had a definite center and the disorganization is evident.



Track of Sixteen.

Saturday, November 15, 2008

Hurricane Omar (2008)

Storm Active: October 13-18

Around October 10, a tropical disturbance moved off the South American border of the Caribbean Sea and moved into more favorable waters. Upper level winds died down enough for the system to develop into Tropical Depression 15, with 35 mph winds. The next day, October 14, the system reached tropical storm strength and was named Tropical Storm Omar. Meanwhile, Omar was making a loop in the Caribbean, and eventually made an odd turn towards the north-east (this particular turn in that area is uncommon in general but common in October and November). That same evening, after rapidly intensifying, the system became a Category 1 hurricane. As the system approached Puerto Rico and the Virgin Islands the system reached its peak intensity. Its peak intensity was reached on October 16, when it was a Category 4 hurricane with 135 mph winds and a minimum central pressure of 958 millibars. After passing these small islands, Omar rapidly weakened. By October 18, the system was a tropical storm and by later that day, the system had become a remnant low. The remnants of Omar tracked northward before being absorbed by an exxtratropical cyclone on October 20.



Omar as a Category 1 hurricane in the Caribbean Sea.



Track of Omar from October 10 to October 18.

Tropical Storm Nana (2008)

Storm Active: October 12-14

A weak tropical wave that had moved off the west coast of Africa a few days earlier slowly developed, and on October 12, a weak Tropical Storm Nana formed at its peak intensity of only 40 mph winds and pressure of 1005 millibars. Strong west-to-east shear destroyed the eastern half of Nana, and by October 14, it had weakened into a remnant low. Any remnant of the system disappeared within the next day. Nana caused no damage to any land mass and no damage resulted.



Nana at minimal tropical storm status. The lopsidedness of the system soon ended its life.

Wednesday, November 5, 2008

Tropical Storm Marco (2008)

Storm Active: October 6-8

A weak low-pressure system formed south of Cuba on October 3. The system interacted with the Yucatan Peninsula and weakened. Finally, on October 6, the low-pressure emerged into the extreme southern Bay of Campeche, nearly over land. Later that day, a small Tropical Depression Thirteen formed. That night, the system was declared Tropical Storm Marco. By this time, Marco became the smallest tropical cyclone ever recorded throughout the entire world. Its tropical storm force winds only extended a mere 10 miles from the center, greatly surpassing the 30 mile record set by Tropical Cyclone Tracy in 1974. Marco pulled away from land slightly and strengthened to its peak intensity of 65 mph winds and a pressure of 998 millibars. then, on October 7, the system made landfall in Veracruz, and it became the smallest tropical cyclone ever to make landfall. By early the next day, Marco dissipated over the mountains of Central Mexico.



Marco at peak intensity. Note the size in comparison to the surrounding country of Mexico.

Tuesday, November 4, 2008

Tropical Storm Laura (2008)

Storm Active: September 29-October 1

During the last week of September a strong extratropical low tracked south-west from the cold north Atlantic. The system slowly gained tropical characteristics and by September 29, it was organized enough to be called Subtropical Storm Laura. As it continued to move westward, it met warmer waters and developed further. On September 30, Laura was reclassified as a tropical storm. By this time, it had turned to the north, and it briefly reached its peak intensity of 60 mph winds and a pressure of 994 millibars. On the first day of October, it lost tropical characteristics without directly affecting land. A few days later, Norway experienced winds and rain from the system. Soon after it dissipated.



Laura at peak intensity. Note "non-tropicalness" of system.

Friday, October 10, 2008

Hurricane Kyle (2008)

Storm Active: September 25-29

A tropical wave moving west through the northern Caribbean developed into Tropical Storm Kyle on September 25. Because of a stationary front off the Atlantic coast, Kyle was turned northward. Due to strong west to east sheer, Kyle's convection stayed away from the right side of the system. After being hindered by Hispaniola, the system was free of land, and therefore rapidly strengthened into Hurricane Kyle on the 27. Kyle then briefly reached its peak intensity of 80 mph and a pressure of 994 millibars. Soon, Kyle accelerated northward before making landfall in Nova Scotia as an extratropical storm on the 29.



Hurricane Kyle. Note the lopsidedness of the convection.



Track of Kyle.

Thursday, October 2, 2008

Tropical Storm Josephine (2008)

Storm Active: September 2-6

As August ended, a tropical wave moved off the coast of Africa and developed. On September 2, the disturbance was upgraded to Tropical Depression Ten. Josephine briefly exhibited an unusually organized system (see below) but it disappeared shortly after as the system transformed. The system's peak intensity (65 mph winds and pressure of 994 millibars was reached when there was almost nothing left of the system in terms of convection. After a brief redevelopment, Josephine was ripped apart by a high-pressure system to the north. Soon after, Josephine became a remnant low. The system was monitored and for over a week the remnants tracked generally west, nut on September 14, Josephine finally dissipated over the Bahamas. No major effects resulted from this system.



Josephine at peak intensity. Note the lack on cloud activity around the center of circulation.



Track of Josephine.



Image of Josephine briefly showing major hurricane-like strength. Note its similarity in appearance to a southern hemisphere cyclone.

Tuesday, September 2, 2008

Hurricane Ike (2008)

Strom Active: September 1-14

In late August, a tropical wave moved off the coast of Africa. On September 1, it became Tropical Depression Nine. It started to rapidly strengthen and by September 4, it had already reached it s peak intensity of 145 mph winds and a pressure of 935 millibars. It continued on a more northerly track so it did not have any major effects in Puerto Rico or the Leeward Islands. A high-pressure system to the north of Ike not only steered to more southward but also weakened the system and soon it was only a Category 2. It did regenerate before landfall back to a weak Category 4 hurricane with 135 mph winds. Then, as a strong Category 3 it made its first landfall in western Cuba. Interaction with land weakened the system and when it made landfall in Cuba again, it was only a Category 1. Ike reentered the Gulf of Mexico on September 9. Over the next day it strengthened back to a Category 2. The wind field of Ike expanded rapidly and became abnormally large, with tropical storm force winds extending 275 mph out form the center and hurricane force winds 120 mph fro the center. The system reached 110 mph winds before landfall but the hurricane force winds were so widespread that the storm surge was resembled that of a Category 4. Ike made landfall before sunrise on September 13. The system weakened over land and quickly became a depression and turned north-east. It left a trail of destruction up through western New England before finally dissipating. 147 deaths resulted from Ike, almost half of them in the United States. Also, Ike was the third costliest hurricane on record in the U.S. behind Andrew and Katrina.



Ike at peak intensity over the warm Atlantic waters.



Track of Ike.

Sunday, August 31, 2008

Hurricane Hanna (2008)

Storm Active: August 28-September 6

During the last week of August a tropical wave moved off Africa. By August 28, it was strong enough to be called Tropical Depression Eight. The next day Eight was upgraded to Tropical Storm Hanna. The storm tracked west-north-westward until it was stopped by a front and it slowly drifted south-west into the Turks. Hanna couldn't strengthen because of the more powerful Hurricane Gustav's intake of moist air. Also, strong shear whipped in from the north. But soon, these effects lessened and by midday on September 1, Hanna had become a hurricane with 80 mph winds and a pressure of 983 millibars. Hanna was weakened by shear over the next day into a tropical storm but started to turn northwest and by September 5 was moving at 20 mph, approaching the coast of the Carolinas. Overnight it made landfall and weakened to 65 mph winds. Then, it accelerated past New England and sped off the coast into extratropical waters. Hanna caused 529 deaths in Haiti along with 8 in the U.S.

Hurricane Gustav (2008)

Storm Active: August 25-September 2

On August 25, a wave in the south-east Caribbean became Tropical Depression Seven. A mere three hours later, the Depression became Tropical Storm Gustav. It continued to develop and became a Category 1 hurricane with 90 mph winds shortly before make landfall in south-west Haiti. The system was strong, but the circulation was relatively tight, and hurricane force winds were not widespread. It quickly weakened to a tropical storm and turned west while the eye was still over land and emerged on the 27th. It only had 45 mph winds and was very weak as it hit Jamaica but still caused major flooding. Over the 85 degree waters of the north Caribbean it intensified into a hurricane within half a day. By noon on August 30, Gustav had become the second major hurricane of the season. It had 145 mph sustained winds in the eyewall and had doubled in size as it hit the Isle of Youth, Cuba. It made landfall in mainland Cuba with 150 mph winds and an internal pressure of 941 millibars. It weakened as it emerged into the Gulf, but probably will gain strength as it approaches Louisiana. Gustav picked up speed before landfall and hit south-east Louisiana as a Category 2 hurricane with 110 mph winds at 11 o'clock Eastern Time, September 1. Even over land Gustav remained organized and convection continued to flare up around the center and it slowly weakened and moved north-west. It weakened to a low on September 4 and dissipated the next day. In total Gustav caused $20 billion in damage and 125 deaths, 25 of them being in the United States.



Gustav shortly after landfall.



Track of Gustav.

Friday, August 22, 2008

Tropical Storm Fay (2008)

Storm Active: August 15-25

On August 7, a strong tropical wave moved off Africa. Over the next few days, it fluctuated in strength and on August 15, the tropical wave finally became Tropical Sotrm Fay with 40 mph winds and a pressure of 1006 mb. It made landfall in the Dominician Republic and then Cuba as it moved steadily west-north-west. Then,it turned north and hit the Florida Keys on August 18. Less then a day later Fay slammed into Florida with 60 mph winds and a pressure of 998 mb. Fay reached its peak intensity of 65 mph and a pressure of 986 mb over Florida on August 19. The next day, Fay emerged into the Atlantic Ocean with 45 mph winds. Fay strengthened back to 60 mph before drifting westward into Florida once again. Soon after it made it seventh and final landfall (a record fourth landfall in Florida) and continued north-east. Flooding was recorded from Fay up into New England over the next few days.



Fay at peak intensity over south-central Florida.



Track of Fay.

Monday, August 4, 2008

Tropical Storm Edouard (2008)

Storm Duration: August 3- 6

A tropical wave formed in the north Gulf of Mexico on August 2. It intensified the next day into Tropical Depression Five, a and shortly after, Tropical Storm Edouard. Tropical Storm Edouard currently has winds of 45 mph and a pressure of 1002 millibars as it drifts slowly west towards Texas. Over the next day, Edouard gained strength and by early August 5, it had 65 mph winds and a pressure of 997 millibars as it was making landfall. It made landfall soon after and weakened quickly. It was totally gone by August 6. No major damage resulted from this storm.



Tropical Storm Edouard approaching Texas.

Monday, July 28, 2008

Basins Where Tropical Cyclones Form

Basically, tropical cyclones form all over the world. They form in the north Atlantic, the North-east Pacific, the North-west Pacific, the South-east Pacific (including Australia), the South Indian. and the North Indian Ocean. Although many cyclones (over 30% of the total) many also form elsewhere. In addition,in the Atlantic and north-east Pacific they are called hurricanes, in the north-west Pacific they are called Typhoons, and in all other basins they are simply referred to as cyclones.



Click on image to enlarge it.

All tropical cyclones in the world from 1985-2005. Note the lone tropical cyclone in the South Atlantic in the time period. This had the strength of a Category 2 hurricane at landfall. It was named Cyclone Catarina because it made landfall in close proximity to Santa Catarina, Brazil. It caused approximately 5 fatalities and $400,000,000 worth of damage (wealth adjusted for 2008.)
Image from Wikipedia.

Monday, July 21, 2008

Hurricane Dolly (2008)

Storm Active: July 20-25

Around July 13, a tropical wave formed just east of the Winward islands and tracked slowly through the Caribbean. It was named Tropical Storm Dolly on July 20. Over the next day it crossed the Yucatan pennisula and emerged in the Gulf of Mexico. Dolly intensified rapidly on July 22 and by noon, had 70 mph winds and a minimum pressure of 991 millibars. Dolly kept being upgraded and by noon, Dolly was a Category 2 hurricane with 100 mph winds and a pressure of 964 millibars. By this time, heavy rain along with tropical storm force winds were over parts of Texas and Mexico. Soon after, Dolly made landfall. Over ten inches of rain were dumped locally over the next three days, but eventually, Dolly dissipated. Dolly had caused twenty deaths and $1.5 billion in damage.




Dolly at peak intensity before reaching landfall.




Track of Dolly.

Sunday, July 20, 2008

Tropical Storm Cristobal (2008)

Storm Duration: July 18-23

On July 15, a wave organized west of Florida. But before it had time to develop, it crossed over Florida. It emerged and organized on July 17. Then, very late on July 18, the wave became Tropical Depression Three with 30 mph winds and a pressure of 1009 millibars. On July 19, Tropical Depression Three became Tropical Storm Cristobal just off the coast of Charleston. Shortly after, it became Tropical Storm Cristobal with 45 mph winds and a pressure of 1005 millibars. Cristobal's strength fluctuated over the next few days and stedily moved off the coast but it quickly weakened and became extratropical on July 23.

All times are in Eastern standard time.



Tropical Depression Three shortly before being named.



Track of Cristobal.

Friday, July 4, 2008

Hurricane Bertha (2008)

Storm Active: July 3-20

As July began, a tropical wave moved of the coast of Africa. Unlike many other systems of this region, the circulation remained intact. The wave continued to develop and on July 2, became Tropical Depression Two, with sustained winds of 35 mph and a pressure of 1008 millibars. Then, on the morning of July 3, Tropical Storm Bertha formed. Bertha's winds increased for the first time late on July 3 to 45 mph and the pressure dropped to 1002 millibars. Early on July 4, the track of Bertha shifted to the west, putting the storm closer to Bermuda in a week or so. Then the winds increased to 50 mph, where they would stay for awhile, as Bertha started moving more directly west. Then, during the evening of July 6, Bertha strengthened again into a storm with 60 mph winds and an internal pressure of 998 millibars. Bertha's track now puts it directly into Bermuda. On July 7, Bertha became a hurricane with 75 mph winds and a pressure of 994 millibars. Bertha is now bearing down on Bermuda. Then, Bertha rapidly intensified to a major hurricane and by early July 8, Bertha had reached its peak intensity of 120 mph and a pressure of 952 millibars. After that point, Bertha started to weaken. Also, Bertha turned northward. Then, on July 9, Bertha was downgraded and it only retained minimal hurricane status with 75 mph winds. Overnight, Bertha unexpectedly strengthened to a Category 2 hurricane with 105 mph winds and a pressure of 975 millibars. Also. the track shifted once again putting Bermuda back in danger by Sunday or Monday. Bertha currently has winds of 85 mph. Then over the next few days, Bertha stayed at minimal hurricane status. On July 13, bertha finally weakened to a tropical storm and on July 14 Bertha finally hit Bermuda with 30+ mph sustained winds and gusts above 40. By july 15, Bertha was moving off Bermuda. But a extratropical low moving south-west stopped Bertha and forced in briefly southward. Soon after, Bertha briefly became a minimal hurricane before weakening and becoming extratropical over Iceland.



Bertha as a major hurricane in the central Atlantic.



Track of Hurricane Bertha.

Thursday, July 3, 2008

Typical Hurricane Tracks

In June, systems can form only in a tight region about the Gulf of Mexico and up the east coast.  Near Africa, water is too cold for development.



By July, storms can form farther east in the Atlantic. The Gulf of Mexico, and north of the Caribbean are two hot spots for development.



By August, a tropical system can pop out of nowhere and become a hurricane the next day. Formation has spread to the Eastern most Atlantic and powerful storms are always a possibility in the east Caribbean. Systems are steered in the U.S.A. more often and less turn east than the later season.



The peak of the Hurricane season has come. Except for the extreme north-east, storms can form anywhere in the Atlantic. The official peak of activity is September 11. After this point the hurricane season starts to decline.



In October, temperatures of the east Atlantic drop below favorable for hurricanes. Activity can still be found in the Caribbean, but is much more common north of that area, including the Gulf of Mexico. Powerful major hurricanes are uncommon from this point on.



From November to the new year, Caribbean storms are almost non-existent. The cooling waters hinder almost all development. Most, if not all storms form and dissipate in the open waters way off the coast of the U.S.


All photos provided by National Hurricane Center.

Sunday, June 29, 2008

The Dagger of Death

During June 2008, many tropical waves moved off the coast of Africa. But, in the Caribbean Sea, a phenomenon occurred, hindering tropical development. This is called the "Dagger of Death" by hurricane experts. The reason behind this is that low-level winds (winds around 10,000 feet above sea level or so) are moving the opposite way that upper level winds (winds at about 36,000 feet) were moving at the same location. Therefore, when a storm system passes through the Caribbean Sea, the clouds that extend into both these layers are ripped apart, leaving the system decapitated.

Saturday, May 31, 2008

Tropical Storm Arthur (2008)

Storm Active: May 31-June 2

On May 31, the remnant of a tropical storm in the Pacific (Tropical Storm Alma) crossed over into the Gulf of Honduras.  A few miles off of the coast of Belize, it became Tropical Storm Arthur.  During the afternoon of May 31, Arthur slammed into Belize with winds at 40 mph and internal pressure at 1005 millibars. Somehow, coming in to early June 1, Arthur managed to maintain minimal tropical storm status, with the internal pressure rising to 1006 millibars. The system continued to track slowly west over the Yucatan. It finally weakened and dissipated on June 2 over Central America.

All times are in Eastern Standard Time.




Image of Tropical Storm Arthur near peak intensity over the Yucatan Peninsula.


Track map of Arthur.

Monday, May 26, 2008

Hurricane Names List

For the Atlantic in 2008, the name list is

Arthur (used)
Bertha (used)
Cristobal (used)
Dolly (used)
Edouard used)
Fay (used)
Gustav (used)
Hanna (used)
Ike (used)
Josephine (used)
Kyle (used)
Laura (used)
Marco (used)
Nana (used)
Omar (used)
Paloma (used)
Rene
Sally
Teddy
Vicky
Wilfred

This list is the same as the 2002 list except Isidore and Lili are replaced by Ike and Laura respectively.

Wednesday, May 21, 2008

Sizes and Structures of Black Holes

There are four main sizes of black holes: micro, stellar-mass, intermediate, and supermassive. Micro black holes can only weigh up to the mass of the moon, and all are less then a 1/10 of a millimeter in diameter. These are results of colliding cosmic waves or even bombardment of particles in particle accelerator. Stellar-mass holes are formed by collapsed giant stars (info on collapsed stars here, and giant stars here). These black holes are typically under 10 solar masses and are about 30 km across. The next type, intermediate black holes, are formed when one black hole is swallowed by another, enlarging it. These black holes weigh up to a thousand suns! Finally, supermassive black holes are found at the centers of galaxies. These black holes began as quasars and weigh from 100,000 to a billion suns. These black holes are so large that the largest, if placed in the sun's position, would extend out to the orbit of Earth!!!!

Black holes have three main parts to them. The first and outermost is called the ergosphere. This only exists if the black hole has angular momentum (see types of black holes) . In this zone, it is impossible for any object to stand still. The spin of the black hole causes a tidal force that acts upon the gravity well, shifting it. The ergosphere is in the shape of an elongated sphere that is tangent to the outer event horizon. The outer event horizon is the point of no return. Nothing, not even light can escape once beyond this point. Since no light is emitted from this part of the black hole, nothing inside can be seen. But it is believed that inside, at the very center, is the singularity. The singularity is the star's core crushed to a point (or the case of a spinning black hole, a ring) so small that it must be magnified over a trillion times to view any structure. More on black holes here and here.

Tuesday, May 20, 2008

Types of Black Holes

Black Holes are the result of collapsed stars that are more than approximately 4 solar masses. Although stars, planets, moons, galaxies etc. all have thousands of distinguishing characteristics, black holes only have three (this was a theory entitled "Black Holes Have No Hair" created by John Wheeler).

The three characteristics are: mass, charge and angular momentum (the last is related to spin). A Schwartzschild black hole is a black hole with only mass, and neither of the other two characteristics. These black holes have an even gravitational well and a gravitational singularity shaped as a dot. Also, these black holes are perfectly spherical, and have a fixed event horizon radius. However, these holes are rare, and usually black holes are much more complex. More info on black holes can be found here, here and here.

Thursday, May 15, 2008

Variable Stars

Variable stars are stars that undergo significant changes in magnitude. About 50,000 of these have been discovered, and they are separated into two main groups. One type only appears to change in luminosity because it is eclipsed by another star in a binary system. Even planets have created optical variables by passing in front of stars.

Real variable stars actually swell and shrink. Usually, variable stars have periods that repeat over and over. In a lot of cases, these periods are a few days or weeks. But some have periods that last years, and they may increase or decrease by over 10 magnitudes. Others don't even have a period at all. These stars are very unstable (like stars in the process of a nova) and some explode without warning. Yet other variable stars are eruptive. Many of these are giants and supergiants, which flare easily because of unstable outer layers. Flare stars like these may brighten by two magnitudes in seconds, and then be gone just as fast.

Globular and Open Clusters

Along with multiple star systems, there are also larger groups of stars called star clusters. Star clusters are divided into two main groups: globular clusters and open clusters. Globular clusters form in the halos of galaxies (areas outside the visible parts of galaxies), and consist of very old stars compared to the ones near the center. They may have hundreds of thousands of stars, all of which are gravitationally bound together, and orbiting the galaxy as a single satellite. Globular clusters are also very dense, and most of their mass usually is packed tightly in the center of the cluster.

Open clusters, however, are totally different. They don't form in all galaxies, and consist of very young stars. They are formed by a giant molecular cloud (see the formation of the solar system) that is way too big for one star. The upper limit of members in these clusters is only a few thousand. Unlike globular clusters, open clusters are very loosely gravitationally bound. They orbit near the center of a galaxy, and any interactions between them and other objects may scramble them. But even if they aren't disturbed, they always break up after a few hundred million years.

Friday, May 9, 2008

Types of Stars: Giants and Dwarfs

Stars come in a variety of sizes, temperatures and luminosities. The biggest stars are supergiants and hypergiants. These heavy stars fuse heavier elements than the ordinary Hydrogen and Helium. Although these stars have the hottest cores, their outer edges are very cool (the lowest only about 2000 K), and they also are the least luminous. The largest star on record is the star VY Canis Majoris. It is a hypergiant has a diameter 1800 times that of the Sun! In comparison, if the Sun was replaced with VY Canis Majoris, its outer edges would extend past the orbit of Saturn. Giants are always red or orange. These stars burn their fusion supply so quickly, that they only live for about 10 million years sometimes.

Other stars of this faint luminosity include: white dwarfs, brown dwarfs and black dwarfs (same as white dwarfs but totally cooled off). A brown dwarf is a special case of star where the temperature doesn't get high enough to start Hydrogen fusion, but high enough to do either deuterium (Hydrogen with a neutron and a proton) fusion (lower limit for this fusion is 13 Jupiter masses), or Lithium fusion (lower limit 65 Jupiter masses). These stars also have extremely long lives. They can live for trillions (not billions, trillions) of years!!!!!

Monday, May 5, 2008

Multiple Star Systems

As everyone knows, moons orbit around planets, and planets orbit around stars. But what if, in a developing solar system two clumps of matter form instead of one (information on formation of planetary systems shown here)? When two or more stars begin Hydrogen fusion close enough to each other to have a gravitational link, a multiple star system is born. Being near the Sun, most humans would think that binary or larger star systems are a rare occurrence. But in reality, most stars have a partner. Star systems are separated into two main categories, optical star systems, and physical star systems. An optical star system is present when two stars are right next to each other in the sky, but in distance, they may as well be thousands of light-years apart.

Physical star systems are when stars are actually orbiting one another. However, a star system is only truly binary if the center of gravity lies between the two stars. An example of a binary system (but not star system), is the relation between Pluto and Charon. Since Charon is about half the mass of Pluto, they both orbit around a point just outside Pluto's surface. Otherwise, in these systems are planet-moon systems. But sometimes three or more stars orbit each other. Most large star systems consist of a close binary relationship and a lighter single or binary pair orbiting farther out. The record for physical star systems is six stars. Three pairs of binaries make up this system. Sometimes, one star turns into a black hole (here, here, here and here) and the other loses gas to it, resulting in a nova.

Friday, May 2, 2008

Solar Wind

The Sun gives of waves of charged particles, called plasma.  These waves begin at incredible speeds, causing a "ring" to form around the solar system.  The Galactic Cosmic Rays generated by the magnetic field of the Milky Way itself, cannot cross into this ring because the output of the Sun's solar wind is so strong.  Galactic Cosmic Rays consist of interstellar medium (the particles that simply float freely in space, mostly Hydrogen and Helium).  The border between where solar wind stops is called the Heliopause.  Inside this boundary is called the Heliosphere.  The point where the solar wind slows to subsonic (under the speed of sound) speeds is called the Termination Shock.  On the other end, the place where Galactic Rays fall below sonic speeds is called the Bow Shock.  Relative to other solar system objects, the Kuiper Belt lies on the edge of the Heliosphere, while the Oort Cloud lies outside it.  The Heliopause is at about 100 AU from the sun (see map below).  No spacecraft has ever passed outside of the Heliosphere to date.


Image from Wikipedia showing a log scale plot of the solar system. For more info on parts of solar system, see Oort Cloud and Kuiper Belt

Tuesday, April 29, 2008

The History and Future of the Solar System

The Solar System was just sparse amounts of gas 5 billion years ago, Hydrogen and Helium were the main components (Approximately 2% were heavier elements left from another star).  The pre-solar-system nebula collapsed and began to spin.  Then, as more mass condensed at the center, gravity's effects began.  Then, over millions of years, density and energy heated the Sun's core.  Meanwhile, collisions between small, asteroid-like objects formed the first proto-planets.  Then, the Sun's core reached 18 million degrees, and Hydrogen fusion started.  The expulsion of energy and radiation cleared the inner solar system of debris, save the now fairly large proto-planets.  The extra gas ended up orbiting around the outer planets, forming the Gas Giants.  All remaining planetary objects were absorbed by the Gas Giants, turned into tiny moons, propelled back into the soon-to-be asteroid belt, or sent out into the Kuiper Belt or Oort Cloud.  Eventually all planets had "cleared their neighborhood", a term that means to eject all matter form their orbital paths with gravity.  No changes occurred for billions of years afterward, bringing us to the present.

 The Solar System is now 4.6 billion years old.  Every 1.1 billion years, the sun grows slightly larger, and increases by 10% in luminosity.  Within one billion years, the radiation from the Sun will become so powerful that all life on Earth will go extinct, and Mars will be the most habitable planet.  In 5 billion years, the Sun will swell to a red giant and swallow Mercury, Venus, and Earth.  Then, in an explosion the Sun will shed its outer layers into space and become a white dwarf (white dwarfs and other stellar explosions are explained here), and shortly after cool and become a black dwarf.  The frozen planets may orbit into eternity or the explosion of the Sun will send them into space.  Then, the gas from the Sun may help make new stars and planets, maybe for billions of years to come.

Saturday, April 26, 2008

Life in the Solar System

As billions of species come and go on our home planet Earth, we wonder, "Are we alone?"  Outside of our solar system, on extrasolar planets, life could be rare or bountiful.  But locally, here in our solar system, there are still candidates for life.  Recently, evidence of water, and possible evidence of bacteria, and other micro-organisms were revealed in trenches of ancient oceans on Mars, suggesting a habitable climate.  Two gigantic asteroids hit Mars right around the time that the fossils pinpointed the existence of water, leading some people to believe that these asteroids destroyed the magnetic field or some of the atmosphere of Mars.  Therefore, all life on the planet would go extinct, just like an extinction on Earth, but to a greater extent.  

Mercury has no atmosphere, Venus is too hot, the gas giants have no solid surface and objects farther out are too small or cold. So, the moons are the only possibilities left.  Europa, a Galilean moon of Jupiter has an icy surface floating above a freezing ocean, 2 to 100 km deep.  Tides from Jupiter and possible heat from Europa's core, keep this ocean from freezing.  Titan, the only moon in the Solar System with an atmosphere, also holds the ingredients to possible life, save the temperature.  Orbiting freezing Saturn, the only liquid on this moon is liquid nitrogen, collecting in pools on its surface.  Either of these moons could be subject to later spacecraft study, and as our knowledge of technology grows, it is only a matter of time, until we are no longer alone in the Universe...

Tuesday, April 22, 2008

The Oort Cloud and the Kuiper Belt

The Oort cloud is the spherical area of leftover debris from the beginning of the Solar System, including mainly asteroids, and some comets.  The Kuiper belt also contains this debris but it is a lot closer to the Sun, its inner limit being the orbit of Neptune.  In total, millions of asteroid-like bodies have been discovered in these areas, some of which being big enough to be moons, and one, called Eris, is classified as a dwarf planet and is larger than Pluto.  Eris, and a few other relatively large bodies also have moons in orbit around them (one body, discovered in 2003, has two moons!).  Also, comets orbiting elliptically around the sun usually pass through the Kuiper belt.  Periodical comets, ones that orbit continuously around the sun can travel out to the Oort cloud, and some escape the sun's gravity floating free into space.  New Horizons, a spacecraft that flew by Pluto in July 2015, also will explore some objects in the Kuiper belt objects from 2016-2020.  Many secrets of these zones are still waiting to be discovered.

Cosmic Microwave Background Radiation

Cosmic Microwave Background Radiation is the radiation by the Universe in its early stages (here, here and here), shortly after the Photon Epoch, about 400,000 years after the Big Bang or 13.7 billion years ago. Since it was formed close to the Big Bang, it can be used as a "timer" for the age of the Universe (because of light aging).  Today it counts for roughly .00005 of the density of the Universe.  It keeps the average temperature of space around 2.3 Kelvin.  If the CMBR (short for Cosmic Microwave Background Radiation) ever dies out the Universe will end in a Big Freeze.  Microwave instruments detect this Radiation, and it is being studied for a look at the early Universe.

Friday, April 18, 2008

Quasars

A quasar is a supermassive black hole (see here, here, here and here) at the center of a young galaxy.  The farthest are 28 billion light-years away, making them that most distant objects ever observed.  They are so far that the energy they emit to make them visible most be equivalent to over 100 galaxies or a trillion suns.  Over 100,000 quasars have been detected with more on the way.  Some quasars can even be viewed with a small telescope, due to their luminosity with equals around 2 trillion suns.  An average quasar absorbs 10 solar masses (10 times the sun's mass) each year.  The biggest consumption on record being 1000 solar masses per year or 600 Earths per hour!  No quasars are in our supercluster because once they absorb all the mass in their proximity, they die out and become ordinary black holes, leaving a regular galaxy behind.  Quasars are that most powerful objects in our known Universe.

Tuesday, April 15, 2008

Extrasolar Planets

In the past 200 years, people have asked, "Are there other solar systems?"  The answer came in 1992 when an extrasolar planet was discovered.  Due to the distance of these systems, only planets heavier than Earth have been discovered so far, the lightest being 2.6 times the Earth's mass and the most massive outweighing 8 Jupiters!  Extrasolar planets have been found orbiting around giant stars, white dwarfs, brown dwarfs and even pulsars (information on these objects here and here)!  A few systems have been confirmed two planets, and one system holds 6 candidates.  Naturally, most have been gas giants, but some have been seen very close to their parent stars, the closest being only under .05 AU from the star.  Hundreds of these mysterious bodies have been discovered, with hundreds more waiting to be confirmed.  To assist this search, Kelper (named after Johannes Kepler), a spacecraft launched in 2009, has a sole mission to detect these planets.  Who knows what mysteries lie on bodies beyond our solar system?

Sunday, April 13, 2008

Dark Energy

Dark Energy is a hypothetical type of energy believed to be the cause of Universal expansion.  It is believed to fill up about 70% of the Universe.  It exerts a negative pressure on its surroundings which is behind the Universe's expansion.  To explain the acceleration, "vacuum energy", an energy in empty space, was proposed.  As the Universe expands, more vacuum and dark energy are formed in the new space that is created.  This, in turn, adds to the negative pressure that the Universe is exerting.  The Dark Energy's density is nearly unchanged as the Universe expands but the density of Dark Matter decreases.  This steadily increases the domination of this energy. This chain reaction, unless stopped by a different factor will lead the Universe to a Big Freeze or a Heat Death, possibly preceding a Big Rip.  

Tuesday, April 8, 2008

Dark Matter

Dark Matter is a form of invisible matter found in our Universe. It is invisible because it does not interact with electromagnetism. It also does not interact with atoms because unlike most matter, dark matter does not have an interaction with the strong nuclear force. Virtually the only way this matter can be detected is through gravitational effects on ordinary matter or by blocking light through gravitational light bending. Dark matter is believed to be made of neutrinos, axions, and other odd particles. Dark matter makes up a major part of the Universe's mass, and contributed to the beginning of the Universe.

Friday, April 4, 2008

The Tachyon

One well-known exotic particle is the tachyon.  A tachyon is a hypothetical particle that travels faster than the speed of light.  This odd particle seems to defy detection, and many scientists think it might not exist.  If the tachyon did exist it would defy many logical paradoxes.  The tachyon would be able to travel backwards in time, an action that is impossible by the theory of relativity.  But the theory could stay intact if the tachyon couldn't transmit information.  So the tachyon alters the physics of the Universe by itself, proposing three possibilities.  One is the easy way out, just saying that tachyons do not exist.  The second is that, although particles can, information cannot travel faster than the speed of light.  Three, the horrifying choice, is the possibility that the general theory of relativity, even approximately at an larger-than-quantum scale, is false. Scientists have proposed this particle real mass, also defying many previously believed theories, such as the fact that anything with real mass travels at subliminal (below light) speeds. Quantum physics have yet to explain this mysterious particle.

Heat Death of the Universe

This fate of the Universe (note 5) begins 100 trillion years from now when stellar formation has come to a halt.  Over the next 10^30 years, planets, stars, and eventually galaxies will decay gravitationally and start to flow freely in space.  From 10^30 to 10^40 years, all protons will decay and all matter will be converted into photons and gamma rays.  All that remained after this era was black holes.  As the age of the Universe soars to a googol (10^100) years Black holes will evaporate due to Hawking Radiation and all the will remain are gamma rays and the occasional photon.  

Thursday, April 3, 2008

Antiparticles

For most particles, there is an antiparticle.  An antiparticle has the opposite charge and the same mass as its particle partner.  Since particles and antiparticles annihilate each other, it is well-known that there are many more particles than antiparticles.  Antiparticle played apart in the creation of matter in the early Universe.  They also are the cause of Black Hole Evaporation. Because of these unbalanced amounts, antiparticles are not found naturally.  They are engineered in a lab by destroying another particle.  Particles with a quark composition have an antiparticle that contains antiquarks.  Also, two antiprotons, two antineutrons, and two antielectrons (also called the positron) would produce an antihelium atom.  Antiparticles mirror most particles, and they are very similiar with most properties.

Friday, March 28, 2008

The Electron

The Electron is an elementary particle found in the atom.  It is a lepton, and is stable, although it is possible that an electron may decay in 10^26 years (average).  The electron is the basis for the study of orbitals and atomic bonding.  Electrons are so small that their exact location is never determined and, like other particles have a wave form.  The electron has a negative charge (note 4). 

Electromagnetism

Electromagnetism is a force that effects anything with an electrical charge.  Also, electrically charged objects produce an electromagnetic field.  Like gravity, an electromagnetic field weakens with distance.  Electromagnetism is the force we observe most often and explains most phenomena seen by humans (with the exception of gravity, of course).  Atomic bonding, molecular interaction, and even some particle interactions all are caused by the electromagnetic force.  This force is carried by the photon.

The Neutron

The Neutron is an elementary particle found in the nucleus of the atom with the proton.  Its neutral charge is caused by the quark composition (udd or up, down, down) because the charges of the quarks add (up=2/3 + down=-1/3 + down=-1/3 = 0) to zero.  Bound inside the nucleus neutrons are stable, but the free neutron (synthetic) is unstable, having a half-life of about 885 seconds (approx. 15 minutes).  It interacts with all four forces and through beta decay, it becomes a proton.  The neutron is the heaviest particle in the atom.

Wednesday, March 26, 2008

The Proton

The proton is an elementary particle found in the nucleus of an atom. Its quark composition is uud or up, up, down. The charges of these quarks add (up=+2/3 up=+2/3 and down=-1/3) to +1, which is why the proton is positively charged. After the discovery of the electron, a positively charged particle was theorized to balance the atom. It interacts with all four forces (gravity, electromagnetism, weak nuclear force, and the strong nuclear force) and it is the second-heaviest particle in the atom (just short of the neutron). The proton is the only member of the Hydrogen nucleus and the number of protons in an atom determines atomic number. Protons are very well-known particles.

Monday, March 24, 2008

Strong Nuclear Force

The Strong Nuclear Force (Strong Interaction) is the most powerful force in our Universe.  Up until recently, it was thought that this was the force holding atomic nuclei together against repelling protons.  But this was found only to be an effect of the real Strong Nuclear Force (once the real force was discovered this effect was named the Residual Strong Nuclear Force).  The real force holds hadrons, but primarily protons and neutrons (collectively called nucleons) together.  This force is carried by gluons (named for glue) which connect quarks.

Wednesday, March 19, 2008

Weak Nuclear Force

The Weak Nuclear Force (also called the Weak Interaction) is a process that causes beta decay. This process involves a neutron turning into a proton. To do this, a neutron must not only lose in mass, but one of its quarks has to change from a down to a up quark. To do this it must eject a W boson which separates into a electron and an electron antinutrino. This decay happens in the proton-proton chain discussed here. Leptons can also emit W bosons and become corresponding nutrinos. Also, quarks can absorb or emit a Z boson. W and Z bosons are the particles that carry the Weak Nuclear force.


Tuesday, March 18, 2008

Black Hole Evaporation

An important question about Black Holes. Do they die? Hawking proposed Black hole evaporation, a theory in which Black Holes lose mass due to the separation of particle-antiparticle pairs. Vacuum fluctuations cause one particle to escape while its partner falls in. The negative particle falls in so the end equation is the Black Hole losing one particle. A massive Black Hole absorbs more Cosmic Background Radiation than it loses in mass because of Hawking Radiation. Because of this, until the Universe expands further and the Cosmic Radiation fades, a massive Black Hole will live forever. Eventually though, all Black Holes will evaporate. At the end of its life, a Black hole explodes with a temperature of over one quadrillion (1,000,000,000,000,000) degrees Fahrenheit with the force of over one billion atomic bombs.

Monday, March 17, 2008

Heavier Fusion

After a star exhausts its Hydrogen fuel, it either stops shining, or if it is massive enough, continues on to heavier elements. A red giant star, beyond its Hydrogen rations begins to fuse Helium. Helium, through the triple alpha process (a process where two Helium atoms fuse to form Beryllium, and then another alpha particle joins, forming Carbon) can produce Carbon, which produces Neon, Oxygen, Silicon, Nickel, and as alpha particles (note 3) are added to these heavier elements, forming Nickel, and finally iron. If a star reaches an iron core it explodes in a supernova, explained here. Only massive stars can obtain iron cores, with temperatures in the center soaring to 90 trillion degrees.

Sunday, March 16, 2008

Burning Hydrogen

All stars, including our Sun, begin their lives burning Hydrogen. For stars the mass of our sun or less, the process of burning is the proton-proton chain. Two Hydrogen atoms fuse to form a deuterium atom. This is the longest step because it takes a while for a proton to release energy and become a neutron. Then another Hydrogen atom fuses in forming Helium 3, a light isotope. Then this atom fuses with another He3 atom and releases two protons to become Helium 4, the regular isotope. This process takes over 10^9 years to complete (over a billion years), and that's why the sun is still shining.

The most common production of Helium in stars heavier than our sun is done in a cycle called the Carbon-Nitrogen-Oxygen Cycle (CNO cycle for short). The most common CNO cycle begins with a Carbon 12 atom (this atom is given because today's stars have a small metallic content). Then a Hydrogen atom fuses in, creating Nitrogen 13. Then as a positron departs a C13 is left. Then another Hydrogen fuses in creating N14. Then another H creating Oxygen 15. Then another positron leaves forming N15 (note that in all the steps metioned so far about the CNO cycle energy is released). Then, as a last Hydrogen atom fuses in, a Helium 4 atom is ejected leaving a C12 atom to restart the process again. A star like our sun burns its Hydrogen in 10 billion years, while more massive stars only burn it for less than 10 million years.

Gravity and Its Effects

Gravity, one or the four fundamental forces of the Universe has a devastating effect on our world. It is the force that created the stars and galaxies, and the force that destroys them. Gravity causes moons to orbit planets, that orbit stars, the orbit galaxy centers, that orbit in clusters, which orbit in superclusters. Also, it holds other types of groups like star clusters together. Examples of its effects can be seen in the end of stars' lives. A star such as our sun will expand into a red giant and shed its outer layers into space. The core the star would be left to collapse under its own gravity until its atoms are packed so tightly that a match box of material from its would weigh as much as a full-grown elephant. This remnant is called a white dwarf.

For a star whose core is more massive than 1.4 the sun's weight, a supernova occurs. This happens when a giant star runs out of hydrogen fuel. The star fuses heavier and heavier elements until the core is iron. Stellar fusion is discussed here and here. When the star attempts to fuse iron, however energy is taken in rather than released, upsetting the balance between contracting gravity and out flowing energy. Matter bounces off the core as it contracts and powered by tiny neutrinos the star rips apart. After a supernova, there are two possibilities for the star's core. One is to become a neutron star (also called a pulsar). The core collapses and atoms break under the extreme pressure. Protons and electrons combine to form neutrons and the particles are packed as tight as possible, forming a neutron star. Over a solar mass of matter is packed into a sphere only about 15 miles across. A pinhead of material from this star would weigh more than the Titanic. For the first million years of its existence, the neutron star's magnetic field is so strong (thousands of times as strong as Earth) that intense radiation beams are shot from its poles. If the beam passes Earth, a pulse is recorded earning it the name pulsar.

The other possibility for a star's core after a supernova, one weighing more than four suns, is that it collapses further to become a black hole. A black hole is gravity's greatest victory. It sucks matter in, and since its escape velocity exceeds the speed of light, no radiation is emitted, making it "black". More on Black holes can be found here, here, here and here. Everything in our Universe (almost) is orbiting another body because of gravitational pull. The Moon is orbiting the Earth, which in turn is orbiting the Sun, which is orbiting the center of the galaxy, which is orbiting the Local Cluster, orbiting the Local Supercluster. For a spherical body, the strength of the gravitational field at any point is proportional to the body's mass and inversely proportional to the square of the distance of the object. Another star interaction caused by gravity is called a nova. This is when one star of a binary system turns into a black hole. It sucks in mass from its companion, disturbing the energy-gravity balance. The star becomes unstable and eventually explodes. In other words, gravity is the force that rules our Universe.

Wednesday, March 12, 2008

Cosmic Inflation

When the Universe was very young, many scientists believe it went through a period of exponential expansion (note that expansion is exponential because that space seems to actually "grow" between two objects, rather than them moving apart). Evidence for this theory includes characteristics of the Universe today. A rapid expansion would flatten the Universe, which is reflected in the current Universe's structure.  The Universe is also roughly homogeneous, which means that a period of quick expansion may have delayed interactions between particles.  Also, based on the current information, the geometry of the Universe is the same in all directions which means its also isotropic, also a sign of rapid inflation.  Scientists have yet to explain this theory, but they have suggested the existence of an inflaton, a particle or field used to explain inflation.  But the real cause of this expansion, or proof that it even happened is currently out of reach. 

Black Holes and Universe Budding?

Some people believe that the Universe itself is a giant Black hole, expanding and eventually contracting in a Big Crunch. Then a chain of universes follow from successive Big Crunches and Big Bangs. But if a Black hole can form a Universe, what about Black holes formed by collapsed giant stars? This opens an idea called Universal Budding. It states that a Black hole in our Universe can begin a baby universe. It would then expand into another dimension and set separate laws of physics. Thousands of universes could bud from ours.

Tuesday, March 11, 2008

The Big Bang

Before the quark epoch of the Universe (10^-12 to 10^-6 seconds after the Big Bang), theories were less accurate and more speculative.  This is due to the massive energy needed to duplicate the reactions.   Among these early epochs are the Planck epoch, the grand unification epoch, the inflationary epoch, and the electroweak epoch.  The first and most unknown period of the Universe was the Planck epoch (up to 10^-43 seconds after the Big Bang).  This epoch (named after Max Planck) happened before the first unit of Planck time was over.  Due to the fact that this is supposed to be the smallest unit of time possible, the happenings during that time would defy all laws of physics.  During the Planck epoch, all four of the forces were of equal strength, and therefore unified.  Scientists think that the development of the Quantum Gravity theory will shed light on the secrets of this epoch.  The second of the Universe's epochs was the grand unification epoch (10^-43 to 10^-36 seconds).  During this epoch gravity separated from the other three forces.   The inflationary epoch (10^-36 to 10^-32 seconds) was an epoch of extremely fast expansion.  The conditions of the Universe had not settled enough for quarks or anti-quarks to form.  This epoch is discussed more specifically in another article.

 The electroweak epoch (10^-36 to 10^-12 seconds) was the last of these early epochs.  This period was cool enough to separate the electromagnetic and the weak nuclear force (combined) from the strong nuclear force.  The beginning of this epoch allowed the formation of W, Z and Higgs bosons.  Also, the rapid, exponential expansion that occurred during the inflationary epoch had slowed to allow particles such as quarks and neutrinos, to form.  No matter what happened in the early Universe, the actual Big Bang and its causes may never be fully understood.  The best theory about the cause is the Big Bounce theory (discussed briefly in the Big Crunch article).  But this subject is mainly a topic of imagination.

Hadron and Lepton Epochs

Before these eras, the early Universe was dominated by quark-gluon plasma. Th first of the two, the Hadron epoch, began .000001 seconds after the Big Bang. In this epoch, quarks became stable enough to bind together and form hadrons such as protons and neutrons. At 1 second after the Big Bang most hadrons and anti-hadrons annihilated each other leaving a residue that would later form atomic nuclei in a process called Big Bang Nucleosynthesis. The lepton epoch lasted from 1 to 3 seconds after the Big Bang. In that time leptons, including electrons, and anti-leptons were formed. At the end of the epoch, these pairs were annihilated as well, leaving another small residue. After these epochs the Universe was dominated by photons until about 380,000 years after the Big Bang.

Monday, March 10, 2008

Big Bang Nucleosynthesis

This stage of the Universe lasted 17 minutes from 3 to 20 minutes after the Big Bang.  It occurred over the entire Universe.  The process started one second after the Big Bang when the temperature and density dropped enough to support stable protons and neutrons.  The temperature stayed high for nuclear fusion only enough time for atom nuclei (note 2) lighter than Beryllium to form.  After this period was over no more atoms fused until stellar formation  This material was the beginning of the formation of stars and galaxies millions of years later.


The Formation of Stars and Galaxies in the Universe

For a while after the Big Bang the Universe had almost no structure.  The Universe was a void filled with sparse amounts of Hydrogen, Helium (formed by early fusing of Hydrogen under high pressure), dark matter, and dark energy.  Then, as the Universe cooled, dark matter clumped together.  Gravity attracted gases and more dark matter to add to the clump.  A proto-galaxy had formed.  Within a proto-galaxy, pressurized gases formed the first stars.  It is believed that these stars had no metal content.  As the Universe continued to expand more galaxies formed, the very galaxies we look at today were created.  Developing proto-galaxies have been seen through telescopes about 13.2 billion light years away, making the age of the Universe there about 500 million years.

Sunday, March 9, 2008

Geometry of the Universe

There are three possibilities describing the Universe's geometry. If the constant curvature (how much the average curve of a shape is) of the Universe is zero, the Universe is flat. In simpler terms, you could go indefinitely in one direction, you would never return to where you were. If the curvature is more than zero, the surface of the universe is a finite sphere. If it is less than zero, the surface of the Universe is hyperbolic (or a place where more than one line can be drawn through a point that is parallel to a given line). These three theories of the shape of the Universe describe the three types of geometry: Euclidian, Spherical, and Hyperbolic.  Knowing the Universe's geometry is critical for finding out when, how, or if the Universe is going to end.   


The Big Rip

The Big Rip is yet another theory describing the possible fate of the Universe.  In this theory, the expansion of the Universe reaches infinite speed (due to to balance between Dark Energy and Dark Matter), and everything in it, even atoms, are ripped apart.  According to the theory, 60 million years before the end of the Universe, every galaxy but the Milky Way  would be out of visible range from the Earth.  Right before the end, the galaxy and the solar system (if the solar system still exists) would be gravitationally unbound.  A split second before the end, everything down to atoms would be ripped apart as the expansion speed of the Universe reaches infinity.  If this theory is correct, the Big Rip will happen in approximately 50 billion years.

The Big Crunch

If the amount of Dark Energy in the Universe was reduced to lower than the amount of Dark Matter a phenomena called the Big Crunch will occur.  The Universe would slow down its accelerated expansion and reverse.  Black holes would engulf stars and eventually entire galaxies as everything contracted.  As the shrinking increased in speed, black holes would swallow each other and the universe would end as an almost indefinitely tiny singularity, all matter squeezed into a small speck at the center of a black hole.  A variation of this theory is called the Big Bounce.  It includes the possibility that a Big Crunch would lead to another Big Bang, therefore creating a  second universe.  This theory opens up another important question.  Are we the first, five hundredth, or the one trillionth universe?  This question is explored in another article.

The Big Freeze

Of all the Ultimate fates of the Universe the Big Freeze is the most supported. This theory proposes that the Universe reaches a temperature too cold to sustain life. This would happen because as the Universe expands, the Cosmic Background Radiation (formed immediately after the Big Bang) would fade away completely causing the temperature of the Universe to drop. Once a star dies its gases used to create another star wouldn't group together and begin fusion because extreme cold means no moving particles. The Universe's temperature would reach absolute zero (-459.67 Fahrenheit) and stay that way forever.