2012: Fear No Supernova

Share:

Source: NASA

Post Date: 2011-12-29

Topics: Astronomy & Space, Astronomy,

Summary: Given the incredible amounts of energy in a supernova explosion -- as much as the sun creates during its entire lifetime -- another erroneous doomsday theory is that such an explosion could happen in 2012 and harm life on Earth. However, given the vastness of space and the long times between supernovae, astronomers can say with certainty that there is no threatening star close enough to hurt Earth.

 

Related Topics

» Astronomy

» Astrophysics

» Big Bang

» Black Holes

» Dark Matter

» Planets

» Mars

» Moon

» NASA

» Pluto

» Saturn

» Solar System

» Stars

» Sun

» Earth

» Jupiter

» Gravity


Supernova 1987A was the closest exploding star seen in modern times. It occurred in the Large Magellanic Cloud, a small galaxy that orbits our own Milky Way. Images taken by NASA's Hubble Space Telescope were combined to make this composite of the blast's expanding debris. (Credit: NASA / ESA / P. Challis and R. Kirshner (Harvard-Smithsonian Center for Astrophysics))
Given the incredible amounts of energy in a supernova explosion -- as much as the sun creates during its entire lifetime -- another erroneous doomsday theory is that such an explosion could happen in 2012 and harm life on Earth. However, given the vastness of space and the long times between supernovae, astronomers can say with certainty that there is no threatening star close enough to hurt Earth.

Astronomers estimate that, on average, about one or two supernovae explode each century in our galaxy. But for Earth's ozone layer to experience damage from a supernova, the blast must occur less than 50 light-years away. All of the nearby stars capable of going supernova are much farther than this.

Any planet with life on it near a star that goes supernova would indeed experience problems. X- and gamma-ray radiation from the supernova could damage the ozone layer, which protects us from harmful ultraviolet light in the sun's rays. The less ozone there is, the more UV light reaches the surface. At some wavelengths, just a 10 percent increase in ground-level UV can be lethal to some organisms, including phytoplankton near the ocean surface. Because these organisms form the basis of oxygen production on Earth and the marine food chain, any significant disruption to them could cascade into a planet-wide problem.

Another explosive event, called a gamma-ray burst (GRB), is often associated with supernovae. When a massive star collapses on itself -- or, less frequently, when two compact neutron stars collide -- the result is the birth of a black hole. As matter falls toward a nascent black hole, some of it becomes accelerated into a particle jet so powerful that it can drill its way completely through the star before the star's outermost layers even have begun to collapse. If one of the jets happens to be directed toward Earth, orbiting satellites detect a burst of highly energetic gamma rays somewhere in the sky. These bursts occur almost daily and are so powerful that they can be seen across billions of light-years.

A gamma-ray burst could affect Earth in much the same way as a supernova -- and at much greater distance -- but only if its jet is directly pointed our way. Astronomers estimate that a gamma-ray burst could affect Earth from up to 10,000 light-years away with each separated by about 15 million years, on average. So far, the closest burst on record, known as GRB 031203, was 1.3 billion light-years away.

As with impacts, our planet likely has already experienced such events over its long history, but there's no reason to expect a gamma-ray burst in our galaxy to occur in the near future, much less in December 2012.

Recommend this page on Facebook, Twitter and more...

Story Source

This article uses materials provided by NASA. For further information, please contact the source cited above.


Related Stories

'Supernova of a Generation' Shows Its Stuff: Astronomers Determine How Brightest and Closest Stellar Explosion in 25 Years Happened



Top Science News

One black hole or two? Dust clouds can explain puzzling features of active galactic nuclei
Researchers at the University of California, Santa Cruz (UCSC), believe clouds of dust, rather than twin black holes, can explain the features found in active galactic nuclei (AGNs).... full story »

Measuring each point of a beam of light
If you want to get the greatest benefit from a beam of light-whether to detect a distant planet or to remedy an aberration in the human eye-you need to be able to measure it.... full story »

Success of blood test for autism affirmed
One year after researchers published their work on a physiological test for autism, a follow-up study confirms its exceptional success in assessing whether a child is on the autism spectrum.... full story »

Possible Subsurface Lake near Martian South Pole
A new paper published in Science this week suggests that liquid water may be sitting under a layer of ice at Mars' south pole.... full story »

Wireless Pressure-Sensing Eye Implant Could Help Prevent Blindness
Researchers at Caltech have developed an implantable pressure sensor that can reside in the human eye while wirelessly sending data about the eye's health to the medical professionals.... full story »


Search Science News Digest:

Enter a keyword or phrase to search ScienceNewsDigest's archives

Free Subscriptions

View hourly updated newsfeeds in your RSS reader:

RSS Newsfeeds
Social Bookmarking

Recommend this page on Facebook, Twitter and more...