Research will gauge hypothetical disaster: A supernova close to Earth

May 02, 2014 by Brendan M. Lynch

Seen from our planet, the flash could be brighter than a multitude of suns—and might be followed by a ruined ozone layer, an upsurge in radiation, and a wave of cancers and mutations in humans and other creatures that would crest for hundreds or even thousands of years.

It's not the premise of Hollywood's latest apocalypse flick. These disasters could follow if a supernova ignited close to Earth—say, within 30 of our planet.

This month, NASA awarded $500,000 to a research team based in part at the University of Kansas to make the most painstaking assessment ever of the potential damage from a near-Earth supernova.

"A supernova is the explosion of a star, which comes at the end of the 'life' of large stars, when they collapse after running out of fuel," said Adrian Melott, professor of physics and astronomy, who leads the KU Astrophysics Biology Working Group that earned the grant. "But, there can be other types, sometimes set off by the merger of two stars."

Melott is working with Andrew Overholt of MidAmerica Nazarene University and Brian Thomas of Washburn University—both KU alumni—to perform computer modeling and data analysis on supercomputers such as the National Science Foundation's Teragrid.

In part, the team's predictions will hinge on evidence of previous supernovae.

"This 2.5 million-year event is the only one we have concrete evidence of, and it's nearly enough to affect the Earth and give us a dose of radiation and possibly climate change without being a mass killer," Melott said. "There has been iron-60 found in mud cores taken from the ocean bottom, about 2 to 2.5 million years old. Iron-60 is a radioactive isotope that basically can only have been dumped there by a supernova possibly 150 light years away. The nearest in recorded history was about 7,000 light years away."

If humans lived to tell the tale, the consequence of a nearby supernova would change life for eons.

"We'd begin to get radiation effects," said Melott. "Depletion of the and resulting danger from ultraviolet light is common to this as well as many other astrophysical radiation events. There would be an increase of cosmic rays for hundreds or thousands of years, some of which would increase radiation on the ground—such as muons or neutrons. This might increase the cancer and mutation rates. Some have argued that it may change the cloud formation rate or the rate of lightning, leading to climate change."

But how likely is such an occurrence? While a supernova isn't expected to explode in our galactic neighborhood anytime soon, the KU researcher said that supernovae occur in the Milky Way on a surprisingly regular basis.

"There are 2 or 3 per century in our galaxy," he said. "On average, you'd get one within 200 light years every million years or so, and less often for closer ones. The killer events within 30 light years are likely every few hundred million years. Most of them would be easily spotted—but there is a type from merger events that could happen with no warning, as they are due to the merger of dead stars that we don't see."

In the three-year study, the researchers will rely on other data on supernovae from NASA space missions such as Swift, Chandra, GALEX and Fermi to estimate photon and cosmic ray intensity, solar and terrestrial magnetic field effects and atmospheric ionization. The KU team will greatly improve on past estimates and produce the first detailed models linking all of these effects together.

Melott said that in a worst-case scenario, a close supernova could bring on a large-scale die-off of life on Earth.

"It can happen," he said. "It probably has. However, there is as yet no concrete evidence that a specific extinction is connected to a ."

Explore further: Will the sun explode?

add to favorites email to friend print save as pdf

Related Stories

Fear no supernova

Dec 16, 2011

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 ...

Hubble monitors supernova in nearby galaxy M82

Feb 26, 2014

This is a Hubble Space Telescope composite image of a supernova explosion designated SN 2014J in the galaxy M82. At a distance of approximately 11.5 million light-years from Earth it is the closest supernova ...

Supernova cleans up its surroundings

Apr 10, 2014

(Phys.org) —Supernovas are the spectacular ends to the lives of many massive stars. These explosions, which occur on average twice a century in the Milky Way, can produce enormous amounts of energy and ...

Recommended for you

Big black holes can block new stars

16 hours ago

Massive black holes spewing out radio-frequency-emitting particles at near-light speed can block formation of new stars in aging galaxies, a study has found.

POLARBEAR seeks cosmic answers in microwave polarization

16 hours ago

An international team of physicists has measured a subtle characteristic in the polarization of the cosmic microwave background radiation that will allow them to map the large-scale structure of the universe, ...

New radio telescope ready to probe

19 hours ago

Whirring back and forth on a turning turret, the white, 40-foot dish evokes the aura of movies such as "Golden Eye" or "Contact," but the University of Arizona team of scientists and engineers that commissioned ...

Exomoons Could Be Abundant Sources Of Habitability

Oct 20, 2014

With about 4,000 planet candidates from the Kepler Space Telescope data to analyze so far, astronomers are busy trying to figure out questions about habitability. What size planet could host life? How far ...

Partial solar eclipse over the U.S. on Thursday, Oct. 23

Oct 17, 2014

People in most of the continental United States will be in the shadow of the Moon on Thursday afternoon, Oct. 23, as a partial solar eclipse sweeps across the Earth. For people looking through sun-safe filters, from Los Angeles, ...

User comments : 0