Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Research investigates whether solar events could trigger birth defects on Earth

21.07.2015

Studies find airplane crews at high altitude are exposed to potentially harmful levels of radiation from cosmic rays.

"Neutrons which don't reach the ground do reach airline altitude," said Adrian Melott, professor of physics and astronomy at the University of Kansas. "Flight crews get a lot more radiation dose from neutrons. In fact, during solar particle events, airplanes are diverted away from the North Pole, where a lot more cosmic rays come down."


This image shows air showers ensuing from very-high-energy cosmic rays which can enter Earth's atmosphere from multiple directions.

Credit: Simon Swordy/NASA

But could these cosmic rays pose hazards even at sea level? In recent years, research has suggested congenital birth defects down on Earth's surface could be caused by these "solar particle events" -- spikes in cosmic rays from the sun that touch off the northern lights and sometimes hamper communications or the electric power grid.

Now, a new NASA-funded investigation has found radiation from solar events is too weak to cause worry at ground level. Results have just been published in the Journal of Geophysical Research and hailed as one of three "Editor's Choice" publications for the first quarter of 2015 by Space Weather.

"We looked at two different studies," said co-author Melott. "Both of them indicated a connection between cosmic rays and the rate of birth defects. One also associated mutations in cells growing in a petri dish with a 1989 solar particle event."

But Melott and colleagues Andrew C. Overholt of MidAmerica Nazarene University and Dimitra Atri of the Blue Marble Space Institute of Science have calculated the dose of radiation from a solar particle event to be less than a visit to the doctor might necessitate.

"We have a contradiction," Melott said. "Our estimates suggest that the radiation on the ground from these solar events is very small. And yet the experimental evidence suggests that something is going on that causes birth defects. We don't understand this, which is good. Something one doesn't understand is a pointer to an interesting scientific problem."

Melott and his co-authors looked at how cosmic rays from the sun create hazardous "secondaries" by reacting with the Earth's atmosphere.

"Cosmic rays are mostly protons," he said. "Basically, they are the nuclei of atoms -- with all the electrons stripped off. Some come from the sun. Others come from all kinds of violent events all over the universe. Most of the ones that hit the Earth's atmosphere don't reach the ground, but they set off 'air showers' in which other particles are created, and some of them reach the ground."

The air showers pose the most serious threat for the health of humans and other biology on the Earth's surface via "ionizing radiation," according to the researcher.

"Ionizing radiation is any radiation that can tear apart an atom or a molecule. It can affect life in many ways, causing skin cancer, birth defects and other things. Normally, about one-sixth of the penetrating radiation we get down near sea level is from secondaries from cosmic rays."

The authors looked carefully at two forms of radiation formed by solar particle events -- muons and neutrons -- finding that muons are the most dangerous to biology at the Earth's surface.

"Muons are a kind of heavy cousin of the electron," Melott said. "They're produced in great abundance by cosmic rays and are responsible for most of the radiation we get on the ground from cosmic rays. Neutrons can do a lot of damage. However, very few of them ever reach the ground. We checked this because some of them do reach the ground. We found that they're likely responsible for a lot less damage than muons, even during a solar particle event."

Of particular interest to the authors was a massive dose of solar radiation around the years 773-776 A.D.

"Carbon-14 evidence was found in tree rings in 2012 that suggests a big radiation dose came down around 775, suggesting a huge solar particle event, at least 10 times larger than any in modern times," Melott said. "Our calculations suggest that even this was mostly harmless, but maybe there is something wrong with our assumptions. We used ordinary understandings of how muons may cause damage, but perhaps there is some new physics here which makes the muons more dangerous."

The researcher said the next step in the investigation should be honing an understanding of how much exposure to muons DNA can withstand.

"In calculating the effect of muons, we used standard assumptions about what the effect of muons should be," Melott said. "Their physics is pretty simple, just that of an electron with a lot of mass. But no one has ever actually done much experimentation to measure the effect of muons on DNA, because under normal conditions they are not a dominant player. They are not important, for example, in nuclear reactor accidents. We would like to put some synthetic DNA in a muon beam and actually measure the effect."

###

The research was funded by the NASA program Astrobiology: Exobiology and Evolutionary Biology.

Media Contact

Brendan M Lynch
brendan@ku.edu
785-864-8855

 @KUNews

http://www.news.ku.edu 

Brendan M Lynch | EurekAlert!

Further reports about: DNA Earth Space birth defects cosmic rays damage defects neutrons radiation dose responsible sea level

More articles from Studies and Analyses:

nachricht New study: How does Europe become a leading player for software and IT services?
03.04.2017 | Fraunhofer-Institut für System- und Innovationsforschung (ISI)

nachricht Reusable carbon nanotubes could be the water filter of the future, says RIT study
30.03.2017 | Rochester Institute of Technology

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

Im Focus: Quantum-physical Model System

Computer-assisted methods aid Heidelberg physicists in reproducing experiment with ultracold atoms

Two researchers at Heidelberg University have developed a model system that enables a better understanding of the processes in a quantum-physical experiment...

Im Focus: Glacier bacteria’s contribution to carbon cycling

Glaciers might seem rather inhospitable environments. However, they are home to a diverse and vibrant microbial community. It’s becoming increasingly clear that they play a bigger role in the carbon cycle than previously thought.

A new study, now published in the journal Nature Geoscience, shows how microbial communities in melting glaciers contribute to the Earth’s carbon cycle, a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

New quantum liquid crystals may play role in future of computers

21.04.2017 | Physics and Astronomy

A promising target for kidney fibrosis

21.04.2017 | Health and Medicine

Light rays from a supernova bent by the curvature of space-time around a galaxy

21.04.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>