Claim:
Dangerous cosmic rays will pass by Earth tonight, causing harm to those who leave nearby personal devices turned on.
Judgement:
As the total solar eclipse of April 8, 2024 approached, Snopes’ inbox began to fill with the familiar claim that “tonight” cosmic rays would pass close to Earth, endangering those who leave powered-on personal electronic devices nearby . . The text of these “copypasta” messages was virtually identical in all cases:
Tonight from 12:30 PM to 3:30 AM, don’t forget to turn off your mobile phone, tablet, computer, etc. and place them far from your body. Singapore TV announced this news. Please tell your family and friends. Tonight, from 12:30 PM to 3:30 AM, our planet will have very high radiation. Cosmic rays will pass very close to the Earth. Therefore, switch off your mobile phone. Do not leave the device close to your body as this can cause terrible damage. If you don’t believe it, you can check it on Google and NASA BBC News. Send this message to all the people who are important to you. Everyone is in danger, take care of yourself.
This viral message, which we last checked in 2017, is a hoax that has been circulating online since 2014. Since then, the message has been repeatedly debunked, by media outlets such as Agence France-Presse in 2021, which noticed the message being widely shared. in Thailand. In 2019, Vishvas News also addressed this claim as it spread in India.
Where do cosmic rays come from?
Cosmic rays have two sources. One type of cosmic rays comes from supernovas, which are massive stars that “die,” collapsing under their own gravity and then turning into black holes or neutron stars. As they go through this process, the supernovas hurl charged particles – protons and electrons – through space. These particles move so fast that they can easily penetrate through matter. The second source of cosmic rays is the sun. Solar flares and other solar events can also emit charged particles that reach Earth.
The good news is that Earth’s magnetic field protects us from these cosmic rays, according to the International Atomic Energy Agency (IAEA):
The Earth is shielded by a magnetic field that bounces the charged particles from pole to pole, creating two giant donut-shaped belts populated by energetic electrons and protons. The magnetosphere deflects cosmic rays and protects us from solar flares. Sometimes cosmic rays reach us, but without causing any damage, just like other low levels of radiation we are regularly exposed to.
This video from the television program Nova explains it well:
How exposed are we?
According to the IAEA, the average person is exposed to 3.5 millisieverts of radiation per year, of which only 10% is due to cosmic rays. A much larger share of such radiation comes from medical tests such as X-rays, mammograms or CT scans, the agency says. There are other natural sources, including radon, that are emitted from the soil in certain areas.
Our level of exposure to cosmic rays varies because the higher we are in space, the more we are exposed. For example, we are more exposed to cosmic rays during high-altitude flights that pass over the poles. This is of particular concern to flight crews on long-haul flights, a risk about which the Federal Aviation Administration (FAA) has issued a warning to airline employees.
People who travel into space are even more at risk of harmful radiation. NASA also warns its employees about the risk of cancer that may be caused by that radiation, including:
Radiation exposure during space exploration is one of the biggest threats to astronauts’ health. Associated risks include carcinogenesis, degenerative tissue effects, central nervous system effects and acute radiation syndromes. The radiation environment outside Earth’s protective atmosphere consists of energetic protons and heavy nuclei that pose a danger to living organisms. The damage caused by energetic nuclei has been shown to cause marked biological damage compared to radiation on Earth, leading to large uncertainties in the projection of health risks and clouding the effectiveness of potential radiation countermeasures.
But as long as we remain on Earth, and thanks to our planet’s magnetic field, cosmic rays normally do not pose a significant threat to human health, according to the US Centers for Disease Control.
Sources:
Cosmic rays: why we shouldn’t worry. April 12, 2021, https://www.iaea.org/newscenter/news/cosmic-radiation-why-we-should-not-be-worried.
‘FACT CHECK: Post asking people to turn off their phones because of cosmic rays is fake’. Vishvas NewsJune 26, 2019, https://www.vishvasnews.com/english/society/fact-check-post-asking-people-to-switch-off-phone-due-to-cosmic-rays-is-fake/.
information@eso.org. ‘Missing Link found: supernovae cause black holes or neutron stars’. Www.Eso.Org, https://www.eso.org/public/news/eso2401/. Accessed April 8, 2024.
Kasprak, Alex. ‘FACT CHECK: Will dangerous cosmic rays pass close to Earth ‘tonight’?’ SnackingMay 24, 2017, https://www.snopes.com//fact-check/dangerous-cosmic-gamma-rays/.
‘Old hoax circulating on Thai social media, warning people to turn off mobile phones due to harmful cosmic rays passing through Earth.’ Fact checkingMarch 12, 2021, https://factcheck.afp.com/old-hoax-circulates-thai-social-media-warning-people-turn-mobile-phones-due-harmful-cosmic-rays.
Space Radiation – NASA. March 16, 2023, https://www.nasa.gov/directorates/esdmd/hhp/space-radiation/.
US EPA, OAR. Health risk of radon. August 14, 2014, https://www.epa.gov/radon/health-risk-radon.
What airline crews need to know about their occupational exposure to ionizing radiation. Federal Aviation Agency, October 2003, https://apps.dtic.mil/sti/tr/pdf/ADA423589.pdf.
What is solar activity? -NASA. https://www.nasa.gov/image-article/what-solar-activity/. Accessed April 8, 2024.