Earth’s Shields Protect Life on ‘One Strange Rock’

According to Space.com, planet Earth and the life it contains wouldn’t exist if it weren’t for the sun. But the sun also poses a serious threat to life, by constantly spewing harmful radiation into the solar system. Exactly how life on Earth managed to survive and thrive in the face of this danger is the subject of a new episode of “One Strange Rock,” which airs tonight (April 9) on the National Geographic Channel.

The new series explores all the strange coincidences that allowed life to arise and flourish on Earth. Each episode is narrated by astronauts, invoking the unique perspectives of those who have seen our planet from outer space. The first two episodes focused on how Earth “breathes” and how a violent history of cosmic collisions made our lucky planet the habitable world it is today.

Episode 3, titled “Shield,” will explore Earth’s natural defenses against the sun’s cosmic rays. Retired NASA astronaut Jeff Hoffman — who flew on five shuttle missions and helped to repair the Hubble Space Telescope in orbit — takes the lead. [The Sun’s Wrath: Worst Solar Storms in History]

While Earthlings couldn’t do without the sun, the vast amount of energy the star expels could also completely obliterate life in the solar system. Thanks to a combination of Earth’s atmosphere and a magnetic shell known as the magnetosphere, we don’t have to worry much about subatomic particles or UV radiation bombarding us. With a little sunscreen, we have all the protection we need down on Earth. In space, without our home planet’s natural defenses, the sun is far more hazardous.

Take Mars, for example. Because that planet has a thin atmosphere and no magnetic fields, what looks like it could have been a cradle for lifeis, in fact, a barren, uninhabitable landscape, likewise, scientists believe that Venus could have supported life billions of years ago.

Scott Kelly’s ‘Space Genes’

According to Futurism, Scott and Mark Kelly are identical twin brothers. They’re also both former astronauts. Scott spent a year living in the International Space Station, while Mark was here on Earth. The Twin Study, as it was called, was an effort to help scientists understand the effects of extended time in space. NASA already has a pretty good grasp of what happens to the body after six months on the ISS. But the effects after a year are far more important if we’re going to eventually send people to Mars, and beyond.

Though Scott Kelly returned to Earth in March 2016, scientists are still running the data to figure out the effects on his body and mind. At the 2018 Investigator’s Workshop for NASA’s Human Research Program in January, NASA released its findings, revealing that Scott returned safely, but something about his gene expression had changed, the liquor store near me.

NASA measured Scott’s metabolites, cytokines, and proteins before, during, and after his mission. Researchers learned that spaceflight is associated with oxygen deprivation stress, increased inflammation, and dramatic nutrient shifts that affect gene expression.

Furthermore, Scott’s telomeres (the ends of chromosomes that shorten as people get older) become longer while in space but shortened again within 48 hours of Scott returning to Earth.

Perhaps the most interesting discovery is the change to Scott’s genes. 93 percent remained unchanged after the year-long stay in space, but the remaining 7 percent — referred to as “space genes” — were expressed differently (the DNA itself wasn’t fundamentally altered, as some headlines stated and The Verge notes). These changes might have long-lasting effects on the immune system, DNA repair, bone formation networks, hypoxia (oxygen deficiency in tissue), and hypercapnia (an abundance of carbon dioxide in the bloodstream). 7 percent might sound insignificant, but in fact, it amounts to several hundred of genes.