Early on the morning of April 29, 2013, Commander Chris Hadfield’s residence got hit by a rock. Sounds like a story for a slow day on local news, except that Hatfield lives 225 miles above Earth in the International Space Station (ISS), and the offending rock was not thrown by vandals—it was merely passing by.

The rock in question is most likely just one of a huge number of similar pebbles that occupy our part of the Solar System. If you were to hold such an object in your hand, it would hardly seem threatening, but with gravity to accelerate it and without a thick layer of atmosphere to slow it down, these tiny objects can endanger spacefarers such as Hadfield.

Reaching speeds of 25,000 miles per hour, these rocks zip along between 12 and 20 times faster than a speeding bullet (depending on the bullet)!

Luckily, the object did not hit the main body of the space station, but it did punch a small hole in part of the ISS’s acre of photovoltaic solar panels. And while the station does sport various types of impact-resistant shielding, it could still be vulnerable to a larger object.

There have never been any lives lost due to an impact in space, but the Near Earth Object hunters at the B612 Foundation posted an ominous (and succinct) reminder to Facebook minutes after the event: “Definitely NOT good.”

It is estimated that hundreds of tons of similar objects fall to Earth every day, but with an ever-increasing presence beyond Earth’s protective atmosphere, current and future space explorers must be acutely alert to these potentially harmful rocks. We live in a densely populated part of the universe and have to remain vigilant.

Josh Roberts is a program presenter and astronomer at the California Academy of Sciences. He also contributes content to Morrison Planetarium productions.

Enter Caenorhabditis elegans, or C. elegans, scientists’ favorite worm. C. elegans has traveled on many spaceflights, making it the perfect study for aging and space travel.

Lifespan and aging rates in animals are influenced by numerous environmental factors, such as temperature, oxygen, and food intake. The effect of microgravitational space environments on aging remains poorly understood, in part because scientists must disentangle it from many other influences.

To address the question of spacefaring worms’ longevity, Yoko Honda of the Tokyo Metropolitan Institute of Gerontology examined ISS-flown C. elegans and compared them to earth-bound worms.

During the International C. elegans Experimental First project, scientists incubated worms and flew them for two days to the ISS. The worms resided on-board for nine days, and then returned to Earth to be flash frozen in liquid nitrogen. Control animals underwent the same procedures at the same time on the ground.

First off, the team noted that spaceflight suppressed the formation of particular compounds that normally accumulate with increasing age.

Secondly, the team looked at how spaceflight affected specific genes’ expression (not whether the genes smiled or frowned, but how efficiently the genes transfered the information they encode into actual proteins). The space travel downregulated seven of the worms’ genes: these genes encode proteins linked to neuronal or endocrine signaling. Honda and his colleagues observed that the inactivation of each of these genes led to an extension of the worms’ lifespan on the ground. So when the scientists “turned off” the genes that slowed down in space, the worms lived longer.

Space travel leads to longevity? Well, perhaps in worms. Further research is required, but the present study suggests that space-flown worms age more slowly compared with the control group, and hints that spaceflight may extend worm lifespan. Can astronauts hope for similar results? Far too early to tell…

The research appears in the current edition of Scientific Reports.

Image: Bob Goldstein, UNC Chapel Hill, Wikipedia