Space travel changes the shape of Astronaut’s heart
From feelings of weightlessness to literally out-of-this-world views, the life of an astronaut is something to be envied—most of the time. Unfortunately, space is also really bad for the human body. According to a NASA study, it's bad for the human heart, too: time in space makes astronauts' hearts more spherical.
Gym buffs know you lose muscle mass when you don't work out regularly. Same goes for a heart in microgravity. "The heart doesn't work as hard in space, which can cause a loss of muscle mass," said James Thomas, M.D., ultrasound lead at NASA, in an American College of Cardiology news release.
For the study, 12 astronauts learned how to do ultrasounds so they could image their hearts before, during and after space travel. The NASA researchers found that their hearts became 9.4 percent more spherical, which could be a sign the muscle is not working as efficiently. Luckily, their hearts returned to their normal shapes once they were back on Earth, but the effects a longer spaceflight could have are anyone's guess.
There's a silver lining in all of this. The study not only tested what microgravity does to hearts in space—it also tested sophisticated mathematical models that the researchers had developed to predict what the hearts might do. The final results matched what their models had predicted, which means that they might be able to use them to predict what other, more earthly elements might do to the heart.
"It gives us confidence that we can move ahead and start using these models for more clinically important applications on Earth, such as to predict what happens to the heart under different stresses," said Thomas, also of Northwestern Medicine, in the 2014 release. That means the astronauts' heart images could eventually help scientists learn more about cardiac conditions that affect people on this planet
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Atronauts can actually see COSMIC RAYS in the space
The first person to report seeing cosmic rays was none other than Buzz Aldrin. During the Apollo 11 mission in 1969, he mentioned seeing strange flashes of light that took on a variety of shapes and dimensions. When astronauts say they're seeing things, people take them seriously, so by the time Apollo 16 and 17 took off there was a special detector on board to figure out what was going on. The results? The flashes were caused by high-energy charged particles, the stuff of cosmic rays. Over many more missions, the research continued, showing that the particles affected every astronaut differently: some could see them in bright conditions while others could only see them in the dark; some were so bothered by them that they had trouble sleeping while others couldn't see them at all.
Here's the problem: cosmic rays aren't just sci-fi jargon. They're really harmful. Specifically, they're radioactive fragments of atoms—mostly protons, but also some neutrons and electrons—that move at incredibly high speeds and tear through any molecules unlucky enough to be in their path. They're the reason radiation is a primary concern on future missions to Mars. The fact that astronauts are seeing them means that cosmic rays are hurtling into astronauts' eyes. Not good.
We know the flashes are cosmic rays, but we don't actually know the reason astronauts are seeing them. The rays aren't light, after all—they're just radioactive particles. Researchers have formed three theories about why astronauts can see them: one was that they were entering the eye and hitting the optic nerve. Another was that they were entering the astronauts' skulls and hitting the vision center of the brain.
The third theory is definitely scariest: the particles are traveling through the vitreous humor of the astronauts' eyes and emitting light in the form of something called Cherenkov radiation. As io9 puts it, "The light is coming from inside their eyeballs."