My husband and I have been watching Cosmos, it’s a thirteen part television series that originally aired on PBS in 1980 before either of us were born. I’ll sum up the content because there is too much: space, our planet, and various applicable theories. The series is hosted by Carl Sagan, a prolific astronomer and cosmologist. He also helped produce and write the series.

The eighth episode is called “Journeys in Space and Time” and Sagan discusses time travel, light speed, faster-than-light travel, and the fantastical future of spacecraft that could one day take humans to the extremely distant places in our universe and the implications of these activities.

One of the totally depressing results of sending humans barreling through space at nearly the speed of light is that when they return to Earth the people they left behind will be dead. That’s if there is even an Earth with life to return to because it will have probably been destroyed by the sun.

That scenario is a far-off one but NASA is eyeing a deep-space manned mission to an asteroid in 2021 and to Mars in 2035. Those missions will not have the macabre aspect of a near-light speed mission but they are not without risks.

For over 27 years NASA has been funding research that studies the impact space travel and living in space has on an astronaut’s health. A new study says the cosmic radiation that astronauts are exposed to on longer deep space missions can have detrimental affects on the brain.

The paper explains what happened when researchers at the NASA Space Radiation Laboratory at Brookhaven National Laboratory on Long Island exposed mice to iron particles they created in a particle accelerator.

The mice had impaired cognitive and biological abilities which means they couldn’t remember if they had left the garage door open when they left the house and they all misplaced their reading glasses.

Iron particles were chosen because they “pack a bigger wallop” than other particles and they are more difficult to engineer a shield or barrier against. “One would have to essentially wrap a spacecraft in a six-foot block of lead or concrete," said M. Kerry O'Banion, M.D., Ph.D., a professor in the University of Rochester Medical Center Department of Neurobiology and Anatomy and the senior author of the study

Now that NASA and researchers have identified the problem they can work on finding a solution before 2021.