radiation

It is unclear what isotope of uranium the men are alleged to have sought - though all can emit harmful radiation - and their intended purpose for it.

"We can at least treat 50 patients per day for chemotherapy and radiation and even more than that. Other hospitals can do a lot of surgeries," the doctor tells me.

This enhanced ability to regenerate could help the body heal damage caused by radiation, which is a common side effect of cancer treatments.

Some participants also received radiation therapy as recommended by their doctors.

If Mars once had an ozone layer shielding its surface from ultraviolet radiation, that protective barrier could have made it far more hospitable to life billions of years ago.