Mars is performing a wonderful, colorful conjunction, and it’s easy to spot. At 9:30 or 9:45, tonight or the next clear evening, look low in the direction of sunset. Unless you have hills, houses, or something else blocking the low northwestern sky, you’ll see dazzling Venus down there. It’s the night sky’s brightest object, so you can’t miss it. Then look to its upper left. Now you’ll see two little stars, 300 times less bright than Venus. One is orange, the other blue-white. Binoculars would dramatically bring out these pastel colors, and is worth dragging them out to have a look.
Needless to say, the little orange “star” is the planet Mars. The blue one is Regulus, the brightest star of Leo the Lion. Each evening at that same time for the next week, Mars and Regulus will hang out very close together, getting spectacularly close on a few nights. It’s well worth the effort to see them.
On the other hand, since Mars has now reached its dimmest point of the year and is currently teeny-tiny through telescopes, few are now observing the Red Planet. But many are still thinking about it.
That’s because the Red Planet remains the most anticipated place for humans to land. It’s been our goal since forever. But as planning for manned visits to Mars continues, and results accumulate from astronauts who’ve spent a long time on the ISS, astrobiologists grow more concerned about space travel’s medical consequences.
They’ve found that in weightless conditions, bone and muscle vanishes at 1% per month, and some of the loss is irreversible. Hearts shrink in size, and cardiac capacity goes steadily downhill. Space is just not good for you.
Things really get bad when you leave Earth orbit and pass outside our magnetosphere, which guards us from solar and cosmic radiation. Apollo astronauts all saw flashes of light resembling shooting stars cross their visual fields about once a minute as ions ripped through their eyeballs and brains. Their radiation exposures were not trivial and, years later, Alan Shepard speculated whether his time in space had perhaps given him the leukemia that ultimately took his life in 1998.
More astronauts could well have perished. An intense solar mass ejection occurred just four months after the Apollo 16 astronauts returned to Earth in 1972. Had they still been off-planet, the 400 rem radiation dose could have easily killed them.
Recent studies of radiation hormesis surprisingly suggest that very low exposures may be harmless or even beneficial for health, and if verified could change the assessment about the long-term risk of hanging out on the Red Planet. Nonetheless, brain neurons would get destroyed by Martian surface radiation. One biologist estimates that during a two-year Mars mission an astronaut might lose between 13% and 40% of his brain cells, which greatly exceeds the 5% annual neuron necrosis suffered by some Alzheimer’s patients.
So if you decide it’s more prudent to simply observe it from here, especially during this week with its wonderful conjunction, count me in for company. Otherwise, it’ll be a bit of a wait, since Mars will soon vanish behind the sun’s glare, and the next close Martian visit and worthwhile apparition won’t begin until December of next year.
Join the family! 
