NASA has said it wants to put an American on Mars in the 2030s, according to an article on Space.com. The mission would be humanity’s furthest space endeavor yet. What environment exists there? Has it always been so dead?
The popular website that delivered the announcement cited a quote from NASA Administrator Jim Bridenstine, who in turn made the statement after President Donald Trump suggested it at a press conference celebrating the 50th anniversary of the Apollo 11 Moon landing. In his statement, Bridenstine specifically refused to rule out putting boots on Mars in the year 2033. While Mars is commonly known as “the Red Planet,” its environment and atmosphere hold many mysteries—and it may not have always been so barren.
Life on Mars
Our “blue planet” and the barren wastelands of Mars have some surprising ecological similarities. Dr. Laird Close, Professor of Astronomy and Astrophysics at The University of Arizona, pointed to Mars’s evidence of volcanoes and past volcanic activity as well as its plate tectonics as examples. “It certainly has wind erosion,” he said. “It has had water erosion in the past. As well, it has icy poles, kind of like the Earth does.” Dr. Close said that these factors suggest that Mars may once have had life—not necessarily “Little Green Men,” but life nonetheless.
On the other hand, any visiting astronauts would have to take some serious precautions. “The average temperature on Mars is just 220 Kelvin—that’s -53 degrees Celsius or -63 degrees Fahrenheit,” Dr. Close said. “However, it’s worth mentioning, too, that when it gets very, very warm, it can sometimes get above 0 degrees Celsius at the equator, say, in summer.”
Dr. Close also said that Mars’s atmosphere is poisonous—it’s composed mainly of carbon dioxide, which of course humans can’t breathe. Furthermore, the atmosphere on Mars is just 6 millibars compared to Earth’s 1,000 millibars (or 1 bar). That means Mars’s atmosphere is just 0.5 percent that of Earth’s, which is an extremely thin atmosphere.
Expanding on Mars’s atmosphere, it’s actually so thin that it causes problems for any surface-dwelling life form that requires water. “It is a very low-pressure atmosphere,” Dr. Close said. “Because it has only got about half of a percent of a normal atmosphere, you cannot have enough atmospheric pressure to hold the water molecules together in a liquid form. They may more naturally just want to turn into water vapor.” He pointed out that even if someone were able to bring a solid block of ice to the surface, as it reached above freezing temperatures it may just turn directly into a vapor instead of changing forms to liquid. This type of atmosphere eliminates the possibility of advanced animals living on Mars’s surface.
What about at its poles? Mars’s polar ice caps are visible when using very powerful telescopes. What happens at the point where the poles end and the planet’s warmer regions begin? “Water ice at the poles never melts, but the solid carbon dioxide does actually sublimate into gaseous carbon dioxide,” Dr. Close said. “Solid carbon dioxide is known to many as dry ice.” He also pointed out that there is evidence of abundant water on Mars, but unfortunately, it’s deep within the planet. The temperature is lower just beneath the surface than it is at the surface, so more ice is present. One would have to dig deep into the planet before finding any ice warm enough to make water.
If NASA Administrator Jim Bridenstine’s outlined plans occur as expected, astronauts could set foot on Mars in less than 15 years. When they get there, they can expect to find a cold climate with minimal atmosphere—an atmosphere with such low pressure it can’t hold liquid water. Only time will tell what else they may discover when they set foot on the red planet.
Dr. Laird Close contributed to this article. Dr. Close is Professor of Astronomy and Astrophysics at The University of Arizona. He earned his Ph.D. in Adaptive Optics from the renowned University of Arizona Astronomy Department, where he now teaches.