Life may have thrived on early Mars, until it drove climate change that caused its demise. Early in its history, the red planet likely would have been habitable to methanogens, microbes that make a living in extreme habitats on Earth, according to a study that simulated the conditions on a young Mars. The discussion of Mars being renewed with life has been brought to the forefront by people like Elon Musk and Jeff Bezos who see it as the next step in human colonization efforts. Musk, who is the CEO of SpaceX, said that a manned mission is to reach Mars this decade. He founded SpaceX in 2002 with the goal to reduce transportation costs and colonize Mars. Musk believes making life multi-planetary will ease life on an overcrowded earth. However, roughly 3.6 billion years ago, the climate of Mars shifted from being habitable to inhabitable when liquid water disappeared from the surface. Although the cause of this transition remains unknown, new findings suggest that the loss of an important greenhouse gas transformed Mars into a dry planet.
Aside from the necessities to sustain life like water and atmosphere, there are other challenges that people would face if they were to live on Mars. For example, the temperature gets very, very cold at night, below -100 degrees Fahrenheit. Mars also has dust storms, high levels of radiation, and less gravity than Earth. Because of that melanin in skin and protective domes against radiation would be a necessity for human life to thrive. Melanin microspheres are the most effective at absorbing X-rays, UV light, and other types of radiation. Cosmic radiation is a hazard to humans in space or on Mars. A black melanin coating on spacecraft and spacesuits would be a futuristic lifesaver. Melanin is found in most organisms across the plant and animal kingdoms, as well as in bacteria and fungi. Though best known for pigmentation, melanin also provides valuable protection from radiation.
Eumelanin—the pigment that produces hair, skin, and eye color—also holds great potential to shield humans and equipment from radiation in space. A composite of fungal melanin and polymers, was delivered to the International Space Station in Earth's low orbit in 2019, where it was tested for its ability to protect against space radiation. The results of those tests has inspired new ideas about how to protect humans from harmful radiation on Earth and in outer space.
Melanin, a dark brown or black pigment natural to people whose ancestry is from tropic regions or sub Saharan Africa, is found across all biological kingdoms and has been shown to absorb harmful ionizing radiation frequencies that can damage cells. Contrary to popular belief climate change could quickly change the color of the Earths populations as many who are without Melanin would simply die off if conditions become too harsh. if there is a selective survival reason or cultural benefit to a skin color. As long as you have genome variation in the underlying population genetic skin color mix, you can get shifts in a matter of a few centuries. This has happened at least four times in Europe. (1) Light skinned Neanderthal mixing with modern human from sub Saharan Africa creating darker Cro-Magnon, (2) dark hunter-gatherers to olive skinned Asiatic in the early Neolithic, (3) olive to pale in the Late Neolithic/early Bronze Age Mediterranean. Also (4) in Nordic areas from dark to pale over about 1ky in the Mesolithic.
Where the fitness benefit is especially high, color change on existing variation can happen in two to three generations. Color change in moths due to pollution from coal took place in two to three moth generations and was one of the first observed cases of natural selection directly documented. About 3.8 billion years ago, Mars was a reasonably pleasant place. It had a thick atmosphere filled with carbon dioxide that kept it warm. Rivers trickled into lakes across its surface. Some researchers think there might even have been an ocean. If we stopped or limited Mars' atmospheric loss, we could hypothetically pursue a number of warming methods. Over the next hundreds of years, we could restore as much as 1/7th the amount of liquid water as Mars once had in its oceans, and bring back some aspects of that period of habitability.
Nobody knows if there was life on Mars 3 billion years ago, but it's now a hostile place. The water's mostly gone. So is a lot of that cozy atmosphere. To try and find out what went wrong, NASA scientists have sent a spacecraft called the Mars Atmosphere and Volatile Evolution Mission, or MAVEN. With each swing around Mars, MAVEN actually dips into the planet's atmosphere, gathering data. The results are published today in two journals — Geophysical Research Letters and Science — and they reveal something remarkable: Mars' atmosphere is actually leaking into space. It's leaving at a rate about 100 grams per second. That doesn't seem like much, but you add it up over a couple of billion years and it's enough to remove the entire atmosphere.
The cause is our friendly neighborhood star, the sun. It's constantly shooting out high energy particles known collectively as the solar wind. [The wind] streams outward at a gas flow at about a million miles per hour. On Earth, our magnetic field blocks the solar wind. Particles become tangled in it before they can ever reach our precious air supply. There is no magnetic field on Mars, so when the solar wind reaches the Red Planet, the atmosphere gets stripped away.