General Question

Yellowdog's avatar

If the planet Mars was able to sustain an Earth-like atmosphere, what kinds of temperatures and life could it support?

Asked by Yellowdog (5126points) 3 weeks ago

Colder, I’m sure—but let’s say it if it had (or once had) oceans and atmosphere (probably inferior to Earth’s but could sustain life)—what would the temperatures be, and what kind of plants, vegetation, and creatures could exist in, or adapt to that gravity level?

I know that life is more likely to be found in several of the moons of Jupiter and Saturn.

Any discussion is acceptable but try to keep answers consistent with Mars’ gravity, distance from the sun, and temperatures. We can also add the possibility of an ocean regardless as to whether the planet ever actually had one.

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8 Answers

zenvelo's avatar

If Mars had an atmosphere as dense as Earth’s, the temperature would not be as extreme, as an atmosphere can retain heat.

While plants might thrive from less gravity, the growing season would have to be longer because of the distance from the Sun. That was one of the “scientific criticisms” of The Martian , but that can be overcome with mirrors and grow lights.

stanleybmanly's avatar

The problem is that Mars for a variety of reasons cannot hold onto an earth like atmosphere, and any life evolving there must reflect that fact. The missing atmosphere eliminates the possibility of surface water in a liquid form. Two of the reasons for Mars’ lost atmosphere also mitigate heavily against complex life forms enduring on Mars. The planet’s smaller mass renders escape velocities for atmospheric molecules much lower than here; but of even greater consequence to the atmosphere is the fact that Mars lacks the powerful magnetic field which protects us from having our gasses stripped away by the ionized particles propelled at hyper velocities by the solar winds. Any life evolving on or near the surface of the planet must evolve some method of coping with those particles, and the danger to multicelled organisms increases exponentially with growing complexity. The outlook for any life form large enough to be seen with the naked eye seems pretty grim to me.

LuckyGuy's avatar

Tardigrades could live there.

“Tardigrades are able to survive in extreme environments that would kill almost any other animal. Extremes at which tardigrades can survive include those of:

Temperature – tardigrades can survive:
A few minutes at 151 °C (304 °F)[51]
30 years at −20 °C (−4 °F)[52]
A few days at −200 °C (−328 °F; 73 K)[51]
A few minutes at −272 °C (−458 °F; 1 K)[53]
Pressure – they can withstand the extremely low pressure of a vacuum and also very high pressures, more than 1,200 times atmospheric pressure. Tardigrades can survive the vacuum of open space and solar radiation combined for at least 10 days.[54] Some species can also withstand pressure of 6,000 atmospheres, which is nearly six times the pressure of water in the deepest ocean trench, the Mariana trench.[22]
Dehydration – the longest that living tardigrades have been shown to survive in a dry state is nearly 10 years,[39][40] although there is one report of leg movement, not generally considered “survival”,[55] in a 120-year-old specimen from dried moss.[56] When exposed to extremely low temperatures, their body composition goes from 85% water to only 3%. As water expands upon freezing, dehydration ensures the tardigrades do not get ripped apart by the freezing ice.[57]
Radiation – tardigrades can withstand 1,000 times more radiation than other animals,[58] median lethal doses of 5,000 Gy (of gamma rays) and 6,200 Gy (of heavy ions) in hydrated animals (5 to 10 Gy could be fatal to a human).[59] The only explanation found in earlier experiments for this ability was that their lowered water state provides fewer reactants for ionizing radiation.[59] However, subsequent research found that tardigrades, when hydrated, still remain highly resistant to shortwave UV radiation in comparison to other animals, and that one factor for this is their ability to efficiently repair damage to their DNA resulting from that exposure.[60]

Irradiation of tardigrade eggs collected directly from a natural substrate (moss) showed a clear dose-related response, with a steep decline in hatchability at doses up to 4 kGy, above which no eggs hatched.[61] The eggs were more tolerant to radiation late in development. No eggs irradiated at the early developmental stage hatched, and only one egg at middle stage hatched, while eggs irradiated in the late stage hatched at a rate indistinguishable from controls.[61]

Environmental toxins – tardigrades are reported to undergo chemobiosis, a cryptobiotic response to high levels of environmental toxins. However, as of 2001, these laboratory results have yet to be verified.[55][56]
Outer space – tardigrades are the first known animal to survive in space. In September 2007, dehydrated tardigrades were taken into low Earth orbit on the FOTON-M3 mission carrying the BIOPAN astrobiology payload. For 10 days, groups of tardigrades were exposed to the hard vacuum of outer space, or vacuum and solar UV radiation.[3][62][63] After being rehydrated back on Earth, over 68% of the subjects protected from high-energy UV radiation revived within 30 minutes following rehydration, but subsequent mortality was high; many of these produced viable embryos.[54][64] In contrast, hydrated samples exposed to the combined effect of vacuum and full solar UV radiation had significantly reduced survival, with only three subjects of Milnesium tardigradum surviving.[54] In May 2011, Italian scientists sent tardigrades on board the International Space Station along with extremophiles on STS-134, the final flight of Space Shuttle Endeavour.[65][66][67] Their conclusion was that microgravity and cosmic radiation “did not significantly affect survival of tardigrades in flight, confirming that tardigrades represent a useful animal for space research.”[68] In November 2011, they were among the organisms to be sent by the U.S.-based Planetary Society on the Russian Fobos-Grunt mission’s Living Interplanetary Flight Experiment to Phobos; however, the launch failed. Tardigrades are one of the few groups to have survived Earth’s five mass extinctions.[69]

RedDeerGuy1's avatar

If you can take some the green house gasses from the atmosphere from Venus and relocate it to Mars then you could make both planets habitable to earth flora and fauna.

Yellowdog's avatar

Venus is actually my favorite. If those clouds were Earthlike, we’d have a cold planet rather than one hotter than flames. The sunlight never reaching the surface deflected back into space.
If Venus’ atmosphere was earthlike it would still be pretty hot, maybe 140 degrees F on average whereas the Earth is about half that. Polar regions might be ideal.

But Mars is starting to gain my ardor. Lets dispense with the God of War image and see it as Appalachian Iron red with an Arctic climate, an extra hour in the day, and lesser gravity making it easy to get around.

ARE_you_kidding_me's avatar

Mars has no magnetosphere, good luck living there

Yellowdog's avatar

Yes, if Mars AND Venus had magnetic fields, they’d be more viable.

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