Submitted by Pluto_and_Charon t3_y8e3al in space
grammarGuy69 t1_iszs61n wrote
Do you think it's more likely to find direct evidence of life or indirect evidence? If it's the latter, what sort of markers would we be looking for as proof?
Pluto_and_Charon OP t1_it08v28 wrote
Scientists will be wary of announcing the discovery of alien life unless the evidence is direct and unequivocal. However, given how hostile Mars' present surface is, it's very unlikely we'll find living microbes on the surface. Instead, we're really looking for fossilised microbes inside rocks, because Mars was a much more habitable planet in the ancient past (4.5-3.5 billion years ago).
Definitive proof of alien life on Mars would therefore have to meet multiple of these expected criteria:
- Biogenic sedimentary structures like stromatolites. This is what everyone is hoping we find because these features are very large and obvious. We find them in Earth rocks of similar age.
- Chirality. Organic (carbon-based) molecules often have two 'mirror versions' of each other, a "left handed" version and a "right handed" version. Without the action of life, these molecules are usually in equal abundance, but biological processes tend to generate molecules that are very skewed towards one and not the other. IIRC, on Earth molecules overwhelmingly tend to be left-handed, and this is a big giveaway that Earth has life
- Microscopic things with cell-like morphology and cell-like sizes (micrometres)
- Evidence of various cell morphs, representing multiple species or life stages
- Evidence of cell clustering, indicating of cell division, or colonies of cells which organise into shapes like spirals or tubes
- Presence of biomolecules such as certain lipids which are only produced by biology
- Isotope fractionation. As a byproduct of biological processes that are universal to all Earth organisms, the abundance of certain isotopes such as those of Carbon is skewed in a way that is very distinctive of life
Pluto_and_Charon OP t1_it09ns2 wrote
Since neither rover has a microscope or state-of-the-art mass spectrometer (due to budget and mass constraint limitations), we're therefore going to have to wait until we can study Mars rocks in a lab on Earth to really answer these questions - unless Perseverance just stumbles across a stromatolite lol.
Fortunately, NASA's already set that plan in motion. The rocks that Perseverance is coring will be brought back to Earth by a series of robotic missions, they'll return to Earth in the early 2030s. They will be the most scientifically valuable materials in history! Only then will we be able to definitively answer - yes or no- whether the area Perseverance is exploring had alien life.
kldload t1_it0nzz8 wrote
Mark my words. SpaceX will land a human on Mars before NASA gets anywhere CLOSE to doing a sample return.
sonsofgondor t1_it1nudf wrote
How close do you realistically think SpaceX is to landing humans on Mars? They haven't even crashed on Mars yet. I bet we get the cores before humans get to Mars
kldload t1_it1ujg4 wrote
What vehicle will nasa use? Sls? Ha!
sonsofgondor t1_it1yw8c wrote
Whatever one they want to. Nasa have been there many times. SpaceX should aim to get people on the moon before mars
kldload t1_it2e289 wrote
Lol they will need a bigger launch vehicle and a sizable return vehicle. Masa has never landed a payload of that size. They have no vehicle brother
sonsofgondor t1_it4stll wrote
Whats the biggest payload SpaceX has landed on another planet? SpaceX hasn't even landed a gram on another rocky body
wgp3 t1_it2yxly wrote
You clearly don't understand what the mars sample return mission is. You don't need sls. I don't think they have a launch vehicle chosen yet but I believe falcon9/heavy would work as would Vulcan.
The sample return mission isn't some huge vehicle carrying humans to grab samples and come back. So they don't need a big rocket like that. Perseverance is gathering the samples and leaving them on the surface. A future mission will include a small rover and two helicopters I believe (like ingenuity) to collect the samples. These samples will be delivered to MAV (mars ascent vehicle) which is basically a beefed up sounding rocket. This will then drop the samples off in an orbiter that will then make its way back to earth.
The MAV and the rovers and the copters and the orbiter are all in development right now as well. We should see the next launch for this mission in the 2027 time frame, wherever that launch window is. And then I believe there will be another in 2030 or so. Then the samples come back by 2031 or something like that. Hard to remember off the top of my head.
While this is a complex mission it isn't too herculean of a task to keep within a few years of the plan considering sample caching is already started and ingenuity specs barely need to be modified.
While I honestly have no doubt that nasa will be using spacex for carry astronauts to mars one day, I don't think that day will be before 2032. SpaceX is already behind on starship. Not by a whole lot but they are behind their ambitious goals. We probably won't see a first test flight until the start of next year. They'll have to refine their earth operations and their lunar operations over the next few years. I doubt they even make the 2025 human landing on the moon at their current rate of progress (although faster than anyone else could do).
Starship could make the sample return moot though. It's much more plausible that by 2030 starship can do an unmanned mars round trip. The scale of samples that could be brought back would dwarf MAV. But we shall see.
kldload t1_it4gbr2 wrote
What the hell would they use to lift everything off the surface? They need several vehicles and haven’t even started development on any of it. Also funny that you mentioned two spacex vehicles hahaha. NASA is nothing but an astronomy club these days
wgp3 t1_it8y0q8 wrote
Are you illiterate? I literally wrote out exactly what they would use. MAV. Mars ascent vehicle. It's a beefed up sounding rocket. They literally have started on these "vehicles". I work with people who currently are doing trajectory analysis for MAV. Of course I mentioned two spacex vehicles. They would be great for sending the orbiter and even the lander/MAV. Maybe learn what you're talking about before just saying shit? Especially since NASA is currently operating more vehicles on Mars than anyone else and has extensive knowledge on landing and orbiting it.
As for the astronomy jab, I repeat they have more vehicles operating on Mars than anyone else. They have satellites around Jupiter. They're about to send a flying laboratory to Titan. They operate the international space station. They do a bit more than astronomy you dolt.
kldload t1_it93alx wrote
What’s with all the personal attacks haha check your ego mate
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