Mars Rover Perseverance Discussion Thread

[Dfthu]

Here is the empty sample capsule 

And here is the Coring bit with the sample tube

Perseverance Mars rover's first rock sample goes missing (yahoo.com)

[tater]

 

 

[StrandedonEarth]

Explore with Perseveance!

https://mars.nasa.gov/mars2020/surface-experience/?drive=0&site=7

[JoeSchmuckatelli]

https://www.cbsnews.com/news/photos-nasa-perseverance-rover-ancient-flash-floods-mars/

Flash flooding 

[JoeSchmuckatelli]

https://www.space.com/mars-rover-perseverance-confirms-lake-delta-jezero-crater

 

[John Casey]

On 7/30/2020 at 3:24 PM, Nightside said:

How does the ‘copter control itself with just two blades?

To catch enough lift with so few molecules to push against, the helicopter's two pairs of blades will have to spin in opposite directions at a speed roughly eight times faster than a passenger helicopter on Earth

[JoeSchmuckatelli]

1 hour ago, John Casey said:

To catch enough lift with so few molecules to push against, the helicopter's two pairs of blades will have to spin in opposite directions at a speed roughly eight times faster than a passenger helicopter on Earth

The purpose of the counter rotating blades is to effectively zero out the torque.

The motor spinning one blade alone would actually result the body of the drone spinning counter to the blade (to the observer each part - the blade and the body would spin in opposite directions) and thus be uncontrollable.  By having two blades spinning in opposite directions, they allow the body of the drone to be stable. 

Lift is determined by the pitch of the blades - each blade can be rotated on its axis to control how much it bites into the air, and then direction is determined by tilting the rotor in the direction of desired travel 

Edited October 11, 2021 by JoeSchmuckatelli

[JoeSchmuckatelli]

https://science.howstuffworks.com/transport/flight/modern/helicopter6.htm

 

[tater]

 

 

[tater]

 

 

[JoeSchmuckatelli]

Lava rocks, not sedimentary. 

https://www.cnn.com/2021/12/15/world/perseverance-rover-mars-findings-scn/index.html

Reading this, I'm moving away from 'Mars was once a life sustaining planet' towards 'it never really had a chance'. 

There is a line in there to the effect that the surface Percy drives across is not the bottom of the original crater. Yet the rocks they are finding are igneous rather than the sedimentary they were hoping to find.  There are indicators that the igneous rock has interacted with water in the past - and some adjacent features look like sedimentary deposits... But it is not like the bottom of a long term lake. 

[kerbiloid]

Lava and water... Hmm...

They should be cautious and try gypsum.

Spoiler

 

[JoeSchmuckatelli]

Speaking of Mars and the search for wa-wa...

https://www.cnn.com/2021/12/16/world/exomars-water-mars-grand-canyon-scn/index.html

(Canals indeed) 

[Scotius]

That's an interesting find. Large amounts of subsurface water near the equator - warmest place on the planet. And one with probably the densest atmosphere available, due to great depth of the canyon. Could there be microbial life shallow enough, to be in reach of a rover's drill?

[JoeSchmuckatelli]

1 hour ago, Scotius said:

That's an interesting find. Large amounts of subsurface water near the equator - warmest place on the planet. And one with probably the densest atmosphere available, due to great depth of the canyon. Could there be microbial life shallow enough, to be in reach of a rover's drill?

Subsurface microbes the most likely.  We have tons of extremophiles - even in rock

[sevenperforce]

3 hours ago, JoeSchmuckatelli said:

Subsurface microbes the most likely.  We have tons of extremophiles - even in rock

But those extremophiles didn't evolve independently of the rest of Earth's ecosystem.

The question is whether Mars ever hosted life that was complex and diverse enough to produce the selection pressure required to create extremophiles.

Speaking of extremophiles in rock, I'm reminded with amusement of the moment in one of the ID cases (I think it was Kitzmiller) where Michael Behe gave "expert" testimony about the probability of a particular evolutionary pathway in bacteria happening even once in a billion  years being something along the lines of 1:10¹⁷.

The cross-examining attorney said, "You are aware, aren't you, that there are approximately 4 billion bacteria in a single teaspoon of soil, are you not?"

Behe answered, "Yes."

The attorney said, "And there are about a million teaspoons in a cubic meter of soil, isn't that correct?"

Behe nodded.

The attorney said, "Okay, so if my math is correct, you would need about 20 cubic meters of soil to have approximately 10¹⁷ bacteria, isn't that right?"

Behe said, "Yes, that sounds right."

The attorney then asked, "And it is generally accepted that there are more than 20 cubic meters of soil on the planet, isn't that correct?"

Edited December 17, 2021 by sevenperforce
I really should not confuse Bebe with Behe at this point.

[NFUN]

34 minutes ago, sevenperforce said:

But those extremophiles didn't evolve independently of the rest of Earth's ecosystem.

The question is whether Mars ever hosted life that was complex and diverse enough to produce the selection pressure required to create extremophiles.

Speaking of extremophiles in rock, I'm reminded with amusement of the moment in one of the ID cases (I think it was Kitzmiller) where Michael Behe gave "expert" testimony about the probability of a particular evolutionary pathway in bacteria happening even once in a billion  years being something along the lines of 1:10¹⁷.

The cross-examining attorney said, "You are aware, aren't you, that there are approximately 4 billion bacteria in a single teaspoon of soil, are you not?"

Behe answered, "Yes."

The attorney said, "And there are about a million teaspoons in a cubic meter of soil, isn't that correct?"

Behe nodded.

The attorney said, "Okay, so if my math is correct, you would need about 20 cubic meters of soil to have approximately 10¹⁷ bacteria, isn't that right?"

Behe said, "Yes, that sounds right."

The attorney then asked, "And it is generally accepted that there are more than 20 cubic meters of soil on the planet, isn't that correct?"

it sounds like the attorney here was being deliberately obtuse tbqh

[sevenperforce]

4 minutes ago, NFUN said:

it sounds like the attorney here was being deliberately obtuse tbqh

No, it's not that at all -- it's how you discredit an expert witness, as an attorney.

Expert witnesses are annoying because they are able to give opinion testimony based on evidence that wouldn't otherwise be admissible. So if you can discredit an expert by showing that they don't know what they are talking about, you can make the jury (or the judge, in this case) disregard their opinions.

In this situation, Behe created his "one chance in 10¹⁷" opinion based on completely nonsensical parameters. The attorney cannot just stand there and say "You're wrong and here's why" because attorneys are not allowed to testify; they are only allowed to ask questions. So, as an attorney, you have to lead the witness by the nose, one question at a time, until he discredits himself.

[wumpus]

1 hour ago, sevenperforce said:

But those extremophiles didn't evolve independently of the rest of Earth's ecosystem.

The question is whether Mars ever hosted life that was complex and diverse enough to produce the selection pressure required to create extremophiles.

Speaking of extremophiles in rock, I'm reminded with amusement of the moment in one of the ID cases (I think it was Kitzmiller) where Michael Behe gave "expert" testimony about the probability of a particular evolutionary pathway in bacteria happening even once in a billion  years being something along the lines of 1:10¹⁷.

The cross-examining attorney said, "You are aware, aren't you, that there are approximately 4 billion bacteria in a single teaspoon of soil, are you not?"

Behe answered, "Yes."

The attorney said, "And there are about a million teaspoons in a cubic meter of soil, isn't that correct?"

Behe nodded.

The attorney said, "Okay, so if my math is correct, you would need about 20 cubic meters of soil to have approximately 10¹⁷ bacteria, isn't that right?"

Behe said, "Yes, that sounds right."

The attorney then asked, "And it is generally accepted that there are more than 20 cubic meters of soil on the planet, isn't that correct?"

When the witness testified to the existence of soil before the existence of life, he easily discredited himself as an "expert".  The attorney should have used seawater.

[NFUN]

2 hours ago, sevenperforce said:

No, it's not that at all -- it's how you discredit an expert witness, as an attorney.

Expert witnesses are annoying because they are able to give opinion testimony based on evidence that wouldn't otherwise be admissible. So if you can discredit an expert by showing that they don't know what they are talking about, you can make the jury (or the judge, in this case) disregard their opinions.

In this situation, Behe created his "one chance in 10¹⁷" opinion based on completely nonsensical parameters. The attorney cannot just stand there and say "You're wrong and here's why" because attorneys are not allowed to testify; they are only allowed to ask questions. So, as an attorney, you have to lead the witness by the nose, one question at a time, until he discredits himself.

given how it was phrased, he could just as easily meant that the odds of such a mutation having occurred to be those odds, not the odds of a single bacterium to have such a mutation in... some time frame in the attorney's mind. The "expert" was ambiguous, but the attorney made a few assumptions instead of asking for clarification. 

 

of course, you may have been paraphrasing, but the wording you have was what I was referring to

 

edit: actually, given how the "expert" gave a timeframe, my alternate interpretation is more reasonable than the attorney's assumption

Edited December 18, 2021 by NFUN

[JoeSchmuckatelli]

3 hours ago, sevenperforce said:

those extremophiles didn't evolve independently of the rest of Earth's ecosystem

There is some thought vis panspermia that early Earth's ecosystem was populated by only  extremophiles.      That their adventures and waste created the environment that we currently enjoy. 

 

If there is merit to this - there could be extremophiles that could never evolve out of the state due to the inhospitable rest of Mars... And possibly that whatever extremophiles got a foothold went extinct for lack of a world wide ecosystem (islands of life trapped in shrinking isolated pools) 

 

[kerbiloid]

5 hours ago, JoeSchmuckatelli said:

panspermia

The weak place of the panspermia is: do you know another planet more comfortable than the Earth as a cradle of life?

[SunlitZelkova]

3 hours ago, kerbiloid said:

The weak place of the panspermia is: do you know another planet more comfortable than the Earth as a cradle of life?

Venus *might* have had surface water long enough for simple life to evolve (3 Ga, using the conservative estimate of 3.465 Ga (out of 4.54), thus 1,075,000,000 years, for Earth as the time for life to evolve).

That's not to say panspermia is likely though (or even life), just that there may have been a place.

Unlike Mars though, uncertainty surrounding Venus is purely due to lack of study of the planet's past, as opposed to un-encouraging finds.

Edited December 18, 2021 by SunlitZelkova

[kerbiloid]

2 hours ago, SunlitZelkova said:

Venus *might* have had surface water long enough for simple life to evolve (3 Ga, using the conservative estimate of 3.465 Ga (out of 4.54), thus 1,075,000,000 years, for Earth as the time for life to evolve).

The Vebusian surface doesn't have continental platforms, but is covered with tiles ("tesseras").

This tells that it didn't have a fast core separation and lightweight minerals surfacing, like the Earth did, probably due to the proto-Moon capture/impact event and partial melting.

This tells that probably, though Venus has lost all its water, it didn't have a period of time where a planet-wide ocean was existing, but it had boiling shallow lakes losing the water as steam, which then was splitted by UV and leaving the atmosphere (as H) and oxidizing the rocks (as O).

[JoeSchmuckatelli]

8 hours ago, kerbiloid said:

The weak place of the panspermia is: do you know another planet more comfortable than the Earth as a cradle of life?

The weak part of panspermia is that it remains purely speculative.  Should we find microbes on Mars, Europa and elsewhere it might be argued to be factual. Then we need to find extra solar DNA bearing life and maybe it becomes the standard model