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-   -   What does Jupiter look like from Mars? (https://boards.straightdope.com/sdmb/showthread.php?t=815620)

Mr. Kobayashi 01-06-2017 08:14 PM

What does Jupiter look like from Mars?
 
Basically as the title - what does Jupiter look like in the Martian sky, especially at its closest point? Would it be visible with the naked eye (assuming you can, you know, breath)? I've JFGI but it turns out one image I've found is a big load of shite which is a shame.

Lemur866 01-06-2017 08:18 PM

Jupiter is easily visible from Earth, so of course it would be visible from Mars.

Mr. Kobayashi 01-06-2017 08:25 PM

Oh yeah, oops, I meant is it visible in any more...detail with the naked eye?

blue infinity 01-06-2017 08:38 PM

Earth orbits at 1 AU, Mars at around 1.5 AU and Jupiter at 5 AU.

So the distance between Earth and Jupiter varies between 4 to 6 AU, and the distance between Mars and Jupiter between 3.5 and 6.5 AU.

Jupiter would look pretty much the same from Mars, as it does from Earth.

Ignotus 01-06-2017 08:41 PM

You'd have a lot less of atmosphere bothering you on Mars though.

Stranger On A Train 01-06-2017 09:04 PM

Quote:

Originally Posted by blue infinity (Post 19902295)
Jupiter would look pretty much the same from Mars, as it does from Earth.

It would be somewhat brighter (at closest approach), and would also be clearer in a telescope because of the minimal atmosphere if Mars. The biggest difference would probably be in the increased visibility of the Galilaen moons, although they are still going to be barely more than dots in a portable telescope.

Stranger

Francis Vaughan 01-06-2017 09:42 PM

The Galilean moons might be an interesting question. They are just on the edge of visibility from the Earth. There is a lovely story from some decades ago of an amateur astronomer showing his little daughter a view of Jupiter with his telescope. She exclaimed - "But Daddy, they are the wrong way up!" After some confusion, it became apparent that she could actually see the moons with no optical assistance. It isn't that the moons are too dim - but that the angular separation from Jupiter is too little to avoid Jupiter's brightness making it too hard to separate. Very acute sight with very good atmospheric seeing could reasonably account for the little girl's capability. With no meaningful atmosphere on Mars the seeing will be very stable and clear. This might be enough to make seeing the moons a reasonable thing.

Jupiter's disk however will remain unresolved. It will still be a point.

Chronos 01-06-2017 11:36 PM

And being closer (at closest approach, at least) would also increase the angular separation.

watchwolf49 01-07-2017 12:03 AM

Bonus question: What would Earth look like from Mars?

Richard Pearse 01-07-2017 12:14 AM

Quote:

Originally Posted by watchwolf49 (Post 19902613)
Bonus question: What would Earth look like from Mars?

Presumably much the same as Mars looks like from Earth no? But with a faint blue tinge instead of red.

AK84 01-07-2017 12:18 AM

Quote:

Originally Posted by watchwolf49 (Post 19902613)
Bonus question: What would Earth look like from Mars?

Like so.

markn+ 01-07-2017 12:40 AM

The angular diameter of Mars as seen from Earth varies quite a bit depending on the position of the planets in their orbits, from about 3.5 arc seconds to over 25. So Earth's angular diameter as seen from Mars should vary in the same way, except Earth would be about twice the diameter, varying between 7 and 50 arc seconds.

coremelt 01-07-2017 02:53 AM

BTW, if you want to work out "what would X look like from Y" not just for the solar system but a bunch of real star systems take a look a Universe Sandbox:

http://universesandbox.com/

Not 100 percent accurate but it aims to use real world physics as much as they can with the limitations of desktop computers. For things like views of planets from any moon / planet in the solar system it should be pretty close.

dtilque 01-07-2017 02:57 AM

Quote:

Originally Posted by markn+ (Post 19902647)
The angular diameter of Mars as seen from Earth varies quite a bit depending on the position of the planets in their orbits, from about 3.5 arc seconds to over 25. So Earth's angular diameter as seen from Mars should vary in the same way, except Earth would be about twice the diameter, varying between 7 and 50 arc seconds.

Earth's albedo (fraction of light reflected back to space) is about twice Mars', so it's going to be brighter for that was well. I'd say that Earth as seen from Mars will be more like Venus from Earth, than Mars from Earth. Especially so since it'll go through phases like Venus does.

Quote:

Originally Posted by Francis Vaughan (Post 19902420)
Jupiter's disk however will remain unresolved. It will still be a point.

Jupiter is not quite a point to the naked eye. Stars are point sources and because of that, they twinkle due to atmospheric irregularities. Planets don't twinkle as much as stars do, because they do show just a bit of disk. This effect should be more pronounced when seeing Jupiter at Mars, but you still won't be able to see any detail on Jupiter.

Darren Garrison 01-07-2017 09:58 AM

Not what you are asking for, but a new photo of Earth and the moon from Mars.

Chronos 01-07-2017 10:01 AM

Earth from Mars will be brighter than Mars from Earth, for three reasons: First, Earth is closer to the Sun, and so gets more sunlight to reflect. Second, Earth has a much higher albedo, mostly due to clouds. Third, Earth is bigger. The net effect wouldn't be quite as bright as Venus is from Earth, but it'd still be plenty impressive. Especially since Earth would always be accompanied by another decently-bright point of light, Luna.

watchwolf49 01-07-2017 10:12 AM

Quote:

Originally Posted by Chronos (Post 19902996)
Earth from Mars will be brighter than Mars from Earth, for three reasons: First, Earth is closer to the Sun, and so gets more sunlight to reflect. Second, Earth has a much higher albedo, mostly due to clouds. Third, Earth is bigger. The net effect wouldn't be quite as bright as Venus is from Earth, but it'd still be plenty impressive. Especially since Earth would always be accompanied by another decently-bright point of light, Luna.

[wipes tear off cheek] ... sounds purdy ...

Darren Garrison 01-07-2017 10:25 AM

Quote:

Originally Posted by Chronos (Post 19902996)
Earth from Mars will be brighter than Mars from Earth, for three reasons: First, Earth is closer to the Sun, and so gets more sunlight to reflect. Second, Earth has a much higher albedo, mostly due to clouds. Third, Earth is bigger. The net effect wouldn't be quite as bright as Venus is from Earth, but it'd still be plenty impressive. Especially since Earth would always be accompanied by another decently-bright point of light, Luna.

Is this taking into account the fact that, being further than the sun from us, we always see a "full Mars", but Earth, being closer to the sun than Mars, is only a "full Earth" when it is on the opposite side of the sun from Mars, and only in partial phase (or entirely dark) when closer to Mars?

Chronos 01-07-2017 10:54 AM

Ah, right, forgot about phases. While which effect would dominate would depend on the phase, I think the net effect would still be that Earth is usually brighter. But I haven't run the numbers.

watchwolf49 01-07-2017 11:19 AM

Venus is currently an evening star ... look to the west as soon as it's fairly dark after sunset ... Venus will be the brightest star far and away ... roughly half illuminated ... someone with even a small telescope can verify this ... I haven't ...

harmonicamoon 01-07-2017 02:17 PM

What would Jupiter look like from Europa?

I am thinking about moving to Europa.

Weisshund 01-07-2017 02:45 PM

Quote:

Originally Posted by harmonicamoon (Post 19903510)
What would Jupiter look like from Europa?

I am thinking about moving to Europa.

Like this?

John Mace 01-07-2017 02:55 PM

Quote:

Originally Posted by harmonicamoon (Post 19903510)
What would Jupiter look like from Europa?

I am thinking about moving to Europa.

Better do so before Jupiter leaves the Europa Union.

DSYoungEsq 01-07-2017 02:57 PM

Quote:

Originally Posted by Chronos (Post 19903083)
Ah, right, forgot about phases. While which effect would dominate would depend on the phase, I think the net effect would still be that Earth is usually brighter. But I haven't run the numbers.

Keeping in mind that the distance from Mars to Earth when Earth is at its fullest separation from the Sun is significantly greater than the Earth to Venus distance under the same conditions, of course.

DSYoungEsq 01-07-2017 02:58 PM

Quote:

Originally Posted by John Mace (Post 19903601)
Better do so before Jupiter leaves the Europa Union.

Jupitexit?

Blue Blistering Barnacle 01-18-2017 01:44 PM

How much easier would it be for Martians to deduce Heliocentric system? They would have an easy example of another body with a satellite. They have 2 moons themselves. They would have an extra planet with phases.

How about Kepler's laws?

I'm guessing Europans (at least the ones living on top of the ice) might do quite well.


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