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Is the ISS vibile from Mars?
The bluddy question is stuck in anthropology and YA won't let me move it to astronomy. Apologies for that.
I just asked the question for a bit of fun, but fighting YA to get anything done makes it not!
Finally. In astronomy. And yes I meant to say "Is the ISS visible from Mars". Meaning through a telescope. For argument sake lets say up to an aperture of about 20 inches. It;s been so hard to do this "fun" question, it would have been easier to do the calculation myself!
Finally. In astronomy. And yes I meant to say "Is the ISS visible from Mars". Meaning through a telescope. For argument sake lets say up to an aperture of about 20 inches. It;s been so hard to do this "fun" question, it would have been easier to do the calculation myself!
12 個解答
- 匿名4 年前
Without doing actual calculations, it is easy to answer with a resounding no. It might be bright from Earth, 250 miles altitude, reflecting the Sunlight against a dark sky, but even the observing conditions are such that it would not be visible from Mars- even if it were much much brighter.
PS: I do mean with very powerful telescopes.
- Satan ClawsLv 74 年前
When people come here and ask "why can't "they" build a powerful telescope and look at the landing sites on the Moon?", the usual explanation is about how the resolution limit prevents that. For an object that is 150 (at best) to 1000 times over the distance but is only about 20 times as wide ... well, I think you have the answer.
Anyway, let's put some numbers in: a 200 meter object at a distance of 50 billion meters makes up for an angle of atan(200/50e9) = 2.3e-7 radians. For visible light (about 500 nanometers),
https://en.wikipedia.org/wiki/Angular_resolution#E...
you need a tube around 40 meters wide. Good luck finding a telescope that size (and operating it in a reliable way)! And we're talking about separating power -- accumulating enough light to be registerable is a new problem!
- 4 年前
Two answers.... First, it would be lost in 'Earth shine', as Earth's reflected light from the sun would drown out any hope of seeing it - even in a fairly powerful telescope.
Second... YES - if Earth were to suddenly disappear - it *could* be visible, but you'd still need a telescope - with it's very reflective surfaces and solar panels, it would be a bright speck in a telescope (that would need to have 500x magnification or more...)
- spot aLv 74 年前
The ISS is not visible from Mars. You could see the moon from Mars with a pair of binoculars. Mars is a tiny disc in our sky. Can you see Olympus Mons on Mars from earth? It is the biggest mountain in the solar system and much bigger than the ISS.
Hubble cannot even see the lunar landers on the moon from only 238000 miles away
PS you can't use binoculars or telescope on Mars since you have to be in a space suit. The atmospheric pressure is similar to the pressure on earth at 100,000 feet and the Martian atmosphere is toxic to humans
- ?Lv 74 年前
No. The ISS is only about the size of a football field, and orbits the much MUCH larger and brighter Earth.
- MorningfoxLv 74 年前
The ISS is about 72 x 108 meters. Mars is at least 55 million km from Earth (and the ISS), so to see the ISS as anything more than a dim dot, you would need a telescope aperture of 460 meters. Even if the ISS aimed a powerful laser at Mars, it would still be a single brighter dot.
The largest visible-light telescope on Earth will be the European Extremely Large Telescope, at 39.3 m, still under construction in Chile.
20 inches = 0.51 meters.
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A 20-inch telescope could just barely resolve a separation of 80 km (50 miles), for small bright objects on a dark background. Don't know how that would work for the ISS next to a much larger Earth, with a diffuse terminator line, but I think that you could detect that something about 90 meters in size was orbiting about 300 km above Earth. You would also need a very sensitive CCD camera, because the human eye couldn't see anything that dim that was "visible" for only a few minutes.
And that introduces another problem .. you don't want to point a sensitive, expensive telescope anywhere near to the sun. It would burn out the camera in a fraction of a second.
- 4 年前
N. The resolution of a 20-inch telescoppe would not permit seeing the ISS from that distance. Take a search for "telescope resolution" and do a little arithmetic. You'll see it isn't possible even when Mars is closest to Earth.