9
votes
Would Jupiter look big?
No, you won't be able to tell immediately, and yes, it will look big.
First, I think it's extremely unlikely that a spacecraft could travel to Jupiter without knowing Jupiter's size.
However, maybe a ...
- 4,655
8
votes
Earth’s Orbit speed and apparent motion question
Firstly, it's going to take a big rocket to do this (larger than any rocket we have built so far btw).
We're travelling together with the Earth, so our speed relative to the Earth is 0. Thus, this isn'...
8
votes
How brightly does Venus's hot surface glow at night? Could you see it? Could you see well enough to walk around?
Keep calm and apply the Planck Distribution Law for radiant heat transfer. Integrated between two different wavelengths and including an emissivity factor of 0.8 (reasonably good for most rocks), we ...
- 8,693
6
votes
Star visibility from space
"The sky is full of stars!"
While not on these three spacewalks, astronauts in cis-lunar have indeed seen stars, and this is documented in transcripts!
From Seeing stars from cislunar space?
...
- 151k
6
votes
Accepted
How far can you see on the surface of Venus?
Apparently you can't see very far, but not because of mist.
The visibility was a pleasant surprise to the scientists who, after
reviewing Venera 8, had predicted a dark, murky and dusty atmosphere
in ...
- 189k
5
votes
Outer space and dark-adapted vision
Answer: Yes and no.
Being in a dark environment (such as dark side orbital transit) will allow the retina to dark adapt. But a half LEO (lasting about an hour) is not long enough duration to fully ...
- 28k
4
votes
How brightly does Venus's hot surface glow at night? Could you see it? Could you see well enough to walk around?
Yes.
For those who are sceptical on theoretical grounds, lock yourself in a completely dark room and wait for dark-adaptation to set in. Plug in a soldering iron and wait for it to heat up; you will ...
4
votes
How brightly does Venus's hot surface glow at night? Could you see it? Could you see well enough to walk around?
No. You could not see by blackbody radiation in either IR or visible regardless of brightness.
To be able to “see” something depends on both brightness and contrast. There may be enough radiation (...
- 28k
3
votes
If you travelled at exactly the speed of light, what would the stars look like behind you?
You would not see anything, which is the same as appearing as if time stopped.
As you approach 1c, the light has trouble reaching you and appears to drop in wavelength, becoming redder, and eventually ...
- 4,655
3
votes
How far can you see on the surface of Venus?
There is no sulfuric acid fog on the surface of Venus. Sulfuric acid clouds, formed in the upper atmosphere when dissociated oxygen reacts with water and sulfur dioxide, rains down towards the surface ...
- 8,693
3
votes
Does Falcon 9's first stage use laser, radar or vision to assist landing?
It uses GPS and, as backup, an intertial navigation system. The two have always provided virtually identical navigation data. A SpaceX employee said that in an interview.
- 5,505
2
votes
Does reflected sunlight from the ISS prevent astronauts from seeing the stars during an EVA?
Answer: Yes and no. It depends on ambient light levels and how they affect the astronaut’s dark adaptation.
On dayside transit, sunlight on ISS structure and Earthlight would produce photopic (light-...
- 28k
1
vote
Visibility of curvature on other planets and moons
Whether a straight line appears straight or curved is highly subjective. It depends on your expectations, and the part of your visual field the line is passing through. Straight lines passing through ...
- 28k
1
vote
Accepted
Have lunar (or martian) rovers exploited shadows, perhaps for terrain comprehension or obstacle avoidance?
This NASA article describes the autonomous driving of the Perseverance rover. In particular, Perseverance is the first rover to use vision for autonomous driving.
But increasingly, the rover will ...
- 48.4k
Only top scored, non community-wiki answers of a minimum length are eligible