Most Popular
1500 questions
23
votes
3 answers
If we replaced the Moon with Ceres, how close would Ceres have to orbit to cause the same tides?
How close to Earth would Ceres have to be to cause tides of the same strength as by the Moon, above the region it orbits? Ceres has 1.3% the Moon's mass, but that doesn't mean it must be at 1.3% the Moon's distance, right? Is it even possible for…
John
- 1,538
- 6
- 16
23
votes
3 answers
When did people first measure that the Earth was closest to the Sun during January?
When we talk about the reason for the seasons, we usually have to dispel the misconception that seasons are caused by being close and far away in the Earth's elliptical orbit.
And usually, we mention that the Earth is actually closest to the sun…
David Elm
- 403
- 3
- 10
23
votes
2 answers
Is Jupiter a failed star?
The elemental make-up of Jupiter is about entirely hydrogen and helium, along with a very small fraction of the atmosphere being made up of compounds such as ammonia, sulfur, methane, and water vapor. These elements are dominant in stars, so how…
Ammanuel
- 359
- 3
- 5
23
votes
2 answers
What observations can be expected on LIGO if any when Betelgeuse goes supernova?
What observations can be expected from the LIGO† gravitational wave observatory if and when Betelgeuse goes supernova?
Would we know that Betelgeuse has gone supernova before we see it light up our night sky?
†or any other current or soon-to-be…
Lord Loh.
- 339
- 2
- 6
23
votes
3 answers
Help understanding this unsettling image of Titan, Epimetheus, and Saturn's rings?
The NY Times article Saturn’s Rings Are Sculpted by a Crew of Mini-Moons is really interesting and links to the recent paywalled paper in Science Close Cassini flybys of Saturn’s ring moons Pan, Daphnis, Atlas, Pandora, and Epimetheus
But I…
uhoh
- 31,151
- 9
- 89
- 293
23
votes
1 answer
Why do some planets have rings?
Some planets, specifically Jupiter, Saturn, Uranus, and Neptune in our solar system, have planetary rings.
Why do some planets have rings? How are they made and from what? Most importantly, will I be able to observe the rings on any planet with an…
user96
23
votes
2 answers
Why is the Hubble Telescope in space?
Why is the Hubble Telescope in space?
Do we get enhanced clarity and range by placing it in space?
What can it achieve from space that it could not achieve from Earth?
user96
23
votes
2 answers
Is our sun in a star cluster?
Sorry for the absolute begginer question here, but is our sun a part of some globular cluster?
It is something related to Virgo supercluster?
Max
- 417
- 1
- 3
- 11
23
votes
3 answers
What would happen to a polished marble statue left in space for a million years?
Consider it doesn't collide with any other objects. Would it be preserved perfectly in the vacuum or would its surface be damaged by anything like UV rays, radiation, gas, space dust, etc?
Denis Agarkov
- 247
- 2
- 3
23
votes
5 answers
Is Io a magic energy machine?
Io gets its volcanic heat from being flexed by Jupiter's gravity, and this seems to go on forever. That sounds like a magic energy source, since Jovian gravity is perpetual and Io seems to remain in orbit perpetually. Have we discovered magic?
FranklyT
- 239
- 2
- 3
23
votes
1 answer
Why is the Sun's atmosphere (the corona) so hot?
The visible surface of the Sun is 6000 degrees Celsius but the gas in the solar corona is at least 1 million degrees. What heats the solar corona?
ehsteve
- 1,164
- 8
- 14
23
votes
6 answers
What is the minimum mass required so that objects become spherical due to its own gravity?
Is this minimum mass known? or maybe, is it given in terms of density? If so, how much density is the minimum to have an spherical object due to its own gravity?
Clausia
- 785
- 1
- 6
- 10
23
votes
3 answers
Maximum spin rate of a black hole?
I have just been watching a podcast called "Deep Astronomy" and the discussion was about a super fast spinning black hole discovered with the NuSTAR space observatory. This black hole was modeled with high confidence to be spinning at about 99% of…
Jack R. Woods
- 2,932
- 1
- 12
- 25
23
votes
1 answer
How are the compositional components of exoplanet atmospheres differentiated?
How are exoplanetary atmosphere compositional spectra distinguished from those of the parent star(s), from the composition of the planetary surface or any other factor? Is it actually possible to determine the atmospheric composition precisely…
user8
23
votes
1 answer
Milky Way Galaxy from Earth
I've seen a lot of beautiful pictures of the Milky Way from Earth such as this:
...but I can't understand what the cloudy ribbon at the bottom the horizon is. Is it a super-large nebula? Or is it due to the Gegenschein? What happens in the ribbon?
shortstheory
- 445
- 5
- 9