Most Popular
1500 questions
11
votes
1 answer
How do you figure out the magnitude of stars?
How do you figure out the star magnitude of a star? Do they just give it a guess or what?
If not, how do they figure it out accurately?
Jamd
- 377
- 1
- 2
- 7
11
votes
5 answers
Where to obtain Tycho Brahe's data?
I would like to obtain Tycho Brahe's data on Mars. What would be an authoritative source? One source I could find is this page (the data is given as an Excel file) but I have no idea can that be trusted. Does some astronomical organization or…
brahe
- 111
- 1
- 3
11
votes
2 answers
Why aren't brown dwarfs the dark matter?
There seems to be not enough matter to account for the fact that the speed of some stars located far from the Galaxy center is almost the same speed as those stars found nearer to the center of the Galaxy, therefore it seems there should be even…
user6760
- 2,503
- 16
- 30
11
votes
4 answers
Does the mass of the observable universe ever change?
First do we have anyway to even estimate the mass of the entire observable universe? And then is there any data that shows mass being gained or lost? Would we ever know if someone was playing with the til.
Also I want to be clear that I am not…
blankip
- 231
- 2
- 6
11
votes
2 answers
How did water get on Earth
I recently read that water more than likely got here by comets (carrying water) hitting the Earth. However it also it says the impact of a comet hitting the Earth is much greater than an atomic bomb. So if comets brought water to Earth how was it…
TheDudeAbides
- 351
- 1
- 3
- 5
11
votes
1 answer
Why haven't asteroid belts turned into new large bodies?
If gravitation (attraction of mass) is the cause of the formation of all celestial bodies then how come the numerous small bodies found in asteroid belts spread over an orbit instead of clustering together ?!
WaterBearer
- 219
- 1
- 3
11
votes
5 answers
Does the Sun turn around a big star?
The Moon orbits the Earth.
The Earth orbits the Sun.
Does the Sun orbit another bigger star?
If so, does this star orbit, in turn, a very big star?
... etc ...
What are all the intermediate subsystems up to motion around the center of the Milky…
Sebastien Palcoux
- 341
- 2
- 9
10
votes
2 answers
Are there more stars than all the words ever spoken by humans?
A while ago I saw Neil deGrasse Tyson comparing the number of stars in the universe with the number of words spoken by all of humankind, ever since.
I realize both of these numbers are not strictly defined, but still, we can use our best…
Jens
- 769
- 5
- 23
10
votes
2 answers
Can moon set after being up when due north? (pseudo circumpolarity)
I'm in the northern hemisphere, facing north, and notice that the moon
is due north (azimuth 0) and is still above the horizon, albeit barely.
Does this mean the moon is necessarily circumpolar (doesn't set), at
least for the next few hours?
As…
user21
10
votes
1 answer
Appearance (frequency) ranking of stars?
Is there some ranking / statistics that shows how common given type of celestial objects is? A table that would allow the answers to questions like: What type of star is most common per volume of our galaxy? Are white dwarfs more common than red…
SF.
- 6,259
- 2
- 26
- 53
10
votes
1 answer
How are the newly discovered Janus/Epimetheus rings different from the other rings of Saturn?
What are the newly discovered ring systems of Saturn, and the circumstances relating to the discovery? Is there something that makes them different from the old well-known rings, like their formation?
The ring in question is the Janus/Epimetheus…
Sawarnik
- 211
- 1
- 5
10
votes
2 answers
What is the current estimation for how much time the Sun will function properly?
Eventually, the Sun will run out of fuel, go dark, and other bad things will happen. About how much long is it predicted that we will have a sun functioning as it is currently?
user19
10
votes
3 answers
Can the supernova remnant SN 1572 be observed by amateur astronomers?
The SN 1572 remnant, also called Tycho's supernova remnant, is beautiful in X-ray images. It seems to be rather dim in visible light. Are there any amateur photographs of this object? How long are the exposure times needed to get a nice picture?
Arne
- 2,293
- 15
- 24
10
votes
1 answer
How much mass does an object in space need to keep a human on its surface?
Assume there were a roughly spherical object in space like a meteorite or a comet.
If I weighed 80kg on Earth, how much mass would be required for an object in space so that I could stay on its surface without "flying away?" It's not necessary have…
Sergei Basharov
- 203
- 2
- 6
10
votes
1 answer
What is the process for vetting the 4,175 candidate planets Kepler has discovered?
In the National Geographic article about NASA's announcement of new planets discovered by the Kepler spacecraft, it states that there are 4,175 candidate planets. What is the process for vetting these candidate planets? How do we know they exist…
user5291