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1500 questions
15
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What are the large round dark "holes" in this NASA Hubble image of the Crab Nebula?
I came across this image of the Crab Nebula taken from NASA Hubble telescope. What are the large round "holes" and how are they formed?
Martin
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2 answers
Why are most lunar maria on the visible side?
Is there any reason why the Earth side of the Moon has enormous plains and mountains, while the far side contains just few small ones inside largest craters?
SF.
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15
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What percent of planets are in the position that they could be viewed edge-on from Earth? (and thus able to undergo transits)
Star number 12644769 from the Kepler Input Catalog was identified as
an eclipsing binary with a 41-day period, from the detection of its
mutual eclipses (9). Eclipses occur because the orbital plane of the
stars is oriented nearly edge- on as…
Larian LeQuella
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15
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1 answer
What are Trojan Asteroids and where are they located?
Asides from the main Asteroid Belt, there are Trojan Asteroids - what are these and where are they located?
user8
15
votes
4 answers
How did the Earth come to be in orbit around the sun?
I'm not sure if this post should be in the physics subject forum, but this seems to fit here too. I have been reading a book about chemistry and how the universe came to be with the theory of stars creating most of the elements we know of. I began…
bobthebuilder
15
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1 answer
What is the most dense object in the universe?
Inspired by this answer to the question, Why is the Sun's density less than the inner planets?, what is the most dense object in the universe?
8protons
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15
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Mechanisms of binary/multiple star formation
What are mechanisms of binary/multiple star formation in different mass ranges (low, intermediate and high stellar masses)?
user2579566
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4 answers
Why do Earth and moon move apart but binary black holes move closer?
According to the accepted answer on Is the moon moving further away from Earth and closer to the Sun? Why?, the moon is receding from Earth because tidal forces and friction cause energy to be lost.
However, according to LIGO's website,
As the two…
Gnubie
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15
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What is a White Hole?
White holes are purely hypothetical at this point and are considered only because it is assumed something like it could exist as the balance to black-holes.
Reading this article seems mostly writers taking liberties with the information but poses an…
user96
15
votes
3 answers
What wavelength to best detect the "9th planet"?
We know that the reflected sunlight will make detecting the 9th planet very difficult in the visible light. Is there another band that will be more likely to detect it? What is the surface temperature of this object likely to be, and what would that…
PearsonArtPhoto
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Where is Voyager 1 (or 2) going? In which direction?
Knowing it has exited the solar system, is it traveling in the direction of the center of the galaxy, away from it, orbiting it, or maybe even going perpendicular from the disk-shaped galaxy?
Ska
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Why don't we see the galaxy center?
When we look at the sky, and see the Milky Way, we mainly see a band, with no real center.
On a more accurate picture we can guess the center of the galaxy (see this picture), but we still don't see the center as some kind of big bright "star", like…
Thibault
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How quickly does a supernova heat up/expand?
Suppose there's a star out there that's a lot more massive than the Sun.
Suppose further that orbiting this star is a planet not unlike Earth. Water, oxygen, civilization, and all.
Now the star decides to go supernova. How quick, or slow, is the…
Ricky
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4 answers
How long does a sunrise or sunset take?
From the time that the sun appears on the horizon, or meets it on its setting, to the time that it is fully visible, or no longer visible on its setting, how much time passes?
Secondly, is there a place in the world where a sunrise/sunset occurs…
user11308
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3 answers
How hot must a star get before it is considered to be a star?
How hot must a star get before it actually becomes a star? Why does it need to get so hot? Please find an official site to quote from, if you can.
Timtech
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