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1500 questions
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Doesn't gravity attract objects in space until they collide?
If the formula to calculate the force of gravity between two objects is:
$$F = GM_1M_2/r^2,$$
why do planets stay in orbit? Or is there another formula at work?
CharlieK
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What is the distance that the Moon travels during one orbit around the Earth?
Also, does it always take the same amount of time, or does it fractionally differ on each revolution?
Asadullah Ali
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How many sun-like stars are there in the universe?
After yesterday's announcement of the Kepler telescope finding a huge amount of newly observed exoplanets, i saw a headline claiming that as much as 22% of sun like stars in the universe have planets in their habitable zone. There are loads of stars…
bogen
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Why doesn't Earth's axis change during the year?
My understanding is that the Earth's axis points in the same direction in space during its entire orbit around the sun. And this is what causes our seasons.
My question is why doesn't the axis follow the orbital path (kind of like a car driving…
rmaddy
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Why is Jupiter's Great Red Spot reddish?
The Great Red Spot is a persistent anticyclonic storm, 22° south of Jupiter's equator. Why is it reddish?
From Wikipedia:
It is not known exactly what causes the Great Red Spot's reddish color.
Are there updated data?
rnrneverdies
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What would the effects be on Earth if Jupiter was turned into a star?
In Clarke's book 2010, the monolith and its brethren turned Jupiter into the small star nicknamed Lucifer. Ignoring the reality that we won't have any magical monoliths appearing in our future, what would the effects be on Earth if Jupiter was…
Maelish
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Is there any point on earth where the moon stays below the horizon for an extended period of time?
When I was teaching a class why the earth has seasons today, I mentioned how the poles of the earth experience months of daylight and darkness. Then one of my students asked whether the moon disappears as well.
Using an orrery and a string, we…
Kupyn
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"Next Generation Arecibo Telescope (NGAT)... would combine a 314-metre-wide platform with a swarm of 9-metre dishes on top" What would that look like?
In Nature News' August 11, 2023 Closing down an icon: will Arecibo Observatory ever do science again? found in The Observatory there is discussion of the Next Generation Arecibo Telescope (NGAT):
Another, more distant hope is for the Next…
uhoh
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JPL Horizons sending too many emails
I submitted a job that, I think, should have returned 100 emails from JPL Horizons.
I now have over 6000 emails and they are coming in at about four a minute.
Anyone else had this problem?
Anyone know how to stop the deluge?
I have emailed JPH…
Haywire
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Approximately what percent of the sky has nothing in it?
From my persepective here on Earth, the sky seems to look like a few large-ish things and a bunch of tiny things. Hubble teaches us that even the apparent void between the tiny things has many very tiny things. Stuff that is very near takes up a…
Him
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Is there enough matter orbiting the sun to make a second sun?
I read somewhere a long time ago that there is enough matter in our solar system in the form of rocks and dust to create another sun.Is this correct? Was our solar system trying to create a 2 star system?
user48394
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3 answers
Is the power output at the core of the sun about the same as a compost pile (about 300 watts)?
I read an article at abc.net.au saying that the power output of the sun is about 276.5 watts per cubic metre, similar to that of a compost pile.
A compost pile is not incandescent, while the sun is. It's so hot that it glows. So I have a hard time…
Sedumjoy
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Counting from the 21st century forward, what place on Earth will be last to experience a total solar eclipse?
All coordinates on Earth are equally likely to experience a solar eclipse, so it's just a matter of luck where the Moon's shadow happens to fall. But some place has to draw the short straw and be the last in line to experience a total solar eclipse.…
user177107
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Do Schwarzschild black holes exist in reality?
Do Schwarzschild black holes exist in reality? I have searched answer for this question but am not fully satisfied. Everything in the universe, including planets, stars, and galaxies, is spinning. How can something nonrotating/non-spinning exist in…
apk
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Is the center of our galaxy, the Sagittarius A* black hole a former star?
If a black hole comes from a dying star, do we have a record or proof that our galactic center was once a huge ball of burning plasma? I'm not an astronomy student.
TheRobloxGamer
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