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18
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2 answers
What are the differences between matter, dark matter and antimatter?
I thought dark and anti matter were kinda the same, but after saw a video, they mention that dark matter is not antimatter but their explanation is a little fast so I got doubts.
What are the differences between matter, dark matter and antimatter?…
Alex Sifuentes
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1 answer
How did New Horizons take such well-lit pictures of Pluto?
The photos of Pluto from New Horizons are truly beautiful.
But considering that Pluto is so far away from its nearest start - our Sun - how is it so well lit up?
Did the New Horizons have a massive flash mounted on its camera to illuminate the…
CodyBugstein
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18
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1 answer
Is there any telescope on Earth that can see the lunar rovers on the Moon?
If I have the right numbers, it seems to me that even the Hubble telescope might barely be able to make out a carcass of a blue whale on the surface of the Moon, which puts objects as small as the lunar rovers or the American flag left there during…
Mark Bailey
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6 answers
Moon's orbit around the Sun
The Earth revolves around the Sun and the Moon revolves around the Earth.
Out of curiosity I started thinking about the orbit of the Moon around the Sun and expected (assumed) it to be as follows:
But on Wikipedia and some other sites I found out…
Umang Chaudhari
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18
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1 answer
Are there any alternative explanations for the gravitational force we attribute to dark matter?
It always seemed counter-intuitive to me that we observed an measured a gravitational force and since the universe has not enough mass to account for it, the conclusion was to say there's a different kind of matter wich doesn't interact with…
Eduardo Serra
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18
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8 answers
Determine the moons of Jupiter through a telescope
I was doing my own "space exploration" last night with a telescope. Being a space noob I can't visually determine stars or planets (I know the moon, though), but I focused on one particularly bright one when I saw 4 smaller "stars" on each side.…
Coomie
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17
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2 answers
How many galaxies have been discovered?
I know Andromeda is our nearest galaxy. But how many known galaxies have been discovered and what are they?
Unicorn
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17
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1 answer
How are the photos of the Milky Way taken?
We are inside the Milky Way, right? So, how are we able to take photos of the Milky Way?
M.Tarun
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17
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2 answers
What is radiation pressure and how does it prevent a star from forming?
This is a follow up to: Is there a theoretical maximum size limit for a star?
The answer there talks about the radiation pressure preventing a star from forming.
What reaction is causing this radiation pressure and why does this potentially…
user96
17
votes
4 answers
What is the upper and lower limit of temperatures found on stars?
What are the most extreme temperatures (both hot and cold) stars have been detected at? Is there an upper and lower limit for the detected temperature of stars?
user8
17
votes
4 answers
Is it possible to break apart a neutron star?
I was inspired by this question on Physics, as well as this question right here on Astronomy. Neutron stars are tightly bound together as neutron degenerate matter. They're very massive and have a strong gravitational field. Is it possible to break…
HDE 226868
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17
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1 answer
Timescale of ignition of a protostar?
What is the timescale of start of nuclear fusion as T Tauri type star transforms into a Main Sequence star?
Wikipedia article on T Tauri type stars mentions:
Their central temperatures are too low for hydrogen fusion. Instead, they are powered by…
SF.
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17
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2 answers
What reason is there to doubt the existence of the hypothesised planet Tyche in the far distant solar system?
Please note, I do not necessarily believe in its existence, just after a scientific (hence, non-Wikipedia) reasoning to doubt the planet's existence, other than the "we would have seen it" argument. I am, nor are the articles below, referring to…
user8
17
votes
2 answers
Do the orbits of planets change sometimes?
Do planets sometimes wobble and get off their paths? What if an asteroid were to hit it?
Timtech
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17
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2 answers
What is the largest recorded solar flare?
For the purposes of this question I would interpret the word "recorded" as loosely as possible meaning that historic records such as ice cores or tree rings would count. Also what effect did such a large flare have on life on Earth at the time?
ehsteve
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