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The newly discovered comet NEOWISE has been given the name C/2020 F3. What is the meaning of the F3 and the C in this name?
The new comet C/2020 F3 was first spotted by NASA's NEOWISE satellite in March 2020.
It is now visible in the NE sky just before dawn. The C may refer to it's non-periodic nature (so far). What does the F3 mean in its name ? The orbit may be…
Thomas
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Is it safer to be near a star or a black hole?
If a star or black hole neared the solar system, which would do the least damage? For the sake of a good comparison, lets assume the candidate star is an "average" 5 solar mass star, and the black hole is a 5 solar mass black hole. My thoughts at…
Jonathan
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What will it finally take to accurately measure the distance to Betelgeuse?
Comments below What is the maximum distance measurable with parallax? discuss challenges associated with parallax measurements of Betelgeuse and link to Wikipedia’s Betelgeuse; Distance measurements which contains the intriguing paragraph:
In 2008,…
uhoh
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Are there neutron stars whose magnetic axis and rotating axis are the same, and if so what will happen?
I know that there's probably a higher chance of having a neutron star that has its magnetic axis inclined to the rotational axis rather than having it perfectly aligned.
If they are not aligned, the neutron star will create beams of radiation that…
space nerd
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What is the probability of seeing a neutron star as a pulsar?
Pulsars are neutron stars that emit a beam of electromagnetic radiation that is not aligned with its rotation axis. If the Earth passes through that beam of radiation, we see a pulsar. Pulsars are only observable if the beam crosses the observer's…
usernumber
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Is there an online planetarium where the observer is on another celestial body?
I know about in-the-sky.org and its online planetarium feature, but that's from the Earth's perspective. Is there a planetarium (preferably online but if not, that's fine) where the observer is on another celestial body, like the Moon or Mars?
Star Man
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How would the sky look if Earth orbited a red giant at a safe distance?
Let's say that instead of the sun, we have a red giant, but are orbiting it at a safe distance, within the goldilocks zone. Would the sky actually look more red? Or would it be closer to white/transparent due to a shortage of blue light for Rayleigh…
Andrej Butić
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Has great eyesight been necessary for astronomers?
In a different (but somewhat related) field, some baseball stars have been known to have "baseball eyes." That is, an exceptional ability to visually follow the trajectory of a 90+ mph baseball to a degree enjoyed by 0.1% (one in a thousand) of the…
Tom Au
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A Sky Map of Gravity - what would it look like?
PREAMBLE
Sky Maps exist which show the distribution and intensity of electromagnetic radiation received on Earth at various wavelengths. An obvious form is a map of the stars (Star Chart).
Maps have also been made for the distribution/intensity of…
steveOw
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Characteristics of the first planets in the Universe?
What would have the very first planets looked like, based on their most likely chemical compositions?
For example:
Were they mostly grey gas giants with atmospheres of hydrogen and helium, coalescing around the first Population II stars?
Were they…
Dave Jarvis
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If the moon wasn't receding from Earth, what would be the impact on the weather and tides?
Moon is slowly receding from Earth, which means that after its formation it was much closer to the Earth than now. How would weather look like if it wasn't receding at it would be now as close as at the beginning?
Surely, the tides would be much…
Danubian Sailor
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Does blackhole merging break their event horizon segregation?
So far as I know, if we have 2 blackholes A and B, both having their own event horizons, then what's inside the event horizon of A remains completely unknown to us, and same for what's inside the event horizon of B.
Now, suppose A and B coalesce…
Xenos
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Why different specifications for telescopes and binoculars?
Sorry for the noob question but I don't seem to be able to find the answer on the internet.
I've been looking through some telescopes and binoculars and noticed that shops typically give different specifications for the two groups. For example, for…
Kamil S.
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Line of lights moving in a straight line, with a few following
My husband and I have just seen a line of about 15 lights moving in a straight line, quite high above the cloud level with a gap, and then 5 lights, a gap, another few, a gap, 1 light, a gap, and a few more.
They were moving at the same sort of…
Sue Melvin
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Infalling observer could never cross Black Hole event horizon?
I have an interest in cosmology, but I would no way consider myself an expert. It would be great if the more knowledgeable contributors would be able to answer the question I have posed.
The intense gravitational field near a black hole causes time…
John Davies
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