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1500 questions
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Is there an O1 or O0 star?
Okay, we've seen the super hot Wolf-Rayet stars, especially WR 102 and 142, and the "slash stars," many of which are early O (O2-4.5/WN). We know the temperatures of these Wolf Rayet stars. So if we know that, what would their spectral types be in…
WarpPrime
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How bright is it on Pluto in the middle of the day?
I just saw a documentary about New Horizons and Pluto with plenty of photos New Horizon had taken of Pluto. All these photos were very bright, like Earth would be during the day. Considering the distance between Pluto and the sun I suspect the…
d-b
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When was the last volcanic eruption on Mars?
There are several volcanoes on Mars, including Olympus Mons, the largest volcano in the solar system, the volcanoes on the Tharsis bulge,... But they are all thought to be inactive now.
When did the last volcano erupt on Mars?
usernumber
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Why are the time zones calculated as 360°/24 and not 361°/24 or 360°/23.933?
Background: I'm training to be a geography teacher. Currently I have practice lessons and I'll be discussing solar time and standard time with the class. Now I stumbled over an issue to which I could not find an answer:
We teach the…
mfran
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How to calculate the movement of the object passing near other object in space?
Assume object A is moving through the space and is passing near the other object (B). Assume the gravitational influence of other objects can be ignored. How to find the equation describing the movement of the object B?
There are 2 cases, object A…
Danubian Sailor
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6 answers
Did I see a supernova explosion?
I think I just saw a supernova explode with my own eyes through my GSO 12 inch Dobsonian. Please tell me what it was! I am still trying to find what it was it was mindblowing!
I went out on my roof around 18:20 (New Delhi, India) and was looking up…
Saurabh Arora
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11
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Are there stars with an average density greater than the central density?
Are there likely to be stars for which the average density is greater than the density at the centre? Intuitively, I would say not, as density tends to decrease outwards, but ideally I would appreciate a clear mathematical justification for this.
wrb98
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If Sunlike stars become a red giant and eventually a white dwarf, what do red dwarfs become?
The Sun is said to become a red giant at the end of its life (before that it will become an orange subgiant first and then an orange giant or so) and after ejecting its outer layers it should become a white dwarf. If yellow dwarfs like the Sun…
Giovanni
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Which stellar properties can we describe as "first principles" in which we can derive the rest?
Mass, size, temperature, luminosity, chemical composition, the initial abundance of the molecular cloud, distance, brightness, age, and evolutionary cycle can all be used to characterize a star. A star's brightness is dependent upon its distance and…
Astroturf
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How many satellites orbit their planet faster than the planet rotates?
Phobos is so close to Mars that it orbits Mars much faster than Mars rotates. This means that it rises in the west and sets in the east, even though its orbit is prograde.
Are there any other known natural satellites that orbit their planet faster…
usernumber
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11
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2 answers
Does Saturn raise tides on Titan's lakes?
Titan is the only body in the Solar System other than Earth to have large bodies of surface liquid. Since Saturn is much more massive than the Moon, I would expect for tides, if they're present to begin with, to be much larger than the ones here on…
ChristieToWin
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1 answer
How large were the deviations of Uranus's positon from predicted which led to the discovery of Neptune?
After Uranus was discovered and its orbit calculated, its future orbit was calculated, and its future positions as seen from Earth were calculated.
And observers of Uranus began to notice that Uranus was deviating from its calculated positions. …
M. A. Golding
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3 answers
Why are telescopes positioned in Lagrange points?
In this Wikipedia article about the list of space telescopes to be launched (which I assume is exhaustive), of the 11 telescopes yet to be launched, 6 will be positioned at the Sun-Earth L2 Lagrange point. Why is that so?
I read that it has…
user30617
11
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1 answer
Was the "green star" event in NGC 3314 ever figured out or named?
from NGC 3314 Variable Object by By Bill Keel (University of Alabama, Tuscaloosa) and Lisa Frattare (Hubble Heritage Project, STScI). The object in question is circled.
Comments below this answer led to Dust in Galaxies which shows the image of…
uhoh
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Why is there no concavity in the orbit of the moon around the Sun?
Such questions have been asked here and I have read the answers some of which are quite informative. However, I want an answer that's straightforward.
I have gone through the following paper by A B Turner titled The Moon's Orbit Around The Sun.
In…
ThePhysicist
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