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21 votes

What is this celestial phenomenon in the video?

That is a re-entry of an artifical satellite, or rocket body. (As Darth Pseudonym mentions, its actually the upper stage from the Soyuz MS-25 launched two days earlier). It's certainly not a comet. ...
James K's user avatar
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9 votes

What is this celestial phenomenon in the video?

Objects that shed a lot of bits like that and move relatively slowly are usually human-made space junk from low-earth orbit that has slowed down enough to reenter and burn up. It's definitely not a ...
Darth Pseudonym's user avatar
6 votes

What is this celestial phenomenon in the video?

As James K said, that's no comet. ;) 12P/Pons–Brooks is a relatively bright comet, but it's certainly not that bright. On 2024-Mar-26, JPL updated the trajectory data for this comet, which has ID ...
PM 2Ring's user avatar
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6 votes

Does the Oort Cloud lose mass with time?

The Oort cloud objects are only very loosely bound to the Sun. That is, their total energy (kinetic plus gravitational potential) is only just negative. That means you only need a slightly positive ...
ProfRob's user avatar
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6 votes
Accepted

How much mass did the Late Heavy Bombardment add to Mars?

Alessandro Morbidelli has kindly consulted me on this topic. He said: "The late veneer on Mars is approximately equivalent to that of the Earth, from the abundance of highly siderophile elements ...
Michael_1812's user avatar
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5 votes
Accepted

Extinction Level Event (Asteroid Impact Hypothesis) Likelihood Equation

Knowing that there are X asteroids that could threaten is not in itself useful. What you want to get is a event rate, the probability of something happening per year. One oversimplified way is to ...
Anders Sandberg's user avatar
5 votes
Accepted

Are there interactive maps for comets?

Unlike an eclipse, which is only visible for a specific area and at a specific time (which can be predicted in advance), comets can be seen over a wide area of the globe and often for several weeks or ...
James K's user avatar
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4 votes
Accepted

What is the difference between an Active Asteroid and a Jupiter Family Comet?

Active asteroids are (as far as we can tell) comets in every respect except that they're inside the asteroid belt, and Jupiter-family comets are comets that stay inside Jupiter's orbit but aren't in ...
Darth Pseudonym's user avatar
3 votes
Accepted

Comet and eclipse

Fairly common. Comets will reach their maximum brightness near to the sun, and so in the days before space-based searches for comets and asteroids, it was possible for a comet to have travelled ...
James K's user avatar
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3 votes
Accepted

the difference between the heliocentric and the geocentric

Yes, the difference is exactly that. The precise meaning here cannot be determined with certainty, it is a matter of convention. With meteors (and their parents bodies in this context) true geocentric ...
Martin 'Kvík' Baláž's user avatar
3 votes

3rd brightest ever object in the sky

The brightest star-like object is probably Supernova SN 1006. With object before the time of modern photographic techniques, one is dependent on descriptions, and these can be hard to interpret when ...
James K's user avatar
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2 votes

What is the difference between an Active Asteroid and a Jupiter Family Comet?

As per Wikipedia: Active asteroids are small Solar System bodies that have asteroid-like orbits but show comet-like visual characteristics i.e. they show a coma, tail, or other visual evidence of ...
Nilay Ghosh's user avatar
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2 votes
Accepted

Cooling the early earth

Nice hypothesis. However impacts from comets, thought they are made of ice won't cool it down, rather if the nucleus survives from the intense heat, and crashes down, it will convert a lot of kinetic ...
Arjun's user avatar
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2 votes

the difference between the heliocentric and the geocentric

Yes, the difference is a difference of coordinate systems. The Earth moves with respect to the sun, and velocities depend on the choice of coordinate system. In your particular case, it seems likely ...
James K's user avatar
  • 123k
2 votes

Calculating Ephemeris from JPL Osculating Element

In the osculating elements for 2023-12-24, the period of 1.9513×108 seconds is 6.183 years, or 71 days shorter than the 6.378 year period in the elements for 2014-03-31. An encounter with Jupiter, 0....
Mike G's user avatar
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