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Questions tagged [comets]

Icy bodies that usually consist of methane, water, and other materials that originate from beyond the jovian planets, and occasionally fall into the inner solar system giving off a massive tail as material is boiled off.

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

Yeah, obviously one is an asteroid and one a comet, duh; but what does really differentiate them? I've read that active asteroids have an asteroid-like orbit, but what does that mean? Thanks in ...
jack_O'Dim's user avatar
3 votes
3 answers
3k views

What is this celestial phenomenon in the video?

Some news channels published a video of an unusual phenomenon. The description says it's Comet Pons Brooks, but the comet looks completely different. There are other videos of this kind on YouTube, ...
Vladimir Orlov's user avatar
0 votes
2 answers
92 views

the difference between the heliocentric and the geocentric

Is the difference between heliocentric and geocentric velocities a matter of the coordinate system? Or are these kinds of velocities different? For example, the speed of a comet at perihelion is 71km/...
Robert's user avatar
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1 answer
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Calculating Ephemeris from JPL Osculating Element

I've built some open source software that calculates Ephemeris from JPL osculating elements to simplify imaging and tracking of Comets, Asteroids, and Near-Earth bodies. This works very accurately a ...
George Hilios's user avatar
3 votes
1 answer
155 views

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

How much mass was deposited on a terrestrial planet during the Late Heavy Bombardment (LHB)? Is it possible to estimate a reasonable interval, specifically, for Mars? Could the mass addition to Mars ...
Michael_1812's user avatar
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3 votes
1 answer
361 views

Extinction Level Event (Asteroid Impact Hypothesis) Likelihood Equation

We have the Drake Equation that calculates the probability of intelligent ET (extraterrestrials/aliens). Since the asteroid impact hypothesis has been more or less accepted as the cause of the K-Pg ...
Hudjefa's user avatar
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1 answer
66 views

Are there interactive maps for comets?

As we know there are interactive maps for lunar and solar eclipses. This is the interactive map of October 14, 2023 annular solar eclipse from timeanddate, and you can zoom in to see the eclipse path ...
Snack Exchange's user avatar
4 votes
1 answer
187 views

Comet and eclipse

It seems likely the 12P/Pons-Brook comet will be visible at the same time as the 2024-04-08 American eclipse. How unusual is this and what can science say about what will appear? What other historical ...
David's user avatar
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1 answer
378 views

Does the Oort Cloud lose mass with time?

Can blocks of ice escape from the Oort cloud and away from the solar system forever?
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3 votes
1 answer
153 views

Cooling the early earth

My son had this theory that the icy comets cooled the hot earth during the late heavy bombardment. What do we know about this cooling effect on the early evolution of the earth? He intended his theory ...
user442920's user avatar
0 votes
1 answer
99 views

3rd brightest ever object in the sky

What’s the 3rd brightest ever recorded object in the sky? For example Venus is normally the 3rd brightest object in the sky. However there have been the occasional comet or Supernova that have ...
blademan9999's user avatar
1 vote
1 answer
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Calculating Comet Position at a Given Julian Date with Available Orbital Elements

I have some orbital elements for comet P/2004 R1 (McNaught) from this dataset and I would like to calculate its position around the sun (x, y, z coordinates where the sun is at the origin) at a ...
Ege Can's user avatar
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1 vote
0 answers
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Are short-period comets more stable (in their orbits) than long-period ones?

Why the sharp distinction between short-period (P) comets of less-than-200-year orbits and those (C) with even slightly longer ones? To explore the possibility that it has to do with stability, I will ...
Kurt Hikes's user avatar
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3 votes
1 answer
71 views

Most accurate way of measuing the radius of a rubble-pile comet in an N-body simulation?

I have written an N-body simulation (close to finished) in C++ which focuses on the tidal disruption of comets. I allow comets to be constructed in 2 ways: Via my HCP (hexagonal-closest-packing) ...
Gregor Hartl Watters's user avatar
2 votes
0 answers
37 views

What is the best estimate for the radius of Shoemaker-Levy 9?

I have been digging through various scientific articles on modelling the breakup of SL9 to attempt to ascertain its intial size, yet the various estimates vary tremendously. A radius of 700 m - 1000 m ...
Gregor Hartl Watters's user avatar
4 votes
0 answers
43 views

How commonly observed is H2 forming in H2O ice, among comets?

How common is H2 forming under a shell of normal ice, among comets? The context is the Oumuamua discussion, and its latest tentative solution. "Acceleration of 1I/‘Oumuamua from radiolytically ...
Mark Besser's user avatar
11 votes
3 answers
4k views

How is Halley's comet still in one piece?

According to the first answer of This question parts of Halley's comet hit the Earth every spring as part of the Eta Aquarid meteor shower. If this is true, then how is the comet still in one piece? ...
Deko Revinio's user avatar
21 votes
2 answers
6k views

How do we know that a comet passed by earth 50,000 years ago?

This article (https://gothamist.com/news/a-green-comet-is-sailing-over-new-york-and-earth-for-the-first-time-in-50000-years) claims that a comet will pass by earth soon for the first time in 50,000 ...
coco's user avatar
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16 votes
2 answers
3k views

Is it possible that the Rosetta orbiter moved the comet when it crashed?

Rosetta Comet Orbiter (RCO) crashed into the surface of a comet after the comet passed near Jupiter, which would be out-of-range for its antenna to communicate with Earth. So, the ESA made the ...
Deko Revinio's user avatar
8 votes
3 answers
336 views

How do we know that ice from the S1094b event was from Mars surface and not from the impactor?

The recent news story NASA’s InSight Lander Detects Stunning Meteoroid Impact on Mars, about an impact that occurred on Mars on December 24, 2021 (event S1094b), shows a picture of the impact crater, ...
Jean-Marie Prival's user avatar
3 votes
1 answer
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Time of comet at perihelion query

In Practical Astronomy With Your Calculator Or Spreadsheet by Duffett-Smith and Zwart, the authors write (in relation to calculating cometary positions): The longitude of the comet is not usually ...
Peter's user avatar
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4 votes
2 answers
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Could a rogue comet perturb a frequently occurring meteor shower to the extent that debris falls on Earth...and dislodges satellites?

This is for a work of fiction that I started five years ago. Clever people from Astronomy Stacks answered several questions for me back then. Now that I am in the final edit of this manuscript, I find ...
Evelyn 's user avatar
3 votes
1 answer
140 views

If a supernova explodes all it's comets into space, can they reach a big number of star systems?

If there's DNA life that arises on a warm planet 2 billion years after the big bang, and meteorite collisions on the planet propagate DNA unicellular organisms into millions of icy rocks orbiting the ...
bandybabboon's user avatar
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3 votes
1 answer
163 views

calculating MPC orbital uncertainty parameter U

I'm trying to understand how the orbital uncertainty parameter 'U' introduced by the Minor Planet Center (MPC) is actually calculated for minor bodies. This wikipedia page gives the formulae to be ...
mysterium's user avatar
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0 votes
2 answers
219 views

Comet Bernardinelli-Bernstein; could it be a "planet-killer" and what could prevent it from getting close to us?

The huge "mega" comet C/2014 UN271 (Bernardinelli–Bernstein) 80 miles wide is coming towards Earth from the edge of our Solar System. It is supposed to only get to the middle of our Solar ...
Peter U's user avatar
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1 vote
1 answer
139 views

How is a comet visible when far from the Sun

The latest news tells of a super large "mega" comet C/2014 UN271 (Bernardinelli–Bernstein) approaching the Solar System in about 9 years. It must be very far from the Sun, so how do we ...
John Canon's user avatar
5 votes
0 answers
36 views

How to model the kinematics of gases expelled from comets and planetary atmospheres?

Once the ices of comets sublimate, where do they move to, and with which equations do you describe their motion in the interplanetary medium? Similarly, where do the gases that are stripped from the ...
Astrolien's user avatar
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3 votes
1 answer
116 views

What exactly did ALMA observe at 20 AU from the "Mega Comet Arriving From the Oort Cloud" that will pass in 2031?

Gizmodo's Mega Comet Arriving From the Oort Cloud Is 85 Miles Wide says: For the new study, Lellouch and his colleagues used the Atacama Large Millimeter Array (ALMA) in Chile to refine the comet’s ...
uhoh's user avatar
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1 answer
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What is going on with comet C/2021 A1 Leonard? Is it going to be bright this weekend or not?

I have to plan an excursion to try to find clear evening skies to try to see if we can spot comet C/2021 A1 Leonard about 10 to 15° above the ocean in the Southwest after sunset this weekend. I'm ...
uhoh's user avatar
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12 votes
1 answer
929 views

How close to escape velocity are most Oort-cloud comets?

User @antlersoft wrote a nice answer to my question on the difference between barycentric and heliocentric models of the solar system when applied to comets (edge cases of the systems). In a comment, @...
WarpPrime's user avatar
  • 6,673
7 votes
2 answers
749 views

What is the difference between barycentric-centered and heliocentric-centered coordinates?

When talking about celestial bodies orbiting the sun with a decently circular orbit or small aphelion, the heliocentric orbital parameters are almost identical to the barycentric parameters. However, ...
WarpPrime's user avatar
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1 vote
0 answers
104 views

What observational data was there that comet Leonard C/2021 A1 might have been dimming and/or breaking up?

Space.com's Comet Leonard, the brightest of the year, is fading and acting strange seems to be full of inexact language, like "something's wrong" and "unhealthy" and "goner&...
uhoh's user avatar
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2 votes
0 answers
216 views

Make a guide map to comet comet Leonard C/2021 A1 using Skyfield

Sky and Telescope's How Bright will Comet Leonard Get? includes the skymap and projected (possible) light curve for comet Leonard C/2021 A1 that will potentially reach +4 magnitude this month. It has ...
uhoh's user avatar
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2 votes
0 answers
57 views

Specific impulse of cometary outgassing?

Note: This question is related to Average DeltaV applied to a comet during outgassing? Rocket engines have a parameter called "specific impulse," which is the measurement (in seconds) of how ...
WarpPrime's user avatar
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1 vote
0 answers
54 views

Average DeltaV applied to a comet during outgassing?

Comets' orbits often change during perihelion passage due to the outgassing of volatiles. So I am wondering, how much change in velocity is applied each perihelion pass? What does this depend on?
WarpPrime's user avatar
  • 6,673
4 votes
1 answer
150 views

Role of aerobraking in cometary orbits?

I'm doing some research about comet perturbations, and have noticed that the outbound aphelion is often different from the inbound aphelion, particularly due to the gravitational influence of the ...
WarpPrime's user avatar
  • 6,673
0 votes
1 answer
97 views

The Kuiper Belt and Oort cloud [closed]

How come the comets and asteroids in the Kuiper belt and Oort cloud are kept in a gravitational field and they don't get pushed and pulled by the planets around them? I get why comets in the Oort ...
Anonymous RU's user avatar
4 votes
1 answer
347 views

Why haven't we had an "asteroid attack" until now?

We know that there is a big and dense ring of asteroids between the orbits of Jupiter and Mars and also "Trojans" and "Greeks" in Jupiter's orbit too. We also know that there are ...
Gamin8ing's user avatar
1 vote
2 answers
767 views

Is there any chance Comet Bernardinelli-Bernstein could collide with Earth?

At a size of 100 kilometers, this comet is ten times the one that exterminated the dinosaurs on Earth. It is headed towards our Solar System and expected to arrive in 2031. It is projected to swing by ...
Peter U's user avatar
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3 votes
1 answer
77 views

Disk-resolved vs disk-averaged photometry?

I have already read this question about the difference between disk-integrated and disk-resolved photometry. But what exactly is the difference between disk-resolved and disk-averaged photometry? I am ...
lazerlini's user avatar
1 vote
0 answers
78 views

Astronomic objects (and their distribution functions) appearing in an old computer game?

Many decades ago, when I learned coding, I was also reading a (red) book on the programming the 8080 processor which was full of code listings and their description. I was in particular fascinated by ...
B--rian's user avatar
  • 5,616
4 votes
1 answer
139 views

Mass loss rate in a typical visible-from-Earth comet

What is the typical range of a comet's mass loss per second to its dust and gas tails, while it is naked-eye visible from Earth? I'm aware this is going to be a very broad range and expect it to cover ...
BenRW's user avatar
  • 153
2 votes
0 answers
56 views

How does a comet crumble? Are there models for that?

Edit: Initially, the title was How does the crumbling sound? I am curious how comets degradate or even disintegrate over time, in particular while they are close enough to the Sun to have tails. Is ...
B--rian's user avatar
  • 5,616
4 votes
2 answers
494 views

Whether the comet is moving in an elliptical or hyperbolic orbit around the sun?

The time of observation after the first observation (in years), the distance between the earth and the comet (in AU) and the angle between the sun and the comet (in radians) is given. How to find ...
Haris Ansari's user avatar
2 votes
1 answer
106 views

Details about the next big comet 2014 UN271?

The announcent of the massive trans-Neptunian object 2014 UN271 to be a comet is rather new (June 22nd, 2021) and really exciting. That comet is rather huge (~100km diameter) and "falling toward ...
B--rian's user avatar
  • 5,616
1 vote
0 answers
36 views

Dotted line of moving objects observed on May 5th and May 12th [duplicate]

I saw a dotted line shooting star-like object May 5th and May 12th. It was longer than any meteor/shooting star tail or trail I've ever seen before. I mean longer in every way, the distance it ...
Kelly Ries's user avatar
2 votes
1 answer
64 views

Is scattering efficiency of dust related to albedo?

I know that the scattering cross-sections of dust in comets depend on the scattering efficiency. A higher scattering efficiency leads to an increase in brightness. Therefore, does it mean that this ...
prody's user avatar
  • 88
3 votes
1 answer
52 views

I have a question about the wording in a paper about a planetary system and comets

I was reading a paper. This is the paper: https://arxiv.org/abs/2006.01711 (https://ui.adsabs.harvard.edu/abs/2020MNRAS.496.4979D/abstract In the method section in the second paragraph there is a bit ...
programmingWolf's user avatar
0 votes
2 answers
187 views

Does this galaxy resemble the Milky Way, and is it relatable as the "template" for the Milky Way?

Taking a look at this photo of comet 2I/Borisov and a background galaxy (2MASX J10500165-0152029): And compare it to this rendition of the Milky Way: The two galaxies slightly resemble each other. ...
WarpPrime's user avatar
  • 6,673
0 votes
2 answers
241 views

A comet orbits the Sun in the same plane as Earth's orbit

If the Earth around the Sun follows a practically circular orbit of radius equal to one astronomical unit, determine its orbital speed in astronomical units per year. If the Earth around the Sun ...
Albert Wesker's user avatar

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