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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Do astronomers generally agree that the distinction between comets and asteroids is not so clear?

edit: I just saw this tweet and find it incredibly relevant :) begin question: See this answer and then consider if there are known or likely solar system bodies that might be identified as both ...
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What makes some meteor showers continue for days, while the “Unicorn shower” can be shorter than one hour?

The Washington Post's One hundred meteors in 15 minutes? ‘Short-lived outburst’ of shooting stars forecast for Thursday night. says: A “short-lived outburst” is forecast for Thursday evening around ...
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Why do particles from a comet that result in meteor showers spread out mostly along the comet's orbit?

My understanding of the meteor showers that repeat yearly is that the Earth passes through the orbit of a comet that is nowhere near us, and might not even exist anymore, yet it's orbit is filled with ...
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Why are these objects moving at Vastly Different Speeds along the same orbit?

UPDATE: The on-line simulation seems to be working beautifully now! I'd recommend anyone to go back and take another look to enjoy both the mathematical beauty of orbital mechanics, and the aesthetics ...
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Why would the Perseids meteor rate fall off after maximum faster than the increase before maximum?

Writing about the 2018 occurrence of the annual Perseids meteor shower, the EarthSky.org Astronomy Essentials article Start watching for Perseids now says: People tend to focus on the peak mornings ...
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How to calculate the position of a meteor shower's radiant point based on its associated comet's orbit?

Below this answer to Why are Delta Aquariids “for the southern hemisphere” while the Perseids are “for the north”? I wrote the comment: +1 To make this complete, ...
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What is the difference between asteroids, comets and meteors?

Some celestial objects seem to be referred to as asteroids, some as comets, and some as meteors or meteorites. What is the distinction between all of these different objects? Are any of them the same?...
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What (actually) is Jupiter doing to this year's Perseids meteor shower?

After reading the Astronomy Magazine article Perseid meteor shower set for its best show in nearly 20 years and NASA's Look Up! Perseid Meteor Shower Peaks Aug. 11-12, I understand that Jupiter's ...
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Why did the Comet Shoemaker-Levy-9 fragments cause such large explosions on Jupiter?

In July 1994, the comet Shoemaker-Levy 9 (D/1993 F2) tidally fragmented and these fragments collided into Jupiter, as per the image below. Image source The question is, what mechanisms resulted in ...
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Is this object an asteroid or comet, and how can it produce so many tails?

The NASA Hubble Space Telescope Science Release HEIC 1320 - When is a Comet not a Comet? - Hubble astronomers observe bizarre six-tailed asteroid is self-explanatory, but it doesn't explain what ...
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What's the fastest moving object in the universe?

We know that nothing can have proper velocities larger than the speed of light in vacuum. But are there any objects in space that get close to it? Any comets, or other objects thrown by gravity or ...
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Could the dinosaurs have seen the asteroid that killed them?

Wikipedia says the Chicxulub impactor is thought to have been a 10-15 km diameter object. Would it have been visible to a (human*) naked eye before impact? And if so, would it have appeared like a ...
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How can comets have tails if there's no air resistance in space?

I understand that solar radiation causes material to vaporize out of a comet into dust but why does the dust then trail behind the comet like a "tail"? Assuming gravity is the only applied force ...
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How is the path of an asteroid calculated?

How do scientists and astronomers recognize the perfect path or orbit (if it's orbiting an object) of an asteroid or a comet?
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Can two comets travel together as one?

If two comets come together in space, will they bounce apart, merge into a single body, or could they travel together through space, either touching or orbiting a shared center of gravity?
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Does Jupiter help to protect the Earth against comets/asteroids impacts?

Does Jupiter help to protect the Earth against comets or asteroids impacts? Some astronomers believe that one reason Earth is habitable is that the gravity of Jupiter does help protect us from some ...
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How long does a comet “live”?

When a comet loses all his volatile material after many orbits around the Sun, it becomes a "dead" comet (like an asteroid, a centaur or whatever), see for example 2015 TB145. Is there any ...
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Any record of the Earth passing through the tail (not trail) of a comet?

Discussion below the Space SE question How hard is it to fly through the tail of a comet? Has it been done? has led me to ask if there is any record of the Earth passing through the tail of a comet. ...
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What comet's tail did Earth pass through before Halley's?

This answer to Any record of the Earth passing through the tail (not trail) of a comet? mentions Earth passed through the tail of Halley's Comet in 1910. It caused a bit of a panic due to claims that ...
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Does the loss of mass create an observable change in a comet's orbit?

Comets lose their mass through water evaporation due to close encounter with sun, so my question is does the loss of mass create an observable change in a comet's orbit? What kind of change that may ...
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What were they expecting to see when Halley's comet appeared in 1910?

This answer to Any record of the Earth passing through the tail (not trail) of a comet? mentions Earth passed through the tail of Halley's Comet in 1910. It caused a bit of a panic due to claims that ...
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Questions about Hubble's brand new view of an interstellar comet (video)

This GIF is made (via giphy.com) from the new NASA Goddard video Hubble's New Image of Interstellar Object and if I understand correctly many (if not all) of these frames are from https://archive....
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Have meteor showers been predicted for planets or solar-system bodies other than Earth? Have attempts been made to detect them?

Per the linked Q's and A's in Why do particles from a comet that result in meteor showers spread out mostly along the comet's orbit? and it's answer, meteor showers happen on Earth when it passes ...
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Roughly what fraction of comet orbits that intersect Earths' orbit result in known meteor showers?

Per the linked Q's and A's in Why do particles from a comet that result in meteor showers spread out mostly along the comet's orbit? and it's answer, meteor showers happen on Earth when it passes ...
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Which measurements have shown that 2014 MU69 is red? (New Horizons' next target)

The recent NASA feature article New Horizons: Possible Clouds on Pluto, Next Target is Reddish MU69 is actually the smallest KBO to have its color measured – and scientists have used that data to ...
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How big do comets get?

If my understanding is correct, Chury, the best explored comet so far is rather on the smallish side as comets go. Most comets observable with naked eye were so because they flew close to Earth, not ...
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The creation of comets

How are comet and meteors made, and what causes them to travel through space so fast? I have tried researching, but I decided this was the faster way.
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What calculations show that Comet Shoemaker-Levy 9 orbited Jupiter for several decades before its spectacular impact? (Chodas, Sekanina & Yeomans)

This answer to A moon in eccentric orbit dipping below Roche limit includes the following about Comet Shoemaker–Levy 9 Here is a nice figure of its last passes: I looked up "fragment A" in ...
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Can a comet orbit a planet?

Given that moons commonly orbit planets, why do we never encounter a comet orbiting a planet? What would happen (exactly, in detail) if a large one did settle into a stable orbit around the Earth? ...
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How far away would a supernucleus comet be visible?

If an instrument like LSST quickly spots something as soon as it reaches magnitude 24½, how far away would a 60km first-time visitor from the Oort cloud be when it is spotted? I'm thinking that a ...
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Did comets 266P/Christensen or P/2008 Y2 (Gibbs) cause the Wow! signal?

Continuing my fascination with the Wow! signal, I stumbled upon an article from 2016 titled Famous Wow! signal might have been from comets, not aliens. It describes the hypothesis that the signal ...
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Long term development of Comets

When an exocomet passes by our Sun in a trajectory that leads it to establish a Solar Orbit what eventually happens to it? In addition to its original inertia and vector being altered what are the ...
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How did water get on Earth

I recently read that water more than likely got here by comets (carrying water) hitting the Earth. However it also it says the impact of a comet hitting the Earth is much greater than an atomic bomb. ...
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Do some comets spin? If so, how fast?

The GIF below is copied from my question earlier What might a CN filter be in the context of comet watching? Is it showing dust, or gas, or something else? where I'd said: In this post on the website ...
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Calculating distance of comet C/2019 Y4 (ATLAS)

SO, I decided I would take some pictures of the comet C/2019 Y4 last night. Afterwards, I thought I would try and do a rough estimation of distance based on my observations. I don't have any fancy ...
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What is the closest an asteroid or comet has passed the Sun and survived?

After SOHO began watching the Sun from space with its coronagraphs 24/7 it was discovered that there are comets passing very close to the Sun quite regularly, and while some are destroyed, some are ...
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Halley's Comet current location in sky and visibility?

I am an amateur in astronomy, but recently I wonder if it is possible to see (in a photo, maybe, if not in a telescope) Halley's Comet when its not close to earth. If there is such photo, how I can ...
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Why is the “green” comet C/2014 Q2 (Lovejoy) red in this picture?

In this nice NYTimes 'survey article' "Our Vast Solar System and Its Many Explorers" there is a NEOWISE image of Comet C/2014 Q2 (Lovejoy). See here also. The NASA description of the image says: ...
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Leonid meteor showers and the Tempel-Tuttle comet

I've been reading about the Leonid meteor showers and am struggling to understand one piece of information. On Wikipedia (Tempel-Tuttle), it states: The orbit of 55P/Tempel–Tuttle intersects that ...
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Where should I be looking to see Neowise in southern Sweden?

I'm in the south of Sweden and just spent over an hour trying to find Neowise, but didn't see it. I live in a rural area, there are no lights nearby and there is a small hill with clear visibility ...
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Can we measure comets in a similar way to exoplanets?

A 2km comet at 40AU's can dim a sun sized star at 100 light years by 3%, and a 10km comet can cause an eclipse (is that right?) So would 2,3,10 km objects be easy to measure via star dimming if we had ...
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Fastest recorded apparent motion of a comet or asteroid seen from Earth (degrees/day)?

If I've done my maths correctly in this answer comet 2I/Borisov (C/2019 Q4) was seen to move about 0.2 degrees in 7 hours, which is almost 0.7 degrees per day. I'm assuming this is pretty rapid ...
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Why are Delta Aquariids “for the southern hemisphere” while the Perseids are “for the north”?

In the video How to spot Comet NEOWISE, plus the largest 3D map of the Universe | Night Sky News July 20 after 05:28 Dr. Becky (Smethurst, Oxford astrophysicist) ...
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I'd like to photograph NEOWISE from Los Angeles, what is the optimal time?

I live in Los Angeles and have a camera adapter for my telescope -- nothing fancy just an Astromaster 114. What is the optimal time, in terms of dark sky and bright comet, to take a photo of Comet ...
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What is the probability of an astronomical body hitting you?

It appears that there is already a calculated ballpark for meteor fatalities, but what about other factors such as space trash, comets, and other miscellaneous items in space? Is it possible to ...
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How significant are the recent results that Scholz’s Star has perturbed several observed hyperbolic objects?

The Gizmodo article A Visiting Star Jostled Our Solar System 70,000 Years Ago refers to the the three year old ApJ. paper The Closest Known Flyby of a Star to the Solar System (also arXiv) which ...
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Can a supernova or a close passing star create a transient sun gravity focus “habitable zone”?

This question was inspired by the previous question Would a black hole passing next to a star create a deadly focal point due to gravitational lensing?. I understand, as gravity also acts on light, ...
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How is Comet SWAN C/2020 F8 doing? Will it become easily visible by eye?

The New York Times article How to See Comet SWAN in Night Skies says: Astronomers have their fingers crossed that the comet will keep brightening in the coming weeks as it heads north, passing 52 ...
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Is there an alternative (potentially easier to understand) Euler diagram of the new solar system body classification?

note: This question is asking for a representation of the astronomical classification scheme now used for solar system bodies as established (presumably) by the Working Group for Planetary System ...
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Can I calculate the apparent position of comet NEOWISE C/2020 F3 from a topographic position with Skyfield?

I'd like to get .altaz(next_several_weeks) of this comet from Skyfield and .separation_from() other planets. It reads the JPL ...