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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Why is SWAN dimming?

The SWAN C/2020 F8 comet is passing near the Earth, but from Wikipedia The comet has dimmed a small amount since May 3. It was expected to possibly reach 3rd magnitude in May, but is now expected to ...
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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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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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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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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 do we know that comets definitely mase and not just fluoresce?

Wikipedia's Astrophysical_maser#; comets mentions some anecdotes of notable masers associated with comets, and Maser emissions from comets begins: The 18-cm lines of the OH radical are the only ...
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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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Size and mass of comet ATLAS (C/2019 Y4)

I read some news about this new comet and some unreliable sources said it is twice as big as Jupiter. I tried to find a reliable estimation of its size or mass, but I couldn't find anything. Would you ...
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What makes the coming comet increase/decrease in brightness?

I understand C/1979 Atlas Y4 is potentially going to rapidly increase in brightness and visibility to the point we can see it very well in May-ish, in the Northern hemisphere. I am wondering why it's ...
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Why do all the stars near this comet show up as four separate dots in a row?

After seeing this tweet about our not-so-new but at least newly-discovered "mini-moon" I scrolled down and saw the tweeted image below. Since the object is the known short-period comet 114P/Wiseman–...
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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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Comet 289P/Blanpain sudden outburst?

So Sky Safari has shown that comet 289P/Blainpain has had a sudden increase in brightness, and is currently sitting at mag -1.4!!! Last week it was sitting at +15. It is due to reach Perihelion on ...
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Do comet tails increase as comets move away from the Sun?

Do the tails of comets increase on their return trip from the Sun?
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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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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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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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What makes scientists already so certain that Comet C/2019 Q4 (Borisov) is a comet and not an asteroid?

US Naval Research Laboratory scientist Dr. Karl Battams has recently tweeted Unlike 'Oumuamua, whose asteroid-or-comet nature still gets debated, this one is definitely a comet. If it is ...
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Comet mass loss

As the comet orbits around the Sun, I gather that its tail loses mass due to solar wind and tidal waves. Approximately, from what distance (with respect to Sun) will the mass loss begin?
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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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What's going on in this photo of Halley's comet's tail?

When researching for this answer I was looking at Space.com's 2011 article Photos of Halley's Comet Through History I saw the image below, and read the caption. Halley's Comet in 1910 ...
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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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How uniformly is cometary debris distributed along the entire orbit of the comet?

Meteor showers occur when Earth passes through debris shed by a comet (if I get that right). Does this mean that the entire orbit of the comet is strewn with debris? I suppose that the debris follows ...
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How to see Comet 46P/Wirtanen?

I've got a Celestron Astromaster 114 telescope. I live in Los Angeles and would like to get a look at 46P/Wirtanen. Can anyone tell me when this comet is going to brightest and how best to locate it ...
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very bright object (visible even after sun risen)

Brevard Co. FL. At first I thought it was a comet it appeared to have a tail. Starts out low in the east and gains elevation as the sun rises. As the sun is just above the horizon it is still visible ...
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Is a comet necessarily confined to the solar system?

I had the following question: A comet enters the solar system. Assume that it is influenced only by the Sun, not by any of the planets. Which statement about its orbit is correct? And I chose as ...
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What cosmic disaster is most likely to happen? [closed]

Of all the different ways that the Earth can be destroyed what ways is the most likely that could happen?
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Will comet 21P that just passed Earth on Sept 10 produce Draconid storm on Oct 9?

Comet 21P/Giaccobini-Zinner just made its closest pass to Earth and also made its Solar perihelion on the same day (Sept 10) which is roughly one month ahead of the annual Draconids meteor shower (Oct ...
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Water Content of Space Bodies

In general, are carbonaceous chondrites (CC) or comets more water rich? I know that evidence has suggested that both CC and comets are partly composed of water, but which body is generally more water ...
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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 bright is Comet PANSTARRS C/2017 S3 now?

The LiveScience article Incredible Hulk? Nah, This Glowing, Green Light in the Night Sky Is a Comet published just hours ago discusses Comet PANSTARRS C/2017 S3 and mentions: bright bursts ...
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Would the dynamic pressure of the Sun’s solar wind be strong enough to trap plasma ions within an open container?

If you were to place a long cylinder, open at one end and closed at the other end, and position this cylinder so that the open end is facing the Sun, and then you were to inject plasma ions, such as ...
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Do the cometary gas ions which make up the plasma tail of a comet reach the velocity of the Sun's solar wind?

Do the cometary gas ions which make up the plasma tail of a comet reach the velocity of the Sun's solar wind?
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New NEOs are found daily. Is there any evidence gravity is pulling them to a centralised location?

With all of the new NEOs (near-earth objects) are they being pulled in or are they interacting with each other?
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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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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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when are you able to see Halley's comet, and for how long?

I've been hearing about Halley's comet for a while now, and I'm just curious as to when and where to see it, and for how long. :)
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How often do comet occultations of stars happen?

By travelling to specific places, astronomers can see three thousand star comet transition events every year at m15 for the major (50km+) comets and asteroids averaging about 20 seconds, perhaps that'...
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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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What ever happened to the “Small Comet Theory” of water influx on present-day Earth?

This comment (below the question Is there any new water formed on, or brought to, Earth?) links to the 2002 Article in the New Scientist Was all the Earth’s water brought here by comets? which states: ...
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How do comets and other solar system bodies gain energy to exit the solar system?

I recently learnt that some comets like C/1980 E1 (Bowell) interacted with objects like gas giants in the solar system and gained enough energy to exit the solar system. But from Physics, I know that ...
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Do comets have a limited number of orbits? [closed]

Do comets have a limited number of orbits?
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What documented comet has/had the highest specific orbital energy?

After reading this answer I wondered if there have been document comets with orbits on non-return, hyperbolic trajectories as they approached the Sun. This means that they would not be ...
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Would a direct hit by a small comet be catastrophic?

Would a direct hit by a short-period comet with a 3 mile diameter nucleus cause enough damage on Earth to threaten or destroy human life and the ability to produce crops?
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What would people on Earth see during a close comet pass?

What would people, standing on Earth, see, hear and smell, if a short period comet, with a two mile diameter nucleus, came by at 100,000 miles above us?
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Would a comet break up during a close pass of the Earth

Would a short-period comet, with a 2-mile nucleus, be able to come within 200,000 miles of Earth without breaking up?
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Is it true that Jupiter protects Earth? [duplicate]

I am curious to know whether Jupiter is a reason that we have life on earth as it protects earth from comets, without Jupiter – comets would be more likely to hit us?
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Pluto is fuzed to all the asteroids, comets, other minor planets, etc. Would it be big enough to hold an atmosphere without forming a tail? [closed]

Pluto is fuzed to all the asteroids, comets, other minor planets, etc. Would it be big enough to hold an atmosphere without forming a tail? All minor planets, asteroids, comets, etc that aren't ...
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A question about calculating the radius of a comet

A Comet is orbiting around the sun with period of $T= 5.5$ years. The comet has radius $R$. After 5.5 years (A period) we understand that its radius has decreased about $20cm$. How can we calculate ...
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How large are the effects of nongravitational forces on comet Halley?

The effects of outgassing on comet orbits can be noticeable. Yeomans, in Cometary orbit determination and nongravitational forces, 2004, wrote: As the astrometric datasets improve and lengthen and ...