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 a depleted comet and an asteroid?

When a periodic comet flies by the Sun enough times, it can become depleted of its volatile elements. Once it is depleted, what distinguishes it from an asteroid, other than records of past sightings ...
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What meteor shower has the radiant that appears furthest west after sunset, and why?

When it finally gets answered, answers to How to calculate the position of a meteor shower's radiant point based on its associated comet's orbit? will help us understand why the radiant points ...
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What determines if a comet's debris will produce periodic meteor showers?

Background I was wondering if the debris from the comet NEOWISE that recently passed Earth would provide meteor showers in the future. I looked up that the Perseid meteor showers happen when the Earth ...
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Where is the Perseids meteor shower coming from?

Swift–Tuttle Comet has orbital period of 133.28 years. Yet, people say that debris and dust from this comet causes this meteor shower. This does not make any sense. Or do they want to say that from ...
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Has any of the orbiters or rover on Mars captured image of comet NEOWISE?

We are seeing stunning pictures of comet NEOWISE from earth (and ISS too), are there any pictures captured from Mars by an orbiter or rover, or any other spacecraft?
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Can a single impact event trigger a runaway greenhouse?

Somewhat related to this question: Is the Earth going to evolve towards Mars' fate or Venus' fate? Human civilization may be fragile, but life itself is extremely resilient, with extremophiles and ...
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How long can the comet C/2020 F3 (NEOWISE) will observed with the naked eye or small optics?

In the answer to the question Where should I be looking to see Neowise in southern Sweden? there is a picture with the comet positions till 30 July. In other sources I saw similar pictures also with ...
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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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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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Is there evidence for galactic “seasons”?

The Solar Year has huge effects on our climate, and the signs of passing seasons are physically evident on Earth. I recently learned about the Galactic Year. To my understanding, our sun orbits the ...
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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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Seeing comet NEOWISE?

Today the NY Times published an article that explained how to see NEOWISE at night. The article explains it like this: To catch NEOWISE yourself, look up at the northwest skies about an hour and a ...
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Comet Neowise c2020 f3 will return in ~6800 years, how can we be sure Earth will be in the right place to see it then?

I have read in several places that the orbital period of comet Neowise c2020 F3 is about 6800 years. In several popular media sources it is said that we will be able to see the same comet after ~6800 ...
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Why Comet C/2020 F3 Neowise returns even it's orbit is near- parabolic?

I have read in Wikipedia about Comet C/2020 F3 Neowise that it's orbit is near-parabolic. But in another section, it says that it is a non-periodic comet whlith orbital period ranging from 4500 years ...
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Will NEOWISE be known as the Great Comet of 2020?

Many or all comets visible to the naked eye are referred to as Great Comets of their year(s). Might NEOWISE too be called like this? Why or why not? Is the IAU responsible for declaration of Great ...
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If Planet Nine is a primordial black hole could it explain 'Oumuamua and Borisov's orbits without them being interstellar?

There has been an increasing amount of interest in the possibility of primordial black holes and that Planet Nine may be one itself. Planet Nine is a potential explanation for the orbital ...
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Is Neowise viewable from my position?

I have had an impossible time trying to locate this comet. My lat/long is 38.3/-82.4. My elevation is 705ft. The application that I'm using shows me exactly where Neowise is supposed to be (North East,...
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Blue color of ion (plasma) comet tails

What exactly is the cause of blue light of ion (plasma) tails of comets? Somewhere I have read that the source of blue light are CO+ ions which has just acquired the missing electron and became ...
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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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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 ...
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1answer
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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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1answer
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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 ...