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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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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4answers
220 views

Is it possible for a virus to come from a meteorite?

So I am not a true scientist and I was just wondering if an extraterrestrial rock from space can have some dangerous unidentified virus or bacteria that can be deadly and wipe out the Earth if it not ...
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3answers
452 views

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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33 views

Does this video catch an Eta Aquarid - Earth skimming meteor?

I did a time-lapse animation looking towards the sunrise from Sydney, Australia on 25th of April. You can see it here around 1m 25s in (that link should jump to just before it appears very near where ...
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1answer
106 views

What was that Asteroid/Comet in the 90s?

I am now in my mid 20s and I remember when I was 6-10 years old, there was a comet or asteroid that flew really close to earth. I remember being able to see the object very clearly as if it were the ...
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1answer
74 views

Why are radar images of comets shaded only on one side?

NASA published a picture of a comet the other day. The image shows the comet being lit from above. See NASA's picture below. However, since it is a radar image, I would have assumed to get a ...
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1answer
103 views

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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1answer
72 views

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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1answer
75 views

How frequently does a comet drastically change its orbit in the Solar System (like 67P did in 1959)?

Comet 67P/Churyumov–Gerasimenko flew by Jupiter at only 0.05 AU distance in 1959. This encounter lowered its perihelion from 2.7 to 1.3 AU (almost becoming an Earth crossing comet). Since it happens ...
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1answer
1k views

Why do comets appear to have a continuous supply of dust?

Comets orbiting the sun have a tail that points away from the Sun, due to the solar wind. (Strictly speaking, a comet can have both a type I tail - ion tail, and a type II tail - a dust tail. This ...
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1answer
79 views

Earth's Versus Catastrophic Meteor

How evasive is the Earth to Catastrophic Meteors? Google says the Earth is approximately 92.96 million miles from the Sun. It also says the suns radius is 432,474 miles. Therefore, it is 93,392,474 ...
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40 views

Are mass extinction events more likely during meteor showers / passing through comet debris?

Meteor showers happen when Earth passes through the debris left by a comet in its orbit. Meteors are generally tiny, like snow flings or pebbles and don't make it to the ground as meteorites. But ...
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124 views

Is it accurate to compare comets to clouds and rain?

I'm trying to avoid an opinion-based question, so before I outline the comparison I'm proposing, I will qualify the specific facts that yield this comparison. By focusing answers on the relative ...
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1answer
92 views

Is there sufficient evidence to confirm additional Planet in solar system

I have watched this scishow episode where Hank says that astronomers believe there is another planet in our solar system. Link He says that it's because how asteroids and comments are being pushed ...
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1answer
75 views

Where is the materials of comet after it crashed into the sun?

If a comet crashes into the sun, where will the substance (eg: water,silicon) be? Will they be inside the sun? Or they will be ejected from sun again?
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1answer
70 views

Why is Rosetta's Comet so “warm”?

Rosetta Comet AKA 67P/Churyumov–Gerasimenko has the surface temperature range of -43 to -93 degree Celsius. Now, if we compare that with the Mercury (I chose Mercury cause it's closest to the Sun ...
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1answer
101 views

Could the trajectories of non-periodic comets be used to infer properties of the 'ninth planet'?

Non-periodic comets are comets which have very long orbital periods (>200 years or more), spending most of their time in the outer solar system. Planet X, recently revived by researchers at Caltech, ...
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3answers
114 views

If sun steals comets from other stars, then what is the primary source of comets?

I heard some theory that sun may steal materials such as comets from neighbouring stars, is it true? But if is true, what is the primary source of those comets? Especially "who" creates them instead ...
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1answer
249 views

Have we ever observed a body, such as a large asteroid, “hitting” the Sun?

Some other SE questions about launching ICBM's into the sun got me wondering whether we have ever observed an object on a path that intersected with the Sun? How close did it get?
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3answers
1k views

What is a dead comet?

How is a Dead Comet different from the normal comet? How are they formed? And why is the Halloween asteroid 2015 TB145 called a dead comet?.
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1answer
45 views

Do sungrazing comets leave a field of meteoroids near the Sun?

A large fraction (a third?) of all comets found (with observational bias thanks to SOHO) have been sungrazers, breaking up with perihelion of a few of Sun's radius. Is there reason to believe that ...
2
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1answer
35 views

What does oxygen on comet 67P/Churyumov-Gerasimenko mean?

Recently, the Rosetta mission found oxygen on the comet 67P/Churyumov-Gerasimenko. According to theories, oxygen should not be in the state in which it is on the comet. What are the previous theories ...
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1answer
452 views

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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1answer
169 views

Did a piece of Halley's comet strike the Earth 1,500 years ago?

A friend showed me an article saying that there's evidence that a piece of Halley's comet may have struck the earth about 1,500 years ago. Is anyone here aware of such evidence?
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0answers
45 views

Review Content for my Comet Infographic

I've been hard at work in recent months on an infographic that details the anatomy of a comet... I'm a graphic designer and this is a fun little side-project of mine. It's only quite basic in terms of ...
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0answers
32 views

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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1answer
195 views

Lack of planets in the Oort Cloud

With the current news about the possibility of a planet in the Oort cloud, I was thinking, why is the matter in the Oort cloud distributed so? It makes sense that inside the planet region there is not ...
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2answers
81 views

Is there a mechanism that makes small moons more rounded than comets?

67P/Churyumov–Gerasimenko has a highly irregular dumbbell shape. But the sample of comet shapes observed is very small, so I wonder if irregular shape is the norm for comets and for small moons. Many ...
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1answer
61 views

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 ...
3
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2answers
76 views

Is any meteorite known to come from a comet?

Comets are mostly icy but they should have some rocky components too, right? I wonder if there's any rocky piece of a former comet among collected meteorites. Is it possible today to identify a ...
6
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1answer
274 views

How can Halley's Comet be predictable?

How can we know that Halley's Comet is going to come again every 76 years? I understand that the comet has an orbit around the sun but how can scientists know that it won't be thrown off course for ...
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4answers
12k views

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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1answer
75 views

How much time comet is within the Earth's orbit? [closed]

Comet on the parabola orbit flies by Sun. I would like to know what is comet's full energy? What is its distance from Sun at perihelion?
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1answer
299 views

What is the direction of a comet's dust tail before and after perihelion?

I recently created a visualisation of comet ISON's orbit. However, I received a critique that the dust tail of the comet should be pointing away from the Sun after perihelion. As far as I know, the ...
6
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1answer
150 views

How often are new astronomical objects (variable stars, supernovae, comets, etc) discovered by amateurs?

How often are new astronomical objects (variable stars, supernovae, comets, etc) discovered by amateurs? Where could one report new findings?
3
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1answer
91 views

Why did Earth need material from comets to assemble the raw materials for life?

It's often speculated that matter from comets played a crucial role in the development of life on Earth. For example, Maps of Time says, Many of the ingredients of the early atmosphere (including ...
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2answers
155 views

How did water get on Earth

I recently read that water more then 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 then an atomic bomb. ...
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2answers
2k views

Is C/2012 S1 (aka ISON) the fastest comet on record to-date?

This source may be nebulous (no pun intended!) for some. It writes to say Starting at around 95,000mph at the start of this month, Comet ISON will eventually reach an astonishing 845,000mph on ...
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1answer
40 views

Where does the dust on 67P/Churyumov-Gerasimenko come from?

As we (laymen) are told, comets lose gas and dust when they descent into the denser regions of the solar system. Seemingly so much and so large parts that they can even cause meteor showers like in ...
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1answer
394 views

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? Just curious! Thanks in advance!
3
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1answer
85 views

landing on a comet is more important than landing on an asteroid?

Philae landed on comet 67P this year. And it means a big breakthrough for the science and technology of human being. However Hayabusa mission of Japan not only landed on an asteroid but also returned ...
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2answers
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Why do comets come from our local Oort cloud instead of from interstellar sources?

Comets form where stars form. And they are then ejected by the orbital changes of giant planets. But why are they ejected to form specifically a local Oort cloud instead of going interstellar and ...
2
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1answer
68 views

Do/did the asteroids contain enough water to create Earth's oceans?

It seems from the recent Science paper by Altwegg et al (2014) that the commonly accepted source of Earth's water being the comets might not be (completely) true. Their study suggest that the water in ...
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2answers
143 views

Could the Philae comet lander be recharged by laser?

Could the Philae comet lander be recharged with a laser (or possibly many lasers) from earth? My thought would be to aim one or more powerful lasers from earth at the Philae lander to recharge it ...
5
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2answers
138 views

How does 67P rotate?

What can be said about 67P/Churyumov-Gerasimenko axial tilt? Is it fixed (if so, at what value), only changing with precession (at what rate?) or does 67P "tumble" with axial tilt changing over time? ...
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2answers
565 views

Why all the photos from 67p are black and white?

I was wondering why every picture we saw on internet about Rosetta's landing on 67p just black and white ? Is there something i should know ?
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1answer
819 views

Classification of a Comet

Google's definition of a comet is: a celestial object consisting of a nucleus of ice and dust and, when near the sun, a ‘tail’ of gas and dust particles pointing away from the sun. This ...
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1answer
113 views

Why does Jupiter break comets apart?

I understand that there are magnificent tidal forces that come with getting too close to Jupiter, but what is causing comets like Shoemaker-Levy to get torn apart? I wouldn't expect that the ...
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1answer
84 views

Companion Sun the cause of comet impacts with Earth

On television, I heard a scientist who believes that our Sun has a companion (brown dwarf) Sun, that is responsible for comets destroying life here on Earth every 26 million years. He proposed the ...
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2answers
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Is Mars expected to go through the tail of Comet Siding?

This question will likely be answered "in retrospect" in about 8 days. So it's a great opportunity to "lay it out there" and then let reality prove you right/wrong. On the 19th of October, Comet ...