Comets Definition and 36 Threads

TL;DR Summary: Can comets either one or many create simultaneously overlapping impact craters for higher air pressures to breed algae and plant life as a micro climate? Is there a depth limit to crater creation on a planet? Let’s say Mars for a depth of 30km can it be done? Assuming the...

(This is a history of science question, so please let me know if it's not appropriate to this forum.) When did someone first realize that major Earth impact events (asteroids, etc.) could potentially be catastrophic? To be clear, I don't mean in the purely theoretical sense (the likely given...

Could someone please tell me if I'm on the right track with understanding this. The periods of the comet and Uranus is different because of Kepler's second law? Is it because planets orbit the sun in a circular path whereas for comets it's a highly elliptical orbit? Thank you.

I was reading about comets and know they come from the Oort or Kuiper Cloud. However, being composed of materials, comets that continually orbit the sun shed the substance that makes them up and, from what I've read, will only thus last for thousands, maybe tens of thousands of years. I know...

Hi! I have read that cometary nuclei have a very low albedo, even lower than coal or asphalt. Because of this, they absorb lots of light and heat rather than reflecting them. So I was wondering how hard is it to detect extinct comets. Could the solar system be full of dead nuclei buzzing around...

Homework Statement The orbits of the planets remains extremely stable over long times however this not always true for comets. Can you explain why not? What hazards might they encounter during their travels? Homework Equations None The Attempt at a Solution I think that due to the comet's not...

A big part of water on Earth come from comets at the very early ages of Earth so I suppose that the comets has same age as the Earth. The Earth and other objects come from a waste after creation of the Sun. The Sun come from cloud of hydrogen and helium mostly. It is star of 3rd-generation so I...

This article has a different spin on how water came to Earth. https://www.newscientist.com/article/2118993-Earth's-water-must-have-arrived-here-earlier-than-we-thought/ The arrival of water on our planet wasn’t a last-minute job. Water came to Earth on icy comets after most of the planet and...

Be on the lookout for Comets 252P/LINEAR and P/2016 BA14 https://in-the-sky.org/news.php?id=20160315_18_100 http://www.skyandtelescope.com/observing/p2016-ba14-closest-comet-in-almost-250-years03162016/ https://in-the-sky.org/solarsystem.php?obj=78283 252P/LINEAR is about perihelion.

Just having a think about comets this morning . Im guessing the tails associated with comets are fragments of rock and ice from the surface of the comets but what is causing them to come off the surface if the comet is traveling through no medium to cause a force to move the bits that a make...

Comets have high Deuterium to Hydrogen ratios. They are enriched with extra neutrons. Comets periodically plunge close to the sun. And, the sun generates flares, which generate neutrons. Separately, I wonder if those neutrons come from fusion of solar corona gas, trapped on magnetic field...

Wikipedia says "Cometary nuclei are composed of an amalgamation of rock, dust, water ice, and frozen gases such as carbon dioxide, carbon monoxide, methane, and ammonia.[" I don't see where the rock comes from. In my mind, rock can be formed from dust only by application to lots of heat and...

Comets have what is called an "induced magnetosphere". Has anyone been able to document polarity in any of the observed comets magnetic fields yet ? If they have I'm curious how it relates to the orbital plane of the comet. I haven't been able to locate that info if it exists so just...

I see this comet being chased by ESA, they said it is presently about 500 million km from the sun. That puts the radiation received by that comet at about 10% (roughly) as what we receive on Earth, well at least on top of the atmosphere, at 1355 watts per meter ^2. Looking at the size of...

The popular press has been alive lately with stories of asteroid interception and even asteroid recovery. Has there been any thoughts of a spacecraft closely approaching a comet? How big are they? How fast do they travel? Is it remotely possible using existing technology? Could we land on...

How does Jupiter "protect" Earth from comets and such? I've commonly heard that Jupiter protects Earth by flinging comets out of an orbit that would otherwise leave them heading for Earth. I understand that Jupiter can throw comets and other objects out of their current orbit when they pass by...

Recently, I attended a lecture at my university entitled "The Life and Death of a Star-Grazing Comet" presented by John Raymond, an astrophysicist at Harvard Smithsonian. In this lecture, he talked about Comet Lovejoy and how it allowed us to help study the corona of the sun. As the comet was so...

Hey all, I haven't been alive for that long, so I guess my data probably isn't as good as it should be, but in my experience there have been far more noteworthy comets appearing only to the southern hemisphere, and not to the northern one. In fact, I haven't ever seen a comet (since I was a...

I've gotten into an amusing discussion with another individual on the topic of the apparent size of comets as seen in SOHO satellite images of Sungrazing or Sun-impacting comets. I won't go into the crackpot conspiracy theories I've heard, but will instead ask: why do these tiny comets appear so...

Suppose a large, 'dirty snowball' comet, 25-50km in diameter or more, were to hit Mars at some speed, say 75,000 km/h. I am quite certain it would vapourize on impact. And the impact will create super-heated high-velocity shock waves which will travel around Mars at least once, probably...

Comet's Death Dive Into Sun Seen in Detail for 1st Time http://www.space.com/14288-sungrazing-comet-death-dive-sun-observed.html by Charles Q. Choi, SPACE.com Contributor Date: 19 January 2012 I was surprised to learn that sun-diving comets are common. I guess in the past, sun-diving comets...

I've been researching this for a while now, and none of the theory's can predict it. I've studied comets for a while now, and the tails come out of the front and then has a weird curve which goes to the back. If you guys have any random ideas or thoughts of why this is happening, that would be...

I have read a few times that comets are significant transports of ice (perhaps in having supplied water to fill Earth's oceans). That implies that water is more abundant in the few comets (in accumulated mass) that have impacted Earth than that which would have existed within the initial planet...

Hi guys, me again, with two questions. Just saw a documentation about supernova, when supernova happens, a huge amount of gamma ray is emitted since it is vacuum in space, why wouldn't the gamma ray hit us? Even if its far and takes a few thousand years for it to reach us, it would eventually...

Hi all Just a quick question What would be the maximum size to which a comet could actually go to to be able to maintain an elliptical orbit so as to follow kepler's laws To reword it what would be the least amount of eccentricity that a comet could have and what would this be dependent on?

Would you expect comets to follow the ecliptic? Explain.

I see that the current explanation for a comets tail is that as a comet approaches the sun, it starts to heat up. The ice transforms directly from a solid to a vapour, releasing the dust particles embedded inside. Sunlight and the stream of charged particles flowing from the sun – the solar wind...

This might be a good idea for a thesis. Could we alter a comet's course and make it break free of orbit and head towards another sun and populate other planets? Some of them are made up of life sustaining elements right? Could we use nuclear power to melt it to create a biosphere?

If the planets are forced into circular orbits by inertia and gravity, why are the orbits of comets oval shaped? What keeps them from entering the sun.

Some comets like Comet McNaught glow very brightly in the sky. However, they are not a sun, obviously. They are just large chunks of rock? It can't just be from the sun's reflection? Or is it as the bright ones have an ice coating around them. I know they have large kinetic energy but not enough...

As most now accept an astroid or comet ended the reign of the dinosaurs. Hollywood's idea of dealing with the threat is to fly crews to the object and blow it up. NASA's solution involves mass drivers, impact airbags of gases and dust, lasers, solar saiks and etc. **Throwing out Hollywood's...

A thread for strange connections or coincidences. I was watching Comets on THC, and it came to my attention that the Heaven's Gate cult - all of whom committed suicide - believed that the Earth was going to be recycled by the mother ship. Is is just me or does this smack of "intergalactic...

Lately, I have become quite interested in how the astronomy field has begun to determine that water can be found almost anywhere. And since it is the second most common molecule in the galaxy, at least here, I became intrigued with how it gets around so easily. This brings me to Dr Louis...

The orbital period of Comet Halley is calculated to be 75.5 years. Many other comets have orbits that extend much farther from the sun, and hence have much longer periods. At aphelion, a typical long-period comet is about 8*10^12 km from the sun; at perihelion, it passes inside the Earth's...

Something I've thought about before but never asked anybody...The existence of short-period comets is a problem if one believes the solar system is 4 billion years old, because obviously after that length of time all of the short-period comets would have disintegrated. So, we need a way of...

While some comets are only visible with the help of a telescope, this comet, seen in 1965, was visible to the naked eye even during the day! What comet was it?