15 votes

Whats the probability of a hazardous impact for human life on Mars?

We actually have a very good idea of this because the Mars Reconnaissance Orbiter has been orbiting Mars for over a decade. The MRO is, basically, a spy satellite around Mars and is continually taking ...
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  • 7,390
7 votes
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Are we less safe now that Arecibo is no more?

The linked article is copied from a university press release. Arecibo's article is more matter-of-fact but naturally also emphasizes the value of their own work. NASA Goldstone can do planetary radar ...
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  • 16.6k
7 votes
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If two stars collide, what is the probability that they merge to form a single star?

Fairly good. Two stars of mass $M$ falling from infinity straight towards each other until they merge at distance $2R$ will get kinetic energy $GM^2/R$. This is a lot, for two suns it is $1.8978\times ...
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6 votes
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Is there any known asteroid or comet whose path goes through the Earth?

JPL and ESA provide tools to search for small bodies meeting user-defined criteria. I tried: H <= 24 MOID <= 1e-4 au with each and got these results in common: (89959) 2002 NT7, an H=16.5 (~1....
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  • 16.6k
5 votes

Accuracy of predicting an asteroid strike in 1987

There are problems with this: What happens when an asteroid hits the atmosphere The asteroid will be travelling fast, more than 10 km per second. In front of it the atmosphere will be compressed and ...
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  • 91.3k
4 votes

Where can I find historic rates of meteor impact events?

The database of the meteoritical society might be what you are looking for. You can do a search by year. Based on this data, I drew this quick plot of number of recorded meteorites per year Now ...
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  • 16.8k
4 votes
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Detecting Deep Impact

Something to consider might be a large very dark (low albedo) asteroid. I would say it is quite possible a large dark asteroid (e.g. P-type) "could" be headed for us, and we would not know it until ...
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  • 3,979
3 votes

Whats the probability of a hazardous impact for human life on Mars?

Further to Mark Olson's answer, while an asteroid impact is popularly thought of as the reason for extinction events on Earth, the reality is more prosaic, with volcanism and glaciation being the most ...
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3 votes
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is there any mathematical formula, paper or anything that shows the probability of a meteor hitting a particular spot of moon's surface?

There is this source that claims 2800 kg of meteor material lands on the moon everyday. They break down that amount to determine an average area per strike. There have been other studies like this ...
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  • 4,336
3 votes

How long time since a typical asteroid collided with another asteroid?

How ancient they are, I'd have to say as old as the solar system. Collision frequency: Collision amongst Asteroid Belts From ref 1 below: Based on the particle in a box model which assumes a ...
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2 votes

How near to Earth do comets pass?

On the Near Earth Object Program web page from NASA, it lists about 80 objects that passes near the Earth over the next 4 months. Many of them pass within 0.01 AU, the closest one will pass on Oct 24 ...
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  • 1,988
2 votes

How near to Earth do comets pass?

Wired: May 19, 1910: Halley’s Comet Brushes Earth With Its Tail The 1910 pass of Earth was especially close and, thanks to expansive newspaper coverage, eagerly anticipated by the general public. ...
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2 votes

How near to Earth do comets pass?

The answer is that they don't come very close. As Wikipedia notes, It is rare for a comet to pass within 0.1 AU (15,000,000 km; 9,300,000 mi) of Earth. Even better, though, is an actual list of ...
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  • 34.1k
2 votes

What is the probability of an astronomical body hitting you?

Comets are part of the meteor calculation. Space junk is a minor concern. Most satellite and rocket bodies are fairly flimsy and are destroyed by the atmosphere. Sometimes chunks do come down. But ...
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  • 91.3k
1 vote

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

This recent paper by Napier et al. indeed concludes that centaur comets break up into many pieces large enough to cause mass extinction events on Earth. Since objects orbit in the same way regardless ...
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  • 10.9k
1 vote

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

The American Meteor Society FAQ page notes that about 95% of observed meteors are probably of cometary origin. But they're apparently so fragile that they're only about 1/3 of observed fireballs, and ...
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