Questions tagged [asteroids]

Questions regarding relatively small rocky bodies in an orbit around the Sun.

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75
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2answers
14k views

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 ...
27
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5answers
5k views

How early could we detect an asteroid the size of the one that caused the extinction of the dinosaurs?

Would we know months, years ahead? How sophisticated is our technology's ability to detect it at 100% accuracy?
22
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1answer
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What would an asteroid inside of Mercury's orbit be called?

The first Vatira asteroid has been discovered. This makes me wonder if there is already a name for the hypothetical class of asteroids that orbit entirely inside of Mercury's orbit. It wouldn't be the ...
20
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3answers
4k views

Does anything orbit the Sun faster than Mercury?

Mercury's orbital period around the Sun is about 88 days. Comets and other things have gotten closer to the Sun than Mercury does. But has there ever been an asteroid or some other body discovered ...
20
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3answers
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Why did the distribution of asteroids discovered in 2010 have a radial modulation?

This answer links to one of Scott Manley's excellent asteroid videos Asteroid Discovery - 1970-2015 - 8K resolution. The animation highlights the positions of the meteors at the moment of their ...
19
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2answers
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Whats the probability of a hazardous impact for human life on Mars?

Yesterday my sister and I have discussed the recent efforts of SpaceX to create a permanent colony on mars. When coming to the several dangers of creating a habitat on a different planet, we got ...
18
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1answer
420 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?
18
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3answers
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Why are asteroids with zero orbital inclination rare?

This is a plot of orbital inclination ($i_p$) vs. semi-major axis ($a_p$) of 96944 asteroids in the Main Belt, done by Piotr Deuar. Some structure can be seen in this diagram; clumps are asteroidal ...
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3answers
4k 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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2answers
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Why haven't Earth and Venus got any tiny moons? Or have they?

Why haven't some meteoroids gotten caught in Earth's or Venus' orbit? AFAIK most meteors are tiny fragments from comets. Shouldn't some comet tail sometime have passed Earth orbit at velocities ...
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3answers
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Has anyone back-calculated previous close encounters between the Apophis asteroid and Earth?

The Apophis asteroid was only discovered in 2004, and shares an orbit similar to Earth's orbit, leading to many close encounters on the scale of decades. Most of the stories about this asteroid are ...
16
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1answer
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What are Trojan Asteroids and where are they located?

Asides from the main Asteroid Belt, there are Trojan Asteroids - what are these and where are they located?
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What caused this mysterious stellar occultation on July 10, 2017 from something ~100 km away from 486958 Arrokoth?

In 2017 a series of stellar occultations by asteroid 2014 MU69 "Ultima Thule" now officially named 486958 Arrokoth were timed in order to obtain better orbital information before the New ...
15
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1answer
288 views

Is the Apophis asteroid a concern for planet Earth?

I was watching the TED lecture How to defend Earth from asteroids , and the speaker Phil Plait spoke of the possibility of this asteroid hitting Earth. Is this really a concern?
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2answers
560 views

What is the difference between the Yarkovsky effect and YORP effect?

As far as I understand, both the Yarkovsky effect and the Yarkovsky–O'Keefe–Radzievskii–Paddack (YORP) effect exert forces upon bodies as a result of thermal photon radiation. How do both effects ...
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4answers
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Do comets contain any significant amounts of iridium?

I have Googled "iridium content of comets" and can't find anything that suggests comets contain iridium in any detectable quantities. Yet, whenever I read an article about the Chicxulub impactor, the ...
12
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1answer
273 views

Why was this asteroid (4864 Nimoy) chosen to be named after Leonard Nimoy?

The asteroid 4864 Nimoy was recently named after Leonard Nimoy. It was discovered on September 2, 1988 so it went nearly 27 years without a name. Why was this asteroid chosen to be named after him? ...
12
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2answers
898 views

How can astronomers determine the difference between “hydrostatic equilibrium” and “just happens to be spherical”?

This is relevant for the definition of a dwarf planet. I presume the answer will be, well, if we can tell the mass of the body and guess the material. I don't find this very satisfactory because (1)...
11
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1answer
769 views

Opportunities to see a near earth object via unaided eyes or binoculars?

I would like to see a near earth object proper with my eyes or binoculars someday. Has this been possible recently? Are there any upcoming potential opportunities to do so in say the next 20 or 50 ...
11
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1answer
1k views

Could this estimate of the size and mass of the Chicxulub Impactor be accurate?

My understanding has always been that the Chicxulub Impactor was in all likelihood an asteroid with a diameter of about 8 - 12 km, but then, the other day, I came across this paper. In it, they say ...
11
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2answers
683 views

How was Earth's “quasi-satellite” 2016 HO3 “first spotted” and it's orbit determined?

Under a question I asked a few days ago Have there been any documented mini-moons since 2006 RH120? @Hobbes mentioned the recent news about 2016 HO3 - a near-Earth asteroid that stays near Earth ...
11
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1answer
661 views

What is the composition of an asteroid in percentages?

I am developing a RPG game (or so I like to tell myself) within outer space. Within the game, players would be able to mine small asteroids and collect resources, in order to make money. I'm having ...
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4answers
690 views

Why do planets tend to rotate in the same direction although they have formed from tumbling asteroids?

The axial tilts of asteroids seem to vary randomly (let me know if this premise is wrong), while the planets have a strong tendency to rotate in the same way. If planets were formed by colliding ...
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3answers
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How well would the Moon protect the Earth from an Asteroid?

Would the Earth fare better if the Moon blocked the meteor, comet, rogue planet, or otherwise rather than a direct impact? At what point would the Moon's debris would be an extinction event? The ...
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3answers
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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?.
10
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1answer
465 views

Could asteroid 'Oumuamua actually be round?

News articles have mentioned that the recently discovered asteroid 'Oumuamua is theorized to be greatly elongated based on observations of brightness variation. However, this hypothesis seems to be ...
10
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1answer
265 views

Detecting Deep Impact

There have been several accounts in media articles of asteroid near misses, many describe that the asteroid was not seen before the near miss. After reading the question and answer to How can we tell ...
10
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1answer
181 views

Why haven't more captured small moons been found?

Shouldn't captured moons have the same size distribution as asteroids? And asteroids are more common the smaller size they are. Moons are likely captured if they are in highly inclined orbits, and ...
10
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1answer
354 views

Is this object an asteroid or comet, and how can it produce so many tails?

The NASA Hubble Space Telescope Science Release HEIC 1320 - When is a Comet not a Comet? - Hubble astronomers observe bizarre six-tailed asteroid is self-explanatory, but it doesn't explain what ...
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3answers
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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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2answers
2k views

Gravitational Properties of Asteroids

How large would an asteroid have to be in order to hold a person so that the person could not escape?
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4answers
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Do asteroids have a gravitational field?

I know that asteroids are huge chunks of rock, orbiting a solar system. Do asteroids have a gravitational field and do they gravitationally attract each other to form planets?
9
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1answer
533 views

Asteroids between Mars and Jupiter

Is the cluster of asteroids between Mars and Jupiter two dimensional as seen in every model of solar system shown in books or television? Or is it three dimensional as i think it should be?
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2answers
508 views

Do NEA (Near Earth Asteroids) have minable water ice?

Water is very useful for rocket fuel and life support in space. But does water, in abundance and form which conceivably could be usefully mined this century, really exist in NEA's? Or do we have to go ...
9
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2answers
2k views

Why don't planets and asteroids have (cometary) tails?

Comets have tails. We all know that, and a lucky few have seen the better known. So why don't the planets (e.g. Earth, Mars) have tails? Why don't asteroids don't have tails?
9
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1answer
574 views

How is the total mass of all the Solar System's small asteroids and meteoroids estimated?

This diagram from wikipedia (shown below) graphs asteroid Diameter against Number of asteroids, for the Solar System. (Graphic is courtesy of the Marco Colombo, DensityDesign Research Lab). ...
9
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1answer
199 views

Period coincidence of Planet Nine with furthest Kuiper belt objects

A lead scientist of the Planet Nine theory said that "The period with which it goes around the sun is a rational multiple of the periods of all the furthest Kuiper Belt objects" To what degree of ...
8
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2answers
622 views

Orbits of Trojan Asteroids

I understand that the Trojan points are located 60 degrees ahead and behind a planet in its orbit. However, since there are quite a number of Trojans in Jupiter's orbit, they cannot all be exactly at ...
8
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2answers
445 views

Do astronomers generally agree that the distinction between comets and asteroids is not so clear?

edit: I just saw this tweet and find it incredibly relevant :) begin question: See this answer and then consider if there are known or likely solar system bodies that might be identified as both ...
8
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1answer
5k views

Does Jupiter help to protect the Earth against comets/asteroids impacts?

Does Jupiter help to protect the Earth against comets or asteroids impacts? Some astronomers believe that one reason Earth is habitable is that the gravity of Jupiter does help protect us from some ...
8
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1answer
453 views

Are we less safe now that Arecibo is no more?

update 3: uhoh! Source: Reddit update 2: Sadly, parts of the dish have collapsed, several cables have snapped, and the Arecibo radio telescope is now decommissioned and demolition has been ...
8
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2answers
2k views

If an Asteroid was to strike the Earth, would it affect the Earth's rotation?

If an Asteroid was to strike the Earth, would it affect noticeably the Earth's rotation, and if so, how large would this Asteroid have to be?
8
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1answer
833 views

What are the most valuable meteorites and asteroids in terms of precious metals?

There were some suggestions that asteroids could one day be mined for precious metals. I have found an outdated study that says that some siderites contain as much as 0.001% of gold: http://pubs.usgs....
7
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1answer
172 views

Are there any natural satellites in retrograde Sun orbit?

As I watch the video of the asteroids being discovered, all I see is prograde orbits. Their prevalence is fully understandable and justified, but the Sun gets interstellar visitors occasionally and I ...
7
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1answer
274 views

How loud was the asteroid that killed the dinosaurs?

Asteroid impacts on the Earth can be very loud when they break up in the atmosphere, like Chelyabinsk, captured in this video: The Chelyabinsk asteroid break-up was ...
7
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1answer
503 views

How can we tell if the asteroid 2013 TV135 will hit Earth in 2032?

Some astronomers in Ukraine have estimated that there is a small likelihood (1 in 63,000) that the asteroid 2013 TV135 will strike Earth in 2032. (source) Don Yeoman of NASA JPL says: with more ...
7
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2answers
179 views

Can the Gaia telescope detect small temporarily captured asteroids near its Lagrange orbit?

The Gaia space telescope is in a Lissajous orbit around the Sun-Earth Lagrange point 2. The orbit period is about 180 days and the size of the orbit is 263,000 x 707,000 x 370,000 km. It has been ...
7
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1answer
223 views

Is 486958 Arrokoth (2014 MU69 aka Ultima Thule) the only solar-system object determined to be binary by occultation?

The asteroid 486958 Arrokoth was discovered to be binary by astronomers lugging a bunch of telescopes around (I think) camping with them. The timing offered additional astrometry for the orbit ...
7
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1answer
68 views

Where can I find historic rates of meteor impact events?

I have a friend that watches a lot of TV news and they have the impression that impact events are becoming more common than in recent memory. Does the evidence support or refute this? Thinking it ...
7
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1answer
2k views

What would happen if asteroid 99942 Apophis collides with the earth?

In the news recently it's been said that in 2029 the asteroid called Apophis, aka 'The God of Chaos', will fly by very close to earth. To quote Geek.com In 2029, a massive asteroid called 99942 ...

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