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Well, the internet lies a lot, so there's so much information mixed with misinformation...

Some sources call what killed the dinosaurs an asteroid and others a meteor.

Is there any consensus on this?

By definition, an asteroid would never collide with Earth, because the moment it entered the atmosphere it would be called a meteor, or am I wrong? Or else, by the size of the celestial body and/or the speed with which it entered the atmosphere and/or the little impact that the atmosphere had in this collision, does it say that it was an asteroid that collided with the Earth, with no mention to meteor/meteorite therms?

Also, was it really an asteroid that started to enter the collision route with Earth, and not a meteoroid from a bigger celestial body?

Finally, if that body was so great that collided with ground, why is it not called meteorite?

Or is the total confusion in internet because there is no consensus in science community about that past event, and there are only a lot of hypothesis and a few evidences and theory?

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    $\begingroup$ are you looking for truth on the internet, even though "the internet lies a lot"? this question might be better asked on English Language Learners or a dictionary: meteor, asteroid, meteorite. have you looked at dictionary definitions of the words you use? $\endgroup$
    – Aaron F
    Jun 12, 2023 at 17:01
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    $\begingroup$ @AaronF: dictionaries and language-learner resources (including ELL SE), are generally based on some mixture of colloquial and technical usage, which sometimes agree but not always. OP’s question concerns technical definitions and precise facts, so it’s better at home on a scientific site. $\endgroup$ Jun 13, 2023 at 11:54
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    $\begingroup$ @AaronF - suggesting a dictionary for technical definitions is worse than useless. $\endgroup$
    – Davor
    Jun 13, 2023 at 12:10
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    $\begingroup$ An enormous rock. $\endgroup$
    – Mark
    Jun 14, 2023 at 2:29
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    $\begingroup$ Could we first have your own thoughts on what constitutes an asteroid and what a meteor, and why neither clearly fits better here? Either way, what difference d'you hope to make of it? $\endgroup$ Jun 28, 2023 at 16:54

4 Answers 4

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Definitions:

  • A meteoroid is a celestial object larger than an grain of dust and smaller than 1 meter in diameter.
  • An asteroid is a celestial object larger than 1 meter in diameter.
  • A meteor is a streak of light caused by superheated air as a meteoroid enters the atmosphere.

A meteor is NOT the space rock which causes the meteor: it is not any type of solid object. So the impactor which killed the dinosaurs was an asteroid which might possibly have made a meteor appear in the sky before exploding with the force of millions of atomic bombs.

A meteoroid (/ˈmiːtiərɔɪd/) is a small rocky or metallic body in outer space. Meteoroids are distinguished as objects significantly smaller than asteroids, ranging in size from grains to objects up to a meter wide. Objects smaller than meteoroids are classified as micrometeoroids or space dust. Most are fragments from comets or asteroids, whereas others are collision impact debris ejected from bodies such as the Moon or Mars.

A meteor or shooting star is the visible passage of a meteoroid, comet, or asteroid entering Earth's atmosphere. At a speed typically in excess of 20 km/s (72,000 km/h; 45,000 mph), aerodynamic heating of that object produces a streak of light, both from the glowing object and the trail of glowing particles that it leaves in its wake. Meteors typically become visible when they are about 100 km (62 mi) above sea level. A series of many meteors appearing seconds or minutes apart and appearing to originate from the same fixed point in the sky is called a meteor shower.

An estimated 25 million meteoroids, micrometeoroids and other space debris enter Earth's atmosphere each day, which results in an estimated 15,000 tonnes of that material entering the atmosphere each year. A meteorite is the remains of a meteoroid that has survived the ablation of its surface material during its passage through the atmosphere as a meteor and has impacted the ground.

In April 2017, the IAU adopted an official revision of its definition, limiting size to between 30 μm (0.0012 in) and one meter in diameter, but allowing for a deviation for any object causing a meteor.

Objects smaller than meteoroids are classified as micrometeoroids and interplanetary dust. The Minor Planet Center does not use the term "meteoroid".

(Wikipedia)

The object which killed the dinosaurs was several kilometers or miles in diameter, and so was not a meteoroid. It was totally vaporized upon impact and so left no meteorites on Earth. It was not a meteor but may have made an meteor as it passed though the atmosphere.

So the question is whether the object which killed the dinosaurs was an asteroid or a comet, and at the present time it is thought to have probably been an asteroid rather than a comet.

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    $\begingroup$ Of course, this can easily become "typology" and not astronomy. However, the sentence An asteroid is a celestial object larger than 1 meter in diameter should likely not be taken as the full definition of the term asteroid since it does not exclude comets, planets, stars etc. Of course, I am not claiming you meant that sentence to be a full definition; you meant only to draw a line between meteoroid and asteroid. $\endgroup$ Jun 12, 2023 at 11:18
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    $\begingroup$ Wait, it was totally vaporized upon impact but only may have made a meteor? $\endgroup$ Jun 13, 2023 at 13:18
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    $\begingroup$ Good answer - it could be slightly improved by saying explicitly that a meteorite is a rock found on Earth that used to be part of a celestial body. (The answer implies that but doesn't quite say it.) $\endgroup$
    – N. Virgo
    Jun 14, 2023 at 11:02
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    $\begingroup$ Can you provide some references other than the wikipedia page? Specifically it seems like many definitions of 'meteor' do not agree with you. I have always heard that 'meteor' was simply a meteoroid that had entered the Earth's atmosphere, not just the trail. Even this page on Nasa is contradictory. It later says meteor is the trail, but starts off with "Shooting stars" or meteors are bits of material falling through Earth's atmosphere" $\endgroup$ Jun 14, 2023 at 13:45
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    $\begingroup$ Also: this. Though the Oxford agrees with you. However that seems extremely clumsy to me. "What do you think caused that meteor?" "You must know it was a meteoroid already, otherwise you that streak of light isn't a meteor." Also 'oid' as a suffix means 'like'. Certainly space rocks are nothing like streaks of light in an atmosphere. $\endgroup$ Jun 14, 2023 at 13:59
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Based on the Wikipedia article:

There is broad consensus that the Chicxulub impactor was an asteroid with a carbonaceous chondrite composition, rather than a comet.

And it cited a paper which explains the query: Steve Desch et.al., The Chicxulub impactor: comet or asteroid?, Astronomy & Geophysics, Volume 62, Issue 3, June 2021, Pages 3.34–3.37, DOI: 10.1093/astrogeo/atab069

By definition, an asteroid would never collide with Earth.

Wrong. Asteroid can technically collide with Earth and when it does, it will be called Impact event. However, the chances are extremely rare given how vast is space. Check out: https://starchild.gsfc.nasa.gov/docs/StarChild/questions/question11.html

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  • $\begingroup$ I said so because that logic: when it enters atmosphere, it is no more called "asteroid/meteoroid", but "meteor/meteorite", so collisions are with "meteors/meteorite", not with "asteroids/meteoroid". But this question is just to answer if it is right to say it ;) $\endgroup$
    – kokbira
    Jun 11, 2023 at 11:57
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    $\begingroup$ There's also the issue with entering the gravity well. Descending a celestial body's gravity well is very hard for objects without self-propulsion. That's why black holes have disks. Most matter and light are caught by the gravity field and sent spinning instead of colliding with the celestial body. $\endgroup$ Jun 13, 2023 at 13:20
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    $\begingroup$ @Mindwin Remember Monica: Entering a planets Hill sphere, which is presumably what you mean with "entering the gravity well", is very different from entering the planets thermosphere, which is when Mach number and gas density start becoming so high that the object burns up. Black holes have disks because of angular momentum conservation, so have protostars. $\endgroup$ Jun 13, 2023 at 17:57
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Your question asks "Which kind of celestial body"

Meteorites and Meteors are not celestial bodies. Meteorites are not celestial, they are a type of stone that is sometimes found on Earth. Meteors are an atmospheric effect, and not a "body" at all.

There's no firm distinction between "meteoroid" and "asteroid" except "meteoroids" are small. The object that struck Earth was large. Hence it was probably an asteroid (though it may have been a comet)

It was an asteroid right up to the moment it hit Earth. And after that, it wasn't anything at all, since it was completely destroyed.

This is just how English (the language) works. We say "I broke the window", even though after breaking it, it isn't a window any more; it's just some broken glass on the ground. We say the balloon burst, even though it isn't a balloon after it has burst. We might say "The Prime Minister resigned", but after resigning, they aren't Prime Minister. And we say "An asteroid hit the Earth" even though after hitting the Earth, it isn't an asteroid any more.

Not science, just English.

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  • $\begingroup$ You just earned the philosopher's stone badge... or philosopher's meteoroid badge :) After learning that "meteor" is not a celestial body, but the luminous phenomenon of an asteroid or meteoroid entering the atmosphere, I understood that the entry of the atmosphere does not change the nomenclature of the celestial body. Who impacts the ground is the asteroid or meteoroid (this one if it succeeds). The explanation about the abstraction of referring to a destroyed object in language is part of the meta-understanding. $\endgroup$
    – kokbira
    Jun 15, 2023 at 14:21
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Both are correct.

Yet talking of a meteoroid (or meteorite once on earth) is not very helpful in this context as that does not say anything about the object other than 'falling from space onto Earth'. That is obvious here.

Talking about an asteroid which collides with Earth conveys a lot more information, as it indicates certain properties (size range, age, somewhat chemistry,...) and also somewhat origin (I. e. not a comet).

For the reasons outlined above, in science one most likely will talk about small asteroids in this context. Or you discuss the impactor being either an asteroid or comet...

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    $\begingroup$ My kid is preparing a science presentation about asteroids but a lot of questions appeared, and it is one of them :) So we found in internet about "Chicxulub impact", but some articles saw the celestial body was an asteroid, other saw it was a meteor (other saw it was a comet). Also by definition of meteoroid and meteorite, these terms appeared on this question on SE... $\endgroup$
    – kokbira
    Jun 11, 2023 at 12:14
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    $\begingroup$ @chux-ReinstateMonica I really don't know. I have to leave that judgement on details of English grammar to native speakers. Please edit for clarity of language :) $\endgroup$ Jun 12, 2023 at 22:49

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