There's a slight chance Asteroid 2024 YR4 could hit Moon in 2032 There is a chance, albeit slim, that asteroid 2024 YR4 could hit the Moon, creating a new crater and an explosion that might just be visible from Earth. The possibility was floated by space boffins in a New Scientist article, and would leave the Moon with a crater measuring anywhere from 500 to 2,000 metres across. The Moon …
No, no, no, no, no, no, no, no, no! You start shooting stuff off of earth like that and before you know it it'll buoy itself out of sun orbit, and the milky way chocolate bar, and to where? The edge of the known and unknown universe ...
Plus, the earth's space magneto-aerodynamics and gravitational profile will be all different, with that big donut hole in the middle once all that stuff's been shot off of here and into the sun! Way too hazardous for space-highway worthiness IMHO! ;)
"To be fair the Moon looks like a terrible place for anything more than flag-planting, while the poisonous, dimly-lit deserts of Mars have more unknowns. "
The moon could be a good place for some sorts of research and manufacturing. It's relatively close proximity to Earth means that transportation each way isn't constrained to a window of a couple weeks in length every two years like Mars. Anything on Mars isn't likely to be cost effective to bring back to Earth. Having a wisp of atmosphere is hardly good compensation for lower insolation, perchlorate salts all over the place and many of the same problems that there are with the moon such as glass-like dust/fines, CSR's and solar emanations.
Even if Mars becomes a destination, setting up habitats on the moon and learning how to cope with people living there longish term will be a needed stepping stone. An "oops" epiphany with lunar inhabitants might mean them needing to return back early. For a trip to Mars, it's a write off of an entire crew.
The damage if YR4 hit earth is estimated to be around 8 megatons. (*)
That's not civilsation-ending big, and if it hit in the middle of nowhere, the effects elsewhere might not that big. OTOH, it could easily destroy most or all of a large city if it hit near enough.
(*) That's still around 500 times the size of Hiroshima, which *is* large, but not as large as that sounds, since Hiroshima was small (c 0.015 megatons) compared to almost anything from the 50s thermonuclear era onwards. The largest ever nuclear bomb ever exploded, the Tsar Bomba, was around 50 megatons, and that was able to break windows 500 miles away.
We'll have enough time to evacuate people from the area IIRC based on trajectory predictions so no real chance of it taking the current US administration out.
Plus, if there's even the remotest chance of it hitting they'll have Trump somewhere on a plane waiting it out - they don't take any chances.
"The damage if YR4 hit earth is estimated to be around 8 megatons."
Too large of a bomb in one place can be a waste. Take that same 8MT yield and have the mass explode some distance from Earth's surface and it's even worse. This is the mechanism that was used with the bombs dropped on Japan. It they just had a contact fuse, the damage would have been much less. The 50MT "Tsar" bomb turned out to be so big that it pushed atmosphere up and spent a good deal of it's total energy in the wrong direction (from a military standpoint). I don't think I've ever hear tell of where the maximum yield might lie, but I expect that sort of thing isn't going to be widely published. Of course, any government with The Bomb will be able to calculate that for themselves. It's just us peasants that shouldn't know that sort of thing.
The Tsar bomb was said to be 100MT but among the problems that presented was that nobody believed an aircraft could drop it and survive the detonation. So it was adjusted.
A megaton delivered as 10 warheads rather than one was thought to be harder to intercept, and more damaging, and was said to be a targeting mode for MIRVed missiles.
"Current estimates put the size of 2024 YR4 at roughly the same as the Tunguska impactor, so not something you want to be anywhere near if it hits but not an Extinction Level Event either."
If you define an extinction event as everybody dies, yes. That doesn't mean that there would not be tremendous numbers of deaths and a huge set back to the remaining population.
A good read is "Quantum Earth" by Dennis E. Taylor. The story begins after introduction of the characters and main storyline with Yellowstone undergoing a massive eruption. Immediately after, nation-states do their worst against each other as they already know the level of impact to the global environment that will follow. Some actions are spiteful vengeance and others are to secure resources. The sad thing is that the narrative is probably the most probable aspect of the whole story. Lucifer's Hammer by Niven and Pournelle is another good look at what might be expected from a large scale catastrophe. Global society is a precariously balanced thing. Too big a push in some direction might topple a great many things.
The prediction is that the asteroid will cross the earth's orbit at a quite accurately known time, but a less accurately known location. So there is some geometric figure which is at risk, which includes the cross-sections* of the earth and the moon.
As the accuracy improves, the figure gets smaller.
But the Earth doesn't.
So the probability that the asteroid passes through the part of that figure occupied at that moment by the Earth ... increases.
At some time the figure contracts to not include the Earth, and the risk declines to zeroish, or alternatively the figure contracts to not include anything but the Earth, and the risk rises sharply to unity. Binary, what.
Whether we can refine it to 0||1 before it provides the worked example I do not know. Probably someone does.
* Solid, plus atmosphere, plus gravitational effects.
Ejecta will go elsewhere on the moon.
Escape velocity is a shade under 2.5km/s - that's probably more than the vast majority of the ejecta.
Then have to get that ejecta to escape in the direction of earth, rather than any other direction... (though escape velocity in that direction will effectively lower...
Though maybe a little more than I'd expected:
https://www.sciencedirect.com/science/article/pii/S0019103585711931
Given the likely size of ejecta, and how far out the moon's gravitational force trumps the gravitational force of the earth, I think that ejecta would likely be pulled back to the moon's surface by lunar gravity.
In the event that any debris be ejected towards the earth, far enough for earthly gravity to take over, I'd like to think that it would burn up in the earth's atmosphere.
> I'd like to think that it (debris from hitting the Moon) would burn up in the earth's atmosphere
Yes. But to get to Earth's atmosphere it has to pass through all the usual orbits inhabited by satellites. Whether geostationary or LEO.
And we know how worried satellite owners get about the effect of hyper velocity tiny specks hitting their hardware.
Although we don't know much about this asteroid, a low estimate of its size is 50m diameter. That gives it a volume of 65,000 m³ impacting the Moon at 17km/s.
That can throw up a lot of dust.
See https://www.scientificamerican.com/article/in-a-first-earthlings-spot-a-meteor-strike-the-eclipse-darkened-moon/ for an image of the eclipsed Moon being hit by a meteorite.
Lumps of rock hit the Moon quite often, as it has a minimal atmosphere. Small pieces of rock burn up in the Earth's atmosphere.
>>that was a HOAX!!!
you mean Tintin and Capt. Haddock aren't real?
It's all made up? a Fiction?
Say it isn't so... my whole world view has just been smashed... I will have to go off and put tariffs on Belgian goods enetering this sceptered isle... no... wait... that means less beer...
nurse- dried frog pills! STAT!
Is "circularize" really a word?
Of an ex colonial origin I guess. Never mind, we let it (the colony) go.
Butchering words is about the best industry they have since the poor "septics" have neither their own natural resources c.f. Greenland, Ukraine, nor any decent beaches c.f. Gaza, can't invent anything useful: see Tim Berners Lee (WWW) or Alexander Graham Bell who only became an American in later life
https://www.songtell.com/richard-thompson/alexander-graham-bell
"Is "circularize" really a word?"
In astrodynamics, very much yes it's a word. It literally means to turn an elliptical orbit into a circular one. Whether it's spelt with z or s is a discussion I'm going to quietly back away from.
(Strictly, all orbits are elliptical, but some are close enough to a circle to call them circular)
The probability of 2024 YR4 hitting the Earth is larger than for the Moon. Wikipedia lists (and links to the source), that the current probability of 2024 YR4 hitting the Earth is 2.6 %, i.e. 1:38. The ESA lists as of now the probability as 2.41 % (1:41). IF the asteroid hits the Earth and the shown possible impact line holds, it could destroy the ESA space centre in Kourou, French Guiana, or it could go to central Africa or India or the Atlantic or Indian Oceans.
If it hits the Earth, it's going to to be somewhere close to the equator (map here) So Russia, the US, Europe*, Australia etc. can all breath easy. The north of South America, most of Central Africa, Yemen, India and possibly China all need to be slightly worried.
* French Guyana is under the track, which is technically part of Europe.
@Omnipresent
There are literally millions of Russians who object to Vladimir Putin's regime. Putin has imprisoned thousands of his opponents, has almost certainly ordered the murder of Alexai Navalny, and Alexander Litvinenko and the attempted murders of the Skripals in England. Whatever animosity you may have to the current Russian regime, please do not take it out on the Russian people.
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