Odds wise, we’re in roulette or 5 heads-in-a-row coin flip territory. It also seems like they pretty closely know the timing and thus what face of Earth will be facing its approach. And it’s currently moving away and will be out of telescopic range by April, Need more data, taylor swiftly!
So putting this in persective with the previous observation, 3 weeks ago we had six coins that all needed to come up heads in order for the asteroid to hit us, and the most recent estimate just told us that the first coin came up heads.
It would be nice if it were tails, but not overly unlucky that is wasn’t.
This block of asteroid isn’t big enough to cause a tremendous amount of damage - maybe a local tsunami or some interesting looking sunsets if it hits land with what it blows into the atmosphere. It didn’t matter with the dinosaurs - that asteroid impact made it Winter All Over for a Long Time.
I’m believe that’s the wrong way to look at it. Those dots are the result of a Monte Carlo simulation. I think at this point, the actual probability distribution is even, along the entire line. No spot along it is likelier than any other. The full line currently extends many times the diameter of the Earth out in both directions. Probably one direction is shorter than the other. They might be able to assign higher probabilities to different places at some point, but that will happen only after the chance of hitting Earth becomes a definite 100%. Based on what I learned when I asked a similar question a while ago, we might never get that level of certainty before it either hits or passes on by.
If it’s very likely to not miss, we’ll ballistically hit it and Newtonian mechanics will do the job. The Moon has been our ungrateful protectorate against space debris so maybe it will take the hit which will be really cool and no space missions even necessary. A good thing as the Moon and its gravity and impact tolerance remains free unlike any space missions cost money and cooperation which we do not have now and I would venture we’ll have less of in six or so years. So either we figure out it’ll be a near-hit (i.e. a miss) or the Moon will take the hit, or if Earth has to (and it will not) it could send some big-ass bullet to knock this thing off course.
Other than tsunamis, what would happen if it hit the ocean? Everyone keeps talking about a hit on land but I assume a water landing would also have…interesting…consequences.
There are a lot of factors.
- First — as I understand it, current assumptions are that this is a conventional “stony” asteroid. Those tend to explode in the atmosphere, rather than making it all the way to the ground. Think Tunguska, which basically had the effect of a small nuke detonated at altitude.
- If that assumption holds true, then such an airburst above the middle of the ocean would have no immediate destructive impact. However, see following points.
- If the assumption is wrong and the asteroid is made of stronger stuff, then it could actually impact the water. Out in the deep ocean, there wouldn’t be much tsunami risk on distant coastlines, for example.
- Either way, though, some amount of water will be vaporized. Airburst = less, impact = more. A sudden injection of water vapor into the atmosphere is likely to create climate effects; at the upper level, our greenhouse warming already in progress will be somewhat accelerated. Probably not a massive effect at this object’s size, but really, we can’t afford any unwanted increases right now.
- Also, it’s not enough to simply speculate on an ocean impact — where in the ocean the asteroid lands is significant. Per above, somewhere out in the middle of the Pacific will be spectacular, but create limited damage (give or take an unlucky island or two). However, a coastline landing — say, in the ocean a few kilometers west of San Francisco — will mean the Bay Area is about to have a very bad day.
- But, again, there’s a distinction between an atmospheric explosion above water and an actual impact in water, so the effect, as above, will vary.
So … when you ask about a water landing, you’re really asking about seven or eight very different scenarios with pretty dynamic modeling, compared to the somewhat simpler projections involved in energy release on or above ground.
This is just my lay understanding based on lots of reading over the years, so if a genuine expert wants to take an axe to my bullet points, feel free. 
An unlucky 90 ° hit into the center of the Atlantic might explode with 15-40 megatons, so somewhere between a Tunguska and a Tsar-Bomba. It certainly would vaporize on impact - if it made actual impact. That would cause 50-100 meter waves for about 100 miles around so would capsize and sink just about any vessel. Then the tsunami would go on to flood NYC, Miami, Rio, parts of Europe and unfortunately, lots of the Caribbean.
A lesser angle would cause less of a wave and less of the original mega-tsunami and cause only minor coastal flooding. Either way a good deal of water vapor will make things a bit cloudy regionally. So say a 45 ° hit like Chelyabinsk and an asteroid that explodes before hitting the water would be interesting to see but not be as devastating.
I’ve got to think if this one is plotted to come any closer than the long known (relatively) asteroid that passed within 3 earth radii 16 hours after Chelyabinsk it will have to be nudged away. That asteroid could have hit Geostationary satellites and I’m unsure if the course was so well known that some (satellite owners) weren’t holding their breath.
Since this one has been known about for a month or so, and will be out of telescopic range in two more months, if astrophysicists cannot get a better idea before then, we may be fortunate enough in 2032 to catch up with it on approach to the sun so in either case less than a year lead-time and it would behove us (whomever that collectively is) to have something ready to go. Might be a good thing to have that ASAP.
That’s @Cervaise and @Coriolanus. This is why I love this place.
Very good overview article, accessible to the lay reader, with all your answers (insofar as they can currently be answerable).
I’m struck by three things from that article.
- NASA/America is in the vanguard of space defence
- The projected impacts are nowhere near America
- The next and best window for any kind of deflection mission is 2028
Given who will likely be in charge of the US and the US’s space programmes at this point, the already significant barriers to international co-operation just got higher, and the barriers to “America not shaking down the developing world like a cheap gangster” just got a lot lower.
I’m struck by how there’s a distinct non-zero possibility that “Don’t Look Up” might turn out to have been a documentary. Sure, Trump won’t be president (or king) in 2032 (I hope) but if one of his successors is, I bet we’ll hear “The asteroid will bring jobs! Fake news that it will kill us!” for months before it hits.
Well, I, for one, would not object to the America-hating fuckstick having an intimate encounter with a Bronteroc.
Perhaps it would like a nice Musk melon for dessert.
It looks like Musk’s plan to de-orbit the ISS has saved us! The chance of this asteroid hitting the Earth has dropped to 0.28%.
I recall from the original articles that is was 60-90 meters wide and don’t recall it being oblong or roughly round. This was when it was a 1.9% chance and they said it typically approaches zero.
I’ll leave it to experts yet without size updates and obviously if it’s 90° or much less matters and I’d not write off a direct ocean hit as “nothing will happen” as much as it’ll hit the Australian Outback. Never say “never never” (sorry couldn’t resist).
“Don’t look up” and such were rocks many kilometers across or as much as the plot needed. The Chicxulub Dinosaur Killer that allowed us primates to be here was 10K/6 miles wide yet it’s thought that Jupiter and the other giant planets helped “sweep” the inner solar system of those things in the last 66 million years (although likely tugging it in to begin with).
There’s no “money” in setting up something to nudge an asteroid (Musk would prefer to mine it for minerals) yet it’s quite possible this one - or any number of others - could have been missed entirely till somewhere in 2031 and all the Teslas iin Space and planting flags on Mars (and renaming it?) will look even stupider than they do now.
The European Space Agency did the last nudge-the-asteroid mission just as a proof of concept. And then there’s the Russians and China and maybe India who could at least cooperate sans NASA if this thing looks like it’ll hit. Of course once (as is likely) it’s zeroed out we can go back to ignoring the threat. Just like in those movies, if a really big one is coming there’s nothing we can really do anyways.
On an unrelated note, I had not heard Musk has the call on the ISS and I reckon that being a science mission where we still had cooperation (and not capitulation) with Russia was a good thing. I’ve not heard the term “de-orbit” before.
To be clear, the ISS was already planned to be deorbited in 2031, and SpaceX already had the contract to build the vehicle to do so. Musk’s recent suggestion (and it’s just a suggestion) was just to do it a few years earlier.
The political situation is definitely a bit complicated with the Russians involved. Though it’s theoretically possible to disconnect the US portion from the Russian one (as long as you don’t need the ISS to be functional afterward).
I think you may be overestimating the complexity of the mission. It’s just launching as large a mass as practicable into the path of the asteroid when it swings by near its perihelion in 2028, thus slowing it down, resulting in it arriving slightly sooner in 2032 so that the earth hasn’t quite arrived to intersect its path. Yes, I know slowing something down so that it will arrive at its destination sooner is weird, but that’s orbital mechanics for you. The only tricky thing about it is a terminal guidance system so that it can successfully maneuver itself into the path of the asteroid at extremely high closing speeds, but that guidance technology is exactly what DART demonstrated.
Should there be the political will to fund development of the mission, I think it would be possible (assuming the math works out re: required mass to adequately alter the asteroid’s orbit vs extant heavy lift capacity), but I also expect that said funding will not be forthcoming. In 2028 we’ll get highly accurate orbital period data, and so we should at that point know pretty precisely if and where we’ll get hit, and if the worst case pans out I’m guessing large-scale evacuation is probably more likely than large-scale DART.
Just guessing, but I suspect evacuating Lagos would cost more than the supersized DART.
Plus the difficulty about getting all the money from the princes out of the country.
“Good news everybody!”
Asteroid 2024 YR4’s odds of hitting Earth just got a lot smaller
Might be wise to wait till Sky & Telescope concurs, or some famous Astrophysicist or Elon Musk the Wise does. Now we can get back to all the concern about the 2038 Unix Epoch Problem and how some Operating System that’s 55 years old will eventually end the world as we know it.
Apologies for the flippant remark about Unix 2038 problem. Totally unrelated to this asteroid and I’ll find an appropriate thread and just leave off by saying that in some areas, like aviation, things look better than a year or two ago.