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NASA predicts asteroid to make one of closest approaches to Earth ever recorded

jpl.nasa.gov

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Re: NASA predicts asteroid to make one of closest approaches to Earth ever recorded

#31

Post by generalizations »

jeffbee wrote: post #29
throwaway4aday wrote: post #26

Earlier quoted context omitted.

Imagine standing in a field on a moonless night while someone shines a flashlight at you from one direction. You are told you are surrounded by a number of people whom you can't see and that they will now proceed to throw rocks at you ranging in size from pebbles to bricks. That's roughly the level of anxiety you should have about our current situation.

Wouldn't they be throwing the rocks at the flashlight guy?

Flashlight guy is the sun blinding you so you can't see anything.

Re: NASA predicts asteroid to make one of closest approaches to Earth ever recorded

#32

Post by throwaway4aday »

JKCalhoun wrote: post #5

This is HN, I can be cynical, right? Allow me to air one of my pet peeves: articles that make the threat of an asteroid collision with Earth something we should be afraid of. (Oh, and films of course.) I never understood why anyone should give it any more than even a passing thought. As a layman my understanding is that the last great extinction event from an asteroid was like (Wikipedia tells me) 66 million years ag…

The great extinction events are just icing on the cake. We get hit by rocks quite often, one of the most recent notable ones being the one that caused the Burckle Crater in the Indian ocean. The crater is 29km in diameter and the impact happened roughly 5000 years ago. The ocean impact would have created a mega-tsunami that devastated the coastlines of Australia, India, Africa, and South Asia. God knows what the fallout from it would have looked like but it would have vaporized a lot of water and also flung masses of ejecta into the atmosphere. Land impacts can be a lot worse since the damage isn't just limited to the impact site, that ejecta again creates a large radius of splash damage. Then there are the fires, the smoke, a nice dusting of radioactive material, and don't forget the shockwave and overpressure.

We've been lucky so far but you'd have to be a fool to rely on luck forever.

Re: NASA predicts asteroid to make one of closest approaches to Earth ever recorded

#33

Post by phkahler »

Notice that this was spotted by an amateur only 2 weeks before closest approach. Why was it not found by the larger installations?

One problem I like to repeat at times like this, is that these hunts for near earth asteroids look for bright spots that move against the background stars. That's a nice way to find things nearby. But any object on a collision course with earth will not be moving against the background in the days and weeks leading up to the collision when they are also the brightest and most observable. I believe this is why the ones that have exploded in the atmosphere in recent years went completely undetected. It's not just that they're small, but that they don't have the relative motion against the sky to make them stand out.

Re: NASA predicts asteroid to make one of closest approaches to Earth ever recorded

#34

Post by throwaway4aday »

jeffbee wrote: post #29
throwaway4aday wrote: post #26

Earlier quoted context omitted.

Imagine standing in a field on a moonless night while someone shines a flashlight at you from one direction. You are told you are surrounded by a number of people whom you can't see and that they will now proceed to throw rocks at you ranging in size from pebbles to bricks. That's roughly the level of anxiety you should have about our current situation.

Wouldn't they be throwing the rocks at the flashlight guy?

No, they're stand-ins for the trajectory on closest approach to Earth. They're not trying to get the rocks to orbit flashlight guy.

Re: NASA predicts asteroid to make one of closest approaches to Earth ever recorded

#35

Post by swader999 »

LinuxBender wrote: post #8
P_I_Staker wrote: post #6

Earlier quoted context omitted.

Yeah super volcanos and solar flares on the other hand...

For what it's worth, Yellowstone's upper lava chamber is 5% molten and the lower magma chamber is about 2% molten. To get eruptions that percentage has to be much higher as it is in the Hawaiian volcanoes. Scientists have differing opinions on how many years it will take to reach that level but all of their numbers are well over 10k years. I had to look into this prior to moving near it.

What if an asteroid hits it?

Re: NASA predicts asteroid to make one of closest approaches to Earth ever recorded

#36

Post by TheCapn »

jeffbee wrote: post #29
throwaway4aday wrote: post #26

Earlier quoted context omitted.

Imagine standing in a field on a moonless night while someone shines a flashlight at you from one direction. You are told you are surrounded by a number of people whom you can't see and that they will now proceed to throw rocks at you ranging in size from pebbles to bricks. That's roughly the level of anxiety you should have about our current situation.

Wouldn't they be throwing the rocks at the flashlight guy?

Well, to make the analogy work you'd be running circles around flashlight guy while they throw at him. Maybe you're in the crossfire, maybe not.

But the other part that I think the original OP is sort of amazed at is that we're unable to detect these through some sort of automated system more accurately. It isn't fair to compare our space/vision capabilities to the eyesight of a person alone. Do we not have satellites or installations doing ""short range"" scanning with radio/laser/something-else-I-am-not-an-astronomer-don't-hate-me ? How come it was an amateur picking this up so close to the specific date?

Re: NASA predicts asteroid to make one of closest approaches to Earth ever recorded

#37

Post by shiftpgdn »

lgl wrote: post #23
guerrilla wrote: post #18

Earlier quoted context omitted.

> there are cyclical natural catastrophes That sounds very made up.

Well, we know for a fact that every once in a while, we get hit by an asteroid (which is exactly what this is about). I'd call that cyclical and not made up.

Everyone once in a while the roulette ball lands on green and I get a big payout. That's not a cyclical event.

Re: NASA predicts asteroid to make one of closest approaches to Earth ever recorded

#38

Post by LinuxBender »

swader999 wrote: post #35
LinuxBender wrote: post #8

Earlier quoted context omitted.

For what it's worth, Yellowstone's upper lava chamber is 5% molten and the lower magma chamber is about 2% molten. To get eruptions that percentage has to be much higher as it is in the Hawaiian volcanoes. Scientists have differing opinions on how many years it will take to reach that level but all of their numbers are well over 10k years. I had to look into this prior to moving near it.

What if an asteroid hits it?

Good timing on the question. We are about to pass through a chunkier part of the Taurid asteroid belt. If the rock is big enough to turn everything molten then I suppose it might be time to hitch a ride in a nuclear submarine.

Re: NASA predicts asteroid to make one of closest approaches to Earth ever recorded

#39

Post by CWuestefeld »

CWuestefeld wrote: post #9

Shameless plug: if you're interested in daily space information, including about nearby passing asteroids, give my Alexa skill "Spaceman" a try. It provides info about those asteroids, as well as any scheduled rocket launches, for any date or date range. And it throws in the moon phase as well. https://sites.google.com/view/spacemanforalexa/

I should probably add that my app isn't reporting this event. For some reason, my upstream data source[1] isn't reporting it to me. I guess it's such a new discovery that they haven't got it into their database yet.

[1] NeoWs at https://api.nasa.gov/index.html

Re: NASA predicts asteroid to make one of closest approaches to Earth ever recorded

#40

Post by JKCalhoun »

derstander wrote: post #27
guerrilla wrote: post #18

Earlier quoted context omitted.

> there are cyclical natural catastrophes That sounds very made up.

I don’t really follow astrophysics, but there were hypotheses that the motion of the solar system through the galactic plane, which has a periodicity, would induce impact events. A cursory search suggests that recent analyses of crater data may not support those hypotheses. Here’s a link to a 2011 paper suggesting as much. So the notion was certainly a reasonable one even if not ultimately true. https://academic.oup.…

Sounds a little like Nemesis [1].

The Wikipedia article mentions 26 million year intervals. So we're probably good for another 10 million?

[1] https://en.wikipedia.org/wiki/Nemesis_(hypothetical_star)

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