
Not a good sign...
"Please stand by...
We're experiencing technical difficulties"
Hopefully the technical difficulty is not someone has got their measurements wrong!
It's the plot of a dozen movies and Sci-Fi books: an asteroid large enough to do serious damage to Earth is spotted just a few days before it sails close to our stellar doorstep. Faced with the possibility of extinction humanity does the only sensible thing: stream it live on the 'net. That's what the Slooh Space Camera did …
"The rock's passing 11 Lunar Distances from Earth, which is to say it'll be 11 times more distant from Earth than the moon."
So basically it doesn't even come within the moons orbit around us. Yet we've also had meteorites which actually came within this virtual boundary, so how does that make this particular object "unsettlingly close"?
"Discovered just last week, NE19 is said to be the size of a football field"
Or the equivalent to one hundred metersticks laid end-to-end or approximately the width of the white house (where the President of America lives) or the length of a typical US city block or as tall as Godzilla ..
"Discovered just last week, NE19 is said to be the size of a football field"
Yeah, this is really starting to annoy me. When they mention a new asteroid discovered in a safe orbit, you always get a full description, ie: "The asteroid now known as 'Burbank' is a potato-shaped asteroid 380 meters in length, and 120 meters at its widest width."
Whereas, the 'Earth threatening' ones only get partial measurements like these:
linear - '54 meters long', What? Snakes are long, sticks are long, poles are long. Are aliens are chucking big spears at us? Or worse:
'54 meters across' Across implies a width that's small compared to its length, llike 'the road is forty meters across', or 'To fit through the isthmus canal, a ship can be no more than 50 meters across." Jumping javelins! The aliens are chucking Mahoosive spears at us!
Then we gret the ones like in this article:
2 dimensional - 'The size of a football field', or 'the size of Manhattan', or 'as big as a 40 hectare field' Gives the impression that Galactus sized aliens are flicking playing cards at us, no real harm, unless one that hits doesn't stick deep enough and falls over on something important.
But seriously, can't they just give the size in estimated tonnage? It might be inaccurate, but it''d give a better mental picture of what's whizzing around out there.
Less Lucifer's Hammer, more Lucifer's Steak Mallet. It'd make a big, nasty hole somewhere, but we'd get over it.
Ask yourself the following question to understand how serious this would be. If it had hit Australia, would it have displaced the Royal Baby (tm) from today's headlines? What if it had hit, say, Venezuela?
(My answers are "possibly in the broadsheets" and "no").
Even if it had been a true apocalyptic event, the headline would have been "Royal Baby unlikely to survive apocalypse - Public's reaction pages 2 to 32".
On a different note, why are we measuring a three-dimensional object by its length? Is it a perfect sphere of diameter 100m, or can we be told the more important mass or even volume figures? In Olympic-sized swimming pools, natch.
There's meant to be lots of them to detect if a serious effort is made to go looking for them.
A nice round up of the SoA in asteroid stopping is given. here
Bottom line, the only borderline viable method would be to send 2 nukes, one to dig a hole into the object, one to go down it and shatter it. Navigating down a freshly dug hole, having just survived a recent nuclear explosion at (fairly) close range and not detonating till you get to the bottom is quite challenging.
Earth orbit velocity is about 8Km/s, escape velocity is sqrt(2) bigger. Expected oncoming velocity is about 30 Km/s. Landing is not an option.
Bottom line, the only borderline viable method would be to send 2 nukes, one to dig a hole into the object, one to go down it and shatter it.
To quote from the article you linked,
We can't afford to shatter the comet
Knocking chunks off the outside isn't quite the same.
Pedantry aside, that particular bit of analysis was with regards to a 15-50km diameter comet; a 100m diameter body like this one would be straightfoward by comparison, and a substantially more common risk.
Still, here's hoping that the USAF didn't lose all their casaba-howitzer designs when Orion was kicked to the kerb.
I read somewhere an article about how scientists had rather discredited the idea of shattering an asteroid of any size and prefer to push it into another orbit (or "move it away").
That would be because shattering the asteroid would not significantly change its trajectory, so it would be a case of getting hit with buckshot instead of one single bullet. Oh, and the buckshot would be radioactive too.
I understand the reasoning, but I still can't help being a bit disappointed the in lack of any Earth-shattering kabooms in the future of preserving Earth from . . . Earth-shattering kabooms.
I'm probably missing something obvious, but if we shatter it into lots of tiny pieces that then hit us, aren't the smaller bits more likely to burn up in the atmosphere than the one big bit? I mean I'm guessing that wouldn't be great but presumably less bad than one big bit hitting the surface?
4M km gives a cross-sectional area of gazzillions of square km. The earth only has a tiny cross section in comparison.
Python tells me the Earth's cross section is only 1/(4x10^^6) of that of the disc reaching out to this flypast.
With odds like that they can fly past every day and I won't care.
With odds like that they can fly past every day and I won't care.
They do fly past pretty frequently, and for the most part no-one else cares either... a quick look at https://twitter.com/AsteroidMisses suggests we get a rock passing within 10 lunar distances every few weeks or so.
The problem with this one was that it was only spotted when it was already exceedingly close, because we're doing a lousy job of searching and our interception abilties are so primitive that we seriously need easrlier warning in able to do something about any rock that will actually hit us; that's what you should care about.
"So asteroids can be rather dark, huh? Why, that's cheating!"
It's the one we don't see that will get us.
Remember recently when all the world was watching the flyby of the space rock that was inside lunar orbit? Out of nowhere - on the same day - came a second (and apparently 'rather dark') rock and slammed the unsuspecting people in Chelyabinsk, Russia.
Nice trick, there, Universe. Waving the left hand in the air while punching with the right ...