Asteroid 'gives Earth a close shave' on Monday

[DrDNA]

An asteroid of a similar size to a rock that exploded above Siberia in 1908 with the force of a thousand atomic bombs whizzed close past Earth on Monday, astronomers said on Tuesday.

 

2009 DD45, estimated to be between 21 and 47 meters (68 and 152 feet) across, raced by at 1344 GMT on Monday, the Planetary Society and astronomers' blogs reported.

 

The gap was just 72,000 kilometers (44,750 miles), or a fifth of the distance between Earth and the Moon and only twice the height of satellites in geosynchronous orbit, the website space.com said.

 

The estimated size is similar to that of an asteroid or comet that exploded above Tunguska, Siberia, on June 30 1908, flattening 80 million trees in a swathe of more than 2,000 square kilometres (800 square miles).

 

2009 DD45 was spotted last Saturday by astronomers at the Siding Spring Survey in Australia, and was verified by the International Astronomical Union's Minor Planet Centre (MPC), which catalogues Solar System rocks.

 

The closest flyby listed by the MPC is 2004 FU162, a small asteroid about six metres (20 feet) across which came within about 6,500 kms (4,000 miles) of us in March 2004.

 

http://www.breitbart.com/article.php?id=CNG.783c3aae6eb418393fc6f8c443ef6765.2f1&show_article=1

[Airbrush]

Hopefully the next Tunguska-sized event will happen somewhere safe, but most likely it will hit an ocean and the Tsunamis could be devastating. What is more likely is a smaller one, hopefully it will be just big enough to wake us up to the reality of those objects. Then I dread our poor economic situation because the new imperative will be to defend against those objects, which will cost a LOT.

[Fedace]

Does this mean IN 2012, we could be hit by one of these big ones ? Even though, NASA, explicitely said in 2007 that there is No rock of any significant size heading our way ???

[Airbrush]

The story above did not say exactly when this asteroid was first discovered. It sounded like it was first discovered last Saturday. How often do objects that large appear catching us by surprize only a couple days before closest encounter?

 

"No rock of any significant size" means what size?

 

If the world was going to end in a year from now, would it be possible to supress that knowledge from the general public? It would result in total anarchy and social break down.

[DrDNA]

The story above did not say exactly when this asteroid was first discovered.

"2009 DD45 was spotted last Saturday by astronomers at the Siding Spring Survey in Australia"

[iNow]

That's what happens when you cut funding to projects like NASAs Near Earth Object (NEO) program.

 

http://neo.jpl.nasa.gov/

[Severian]

It is not really much of a close shave; it was still over 11 times the radius of the Earth away.

 

Since the area goes like the square, even if you fired asteroids at the earth randomly within the radius of the 'close shave' asteroid, you would on average hit the planet one time in 130. So if a close shave like this happens even every 100 years we will still have 13,000 years to wait before one hits.

[cameron marical]

i dont know... thats pretty freaky that people dont know when an asteroid of any size relatively close to the earth. what if that asteroid was just a little too close and we got hit by it? thatd suck!

[Airbrush]

That story means that objects that big come that close to us before we even know they exist.

 

Last I heard is that Tunguska-sized impacts occur about once every 500 - 1,000 years. Long before that I heard they happen once every 100 years, but that must be way off. Such impacts would have been widely recorded throughout history. Anyone heard of any different frequencies?

[cameron marical]

we should have some satelittes a little bit out there to send back like a live feed showing asteroids or something like that. motion activated...

[Airbrush]

Motion detection is exactly how they find those things. Doing that from a network of satelites sounds like a great idea. Why don't they do that?

[Sisyphus]

Motion detection is exactly how they find those things. Doing that from a network of satelites sounds like a great idea. Why don't they do that?

 

You're asking why they don't have millions of high-powered orbital telescopes whose sole function is to point in every possible direction looking for incoming rocks?

[Airbrush]

"Millions of high-powered orbital telescopes"? Certainly the reason we don't is COST and economic priorities. But when a smaller one hits us somewhere, which is likely in our lifetimes, then public opinion can change 180 degrees. Not millions of orbital telescopes, but dozens for starters, and more can come on line in the future.

[Sisyphus]

"Millions of high-powered orbital telescopes"? Certainly the reason we don't is COST and economic priorities. But when a smaller one hits us somewhere, which is likely in our lifetimes, then public opinion can change 180 degrees. Not millions of orbital telescopes, but dozens for starters, and more can come on line in the future.

 

Yes, cost was what I was implying. The point being that "detecting motion" is a lot easier said than done. You want to see an object at the edge of the solar system, you better be looking directly at it with a really powerful telescope, long enough to notice that something is wrong. And you can only look at tiny, tiny slice of sky at once. Remember, they're still discovering planet-sized objects out there, let alone a rock a few dozen meters across.

 

Also, on what basis are you saying it's likely that we'll be hit by something in our lifetimes that will cause enough damage to shift public opinion enough to devote such enormous resources to preventing a repeat?

[DrDNA]

That story means that objects that big come that close to us before we even know they exist.

 

Last I heard is that Tunguska-sized impacts occur about once every 500 - 1,000 years. Long before that I heard they happen once every 100 years, but that must be way off. Such impacts would have been widely recorded throughout history. Anyone heard of any different frequencies?

 

Ever hear the story of the statistician that calculated that the average depth of the river was 3 ft, then drowned while trying to cross it?

 

One impact could happen today and another one tomorrow and the average of many impacts over a great length of time might still be one every 500-1000 years.

 

Of course, as you suggest, the numbers could be way off also.

Maybe we have been plummeted by big rocks at much greater frequency.

I believe that this scary scenario is entirely plausible if most of them blow up at elevation before impact.......leaving no large impact crater but devastating none the less.

[cameron marical]

The point being that "detecting motion" is a lot easier said than done. You want to see an object at the edge of the solar system, you better be looking directly at it with a really powerful telescope, long enough to notice that something is wrong. And you can only look at tiny, tiny slice of sky at once. Remember, they're still discovering planet-sized objects out there, let alone a rock a few dozen meters across.

.

 

couldnt you use laser reflection to do just that. kind of like a trip wire, have two wires and two recievers next to those, reasonably far out in space, and have them constantly beaming them at each others recievers, and if theres a rock of any size coming in, bigger, the more likely detected, itll will have a disruption if the constant feedback. then it can send a signal back to earth and voila, we know an asteroid is near. just have, oh, well, id say about maybe 12 pairs of these, and you can cover alot of the space around earth. theyd be quite spaced out, but lasers do travel at the speed of light...

they could be powered by solar of course, so it wouldnt take extra energy after theyre up.

 

and if this sounds like one of the stupidest ideas youve ever heard, two things"

A: screw you

 

B: just keep in mind what einstein said, "imagination is more important than knowledge".

and just go a little easy on me. for i am but a boy:-)

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Merged post follows:

Consecutive posts merged

id say some type of detection is worth it, no matter what way, compared to the consequince of any asteroid hitting earth.

[Airbrush]

...on what basis are you saying it's likely that we'll be hit by something in our lifetimes that will cause enough damage to shift public opinion enough to devote such enormous resources to preventing a repeat?

 

We are being hit by smaller ones every day, the question is when will one big enough (at least 10% the size of Tunguska) to cause significant damage hit us? Nobody knows but it COULD happen in our life times. Maybe not as likely as I made it sound.

 

I don't know about "enormous resources to prevent a repeat" but public opinion would force governments to devote substantial resources to the threat.

 

The main threat from the smaller ones would be tsunamis from an ocean impact. I propose that everyone living near the ocean should have an underground tsunamic shelter. You beachfront dwellers should start digging.

[DrDNA]

I propose that everyone living near the ocean should have an underground tsunamic shelter. You beachfront dwellers should start digging.

 

I see your point.

Everyone has been doing it backwards for thousands of years.

In a flood we should head for the lowest point possible.

Edited March 4, 2009 by DrDNA

[Sisyphus]

.couldnt you use laser reflection to do just that. kind of like a trip wire, have two wires and two recievers next to those, reasonably far out in space, and have them constantly beaming them at each others recievers, and if theres a rock of any size coming in, bigger, the more likely detected, itll will have a disruption if the constant feedback. then it can send a signal back to earth and voila, we know an asteroid is near. just have, oh, well, id say about maybe 12 pairs of these, and you can cover alot of the space around earth. theyd be quite spaced out, but lasers do travel at the speed of light...

they could be powered by solar of course, so it wouldnt take extra energy after theyre up.

 

Not really sure what you mean.

 

and if this sounds like one of the stupidest ideas youve ever heard, two things"

A: screw you

 

B: just keep in mind what einstein said, "imagination is more important than knowledge".

and just go a little easy on me. for i am but a boy:-)

 

Not the stupidest idea, no (that's a very high bar), but...

 

I'm not really clear on what you're describing. If it's just a laser tripwire, then objects would only be detected if they passed directly between two stations, which would make it pretty much useless, considering the distance involved (Imagine a cage with bars 100 million miles apart. What can it hold?). And even if that weren't an issue, say if you could somehow detect anything that passed through a plane defined by three stations, there's still at least two more problems. One, getting them out there (where "out there" is defined as far enough away from the Earth to offer good enough warning to actually do something about it, let's say a fairly arbitrary minimum of 500 million miles), and two, getting them into orbits where they all stay put relative to one another and to the Earth (or at least the Sun, if they're far enough away). And even if all of this is possible, you still have to show how it's potentially easier and/or more effective than looking around with telescopes.

 

So yeah, screw me and keep thinking, but remember that it is the approval of curmudgeonly naysayers that gives new ideas legitimacy.

[Airbrush]

I see your point.

Everyone has been doing it backwards for thousands of years.

In a flood we should head for the lowest point possible.

 

Seriously, for most coastal dwellers, there would be no time to reach high ground to escape a series of waves over 100 feet high. In a standard flood you would be better off finding high ground. Impact-induced tsunamis are a different scenario entirely. Roads would quickly become massive parking lots. Your best hope would be underground in a personal shelter. Within a few hours the waters should subside so you can exit. Your house will be gone, and the shelter hatch will be covered with debris, so it will take some digging out. The entrance to the shelter should zigzag so you exit horizontally through a vertical doorway using tools you stashed inside.

Edited March 4, 2009 by Airbrush

[Sisyphus]

Or we can all live in arks.

[insane_alien]

...Within a few days the waters should subside.../quote]

 

fixed that for you. its not going to be as quick as you think.

[DrDNA]

Last time I checked with my plumber he told me in no uncertain terms that water flows down hill.

 

So, unless the underground tsunami shelter is a Navy surplus submarine and/or it has scuba gear inside, I'm headed in the opposite direction.

[Airbrush]

Mr. Alien, you are correct, it could take days or hours depending on the magnitude of the event.

 

Dr DNA, you may be right, depending on how much time you have and your escape route options. Just build the thing watertight. The hatch should open INwards in case it is blocked from the outside. You should have a saw and ax, along with an assortment of tools, to cut your way out, and there should be a portal so you can see if you are still under water.

 

On the other hand, you might get around the traffic jams on a off-road motorcycle, like the kid in Deep Impact.

Edited March 5, 2009 by Airbrush

[DrDNA]

The hatch should open INwards in case it is blocked from the outside. You should have a saw and ax, along with an assortment of tools, to cut your way out, and there should be a portal so you can see if you are still under water.

 

Forget the tools.

If the thing is water tight, and the door opens inwards, it should open soon enough without any assistance.