Asteroid 2005 YU55

[snowNH]

Anyone here any news about this asteroid? Its going to pass between the Moons orbit and the earth's orbit on 11/9/11.

Another interesting tidbit, is that the EAS testing system is doing a mandatory national test on 11/9/11 for the first time ever. Coincidence?

[Ellinwood]

Coincidence?

Yes.

[wxmeddler]

http://neo.jpl.nasa.gov/news/news171.html

Level 1 or "Normal" on the Tornino Scale..

[wxmeddler]

[Roger Smith]

Here's another view of the orbit of this asteroid.

http://ssd.jpl.nasa....2005+YU55&orb=1

From this data, you can see that the asteroid is presently inside the earth's orbit and will cross our orbit behind but also somewhat above the earth during the close encounter, by the time of closest approach it will be heading further out into the solar system therefore slowing down relative to the earth (today it is travelling faster than the earth) as well as rising to a higher position relative to our orbital plane (although not as high as Mars will then be, so it won't come close to Mars, from which it may well be an escaped satellite). On its closest approach to the Sun it crosses the orbit of Venus and in some cases would be very close to that planet. Some other interesting data given, the inclination to our orbit is a mere 0.51 deg which is very small for an asteroid, the period is 446 days, and the size is given as 0.4 kms. We would not want that hitting our planet or even the Moon, even if you could choose the location.

Comparing to the Penn State diagram, the logic of that diagram is not entirely clear but the straight line through the earth must be the earth's orbit rather than the earth-sun line since the Moon is full just after the date of this encounter (Nov 10, 2017z). I am surprised to see the asteroid depicted as crossing the earth's orbit at right angles when the other source shows such a small angle of approach of about 5-10 deg. However, as the diagram is fixed on the earth's position this may be an optical illusion. If the Penn State diagram was moving it should look as though the asteroid just misses the earth and slows down relative to our speed. As shown, it is also above our orbital plane and that of the Moon although the Moon is also above our orbital plane at this time. According to the JPL diagram, this is about as close as we can come to the asteroid, its nodal positions are not in our orbital path. However, it comes close to three different planets and the Moon in its orbit and so could get perturbed out of its current orbit rather easily over thousands of years. So it's one of those nasty ones that we may one day have to deal with.

[snowNH]

Does anyone know of a diagram that shows different sizes of meteors and what they will do if it hits the earth?

[Roger Smith]

Impact would partly depend on composition but as only rocky meteorites survive (icy ones are more likely to shatter explosively, possibly what happened in Siberia in 1908), the impact of objects smaller than 5-10 metres is likely to be localized damage, but the Arizona meteor crater (a mile wide and hundreds of feet deep) was apparently the result of a 50-metre wide meteorite hitting, then the 100-mile wide Manicouagan crater in Quebec was caused by a 5-km wide asteroid and the Yucatan event asteroid often cited as the cause of mass extinctions caused a crater 250 miles wide and is postulated to be 10 kms wide. These data must be treated as very approximate, but it gives you the general idea that once a meteorite (tiny asteroid in smaller cases) gets larger than a house, it gets into the range of kinetic energy required to blast out a crater. If anything much bigger than 10 kms ever hit the earth (large asteroids are 100-1,000 miles wide) there might be more than just a big crater, the planet could explode. I don't know what the survivable limit would be, likely about 50-80 miles. There are probably a thousand or more asteroids that large. This is probably what happened to the planet that was between Mars and Jupiter before the asteroid swarm was created, or perhaps it was pulled apart by tidal forces from Jupiter. The largest asteroid, Ceres, is about half the diameter of the Moon. It is out around 2.75 A.U. on average. But there are currently no known asteroids larger than 10 kms that come anywhere near the Earth. One of these, Eros, sometimes comes within 0.15 A.U. as it will in March 2012. But it is always found outside the earth's orbital distance. Apparently something about the size of Eros hit the earth to cause the Yucatan mass extinction event.

Just taking a linear extrapolation of those three examples, this object 2005 YU55 would blast out a crater ten to twenty miles wide if it hit the land surface of the earth. I don't think this would create a massive dust cloud or firestorm on the scale of the mass extinction, but it might create a planetary dust veil of climatic significance. It would certainly obliterate an area hundreds of miles in extent. But if it hit the ocean somewhere, that could create a massive tidal wave. 2005 YU55 is almost ten times larger than the Arizona object, and ten times smaller than the Quebec object.

[Hailstorm]

Roger, I appreciate your insight in this thread with all this information. Seeing how some of your findings are intimidating and disturbing, do you believe all of the nations around the globe would be equipped with the right technology; cooperate together; and successfully deflect an extinction-level event asteroid that would have a very high chance of impacting Earth? I've seen the movie Armageddon and wonder if the methods (blowing up the core of the asteroid using a nuclear weapon) used in that movie to deflect the asteroid would be viable.

[turtlehurricane]

Impact would partly depend on composition but as only rocky meteorites survive (icy ones are more likely to shatter explosively, possibly what happened in Siberia in 1908), the impact of objects smaller than 5-10 metres is likely to be localized damage, but the Arizona meteor crater (a mile wide and hundreds of feet deep) was apparently the result of a 50-metre wide meteorite hitting, then the 100-mile wide Manicouagan crater in Quebec was caused by a 5-km wide asteroid and the Yucatan event asteroid often cited as the cause of mass extinctions caused a crater 250 miles wide and is postulated to be 10 kms wide. These data must be treated as very approximate, but it gives you the general idea that once a meteorite (tiny asteroid in smaller cases) gets larger than a house, it gets into the range of kinetic energy required to blast out a crater. If anything much bigger than 10 kms ever hit the earth (large asteroids are 100-1,000 miles wide) there might be more than just a big crater, the planet could explode. I don't know what the survivable limit would be, likely about 50-80 miles. There are probably a thousand or more asteroids that large. This is probably what happened to the planet that was between Mars and Jupiter before the asteroid swarm was created, or perhaps it was pulled apart by tidal forces from Jupiter. The largest asteroid, Ceres, is about half the diameter of the Moon. It is out around 2.75 A.U. on average. But there are currently no known asteroids larger than 10 kms that come anywhere near the Earth. One of these, Eros, sometimes comes within 0.15 A.U. as it will in March 2012. But it is always found outside the earth's orbital distance. Apparently something about the size of Eros hit the earth to cause the Yucatan mass extinction event.

Just taking a linear extrapolation of those three examples, this object 2005 YU55 would blast out a crater ten to twenty miles wide if it hit the land surface of the earth. I don't think this would create a massive dust cloud or firestorm on the scale of the mass extinction, but it might create a planetary dust veil of climatic significance. It would certainly obliterate an area hundreds of miles in extent. But if it hit the ocean somewhere, that could create a massive tidal wave. 2005 YU55 is almost ten times larger than the Arizona object, and ten times smaller than the Quebec object.

Thankfully this rock is missing by a good bit. This is certainly a humbling event though, it tells us that things aren't safe out there.

[Roger Smith]

Well, don't forget that these massive craters were formed over a very long period of time, there hasn't been a significant crater formed during human history and the Arizona crater is thought to be over 50,000 years old. The Yucatan event was 65 million years ago. So I think the current level of international response is rational. Considerable effort has been made to identify all problem asteroids. Discussions are underway about the "what if" scenario at some unknown future time should a dangerous collision be predicted. We really don't have the technology to do anything about such an event at this point in time, and I suppose we should, but the chances are very small that such technology would ever be required, well maybe not "ever" but in the next hundred years the chances must be a lot smaller than one in a thousand, even if we define dangerous as just a small impact crater of half a mile which could well turn into a non-event if it missed populated areas. So my personal opinion is, the action now being taken is probably all we could reasonably expect, although a technology to deflect problem asteroids would be a good thing. The alternative of blowing them up just creates quantities of space junk that could be problematic on a different scale. Deflection will be tough, as you can see with this asteroid, they tend to be approaching us at odd angles and high rates of relative velocity, getting that much power or energy in place presumably quite some distance from the earth would be straining our space abilities at the present time even if it were an urgent matter. The fact that there's no particular threat known to us makes it hard to plan the details.

[Dark Energy]

I love the movie Deep Impact.

[turtlehurricane]

Well, don't forget that these massive craters were formed over a very long period of time, there hasn't been a significant crater formed during human history and the Arizona crater is thought to be over 50,000 years old. The Yucatan event was 65 million years ago. So I think the current level of international response is rational. Considerable effort has been made to identify all problem asteroids. Discussions are underway about the "what if" scenario at some unknown future time should a dangerous collision be predicted. We really don't have the technology to do anything about such an event at this point in time, and I suppose we should, but the chances are very small that such technology would ever be required, well maybe not "ever" but in the next hundred years the chances must be a lot smaller than one in a thousand, even if we define dangerous as just a small impact crater of half a mile which could well turn into a non-event if it missed populated areas. So my personal opinion is, the action now being taken is probably all we could reasonably expect, although a technology to deflect problem asteroids would be a good thing. The alternative of blowing them up just creates quantities of space junk that could be problematic on a different scale. Deflection will be tough, as you can see with this asteroid, they tend to be approaching us at odd angles and high rates of relative velocity, getting that much power or energy in place presumably quite some distance from the earth would be straining our space abilities at the present time even if it were an urgent matter. The fact that there's no particular threat known to us makes it hard to plan the details.

I believe by the time the real threat comes we'll be ready, we'll know at least a decade ahead of time so we'll have time to plan, and as you describe it won't be for many more years. Also, even though an astroid has alot of force, it is governed by simple gravitational equations and we can likely find a way to deflect it or destroy it, even with nuclear weapons.

Honestly, if humanity got destroyed by a rock that would be anti-climatic.

[NaoPos]

I wanna see them ahoot some nukes at it! Maybe came at it from the rear?!?!

Seriously thoug, could be a decent chance at actually seeing what could be effective in the future to deter an imminent strike.

[dendrite]

Does anyone know of a diagram that shows different sizes of meteors and what they will do if it hits the earth?

You really need to make use of Google more.

[Roger Smith]

The media are probably going to miss the point of the three-dimensional encounter. The asteroid does not pass "between the earth and the Moon" nor would it do so if the Moon were back a few days in its orbital cycle. The separation is mostly in the z axis, the best way to visualize what's going to happen is that the asteroid will whiz over top of the north poles of the earth and Moon, but more precisely, it will do that relative to where the Earth and Moon were in space about six hours earlier. Picture the situation as a truck and a car speeding down the freeway, the car is very slowly overtaking the truck on the right, then suddenly a bird flies across the freeway at a diagonal, at almost the speed of the car, and just behind the truck and then just behind the car, but almost above the rear portions of each.

This is roughly what will happen on November 8th - 9th. The "miss" will be more due to the bird's elevation in flight than its position relative to the freeway.

[Roger Smith]

Despite the wording of the original post in this thread, the close encounter actually happens TODAY and is timed for 2328z (6:28 pm EST, 5:28 CST, 4:28 MST, 3:28 PST). At about 0600z the asteroid will be at its closest point to the Moon. Although it will only be visible in telescopes, observers in the eastern time zone would find the asteroid high in the south at sunset, moving rapidly to the left towards Taurus over the following three hours. Observers in the Pacific time zone (mostly clouded out anyway) would find the asteroid after sunset much closer to the rising nearly full moon. The later views for astronomers in eastern Asia would show the asteroid rapidly receding into the region of the sky to the east of (to the right visually) of the Moon, the trajectory will not take it behind or past the Moon in the next week, since the Moon is making westward progress faster than the asteroid at all times (relative to the earth). The asteroid would likely become invisible to all but the most powerful telescopes after a few days.

As of time of writing (2135z) the asteroid is already within the orbital sphere defined by the lunar orbit, if you could visualize that in three dimensions, and traversing the north polar segment of that sphere from sunward to space-ward with a rising trajectory.

[PennyForYourThoughts]

events.slooh.com If you visit this site, they have a countdown clock to the nearest approach to earth (about 3 hours and 14 minutes from now) and will have a live presentation during that time. They are replaying past events on the site at this time.