Asteroid 2004 FH

Spaceweather.com ^ | 3/18/2004 | NASA

[Orlando]

Newly-discovered asteroid 2004 FH is going to fly-by our planet TODAY, March 18th , 2200 GMT) 5:08 pm, est. only 43,000 km , which is only 26,500 miles from Earth.

[cogitator]

At that rate I would expect one to hit us every 115 years or so.

The Tunguska event provided last century's hit. We're due for another on that scale. And there have been theories, which I consider somewhat outlandish, that the Peshtigo, Wisconsin fire that occurred on the same day as the Great Chicago Fire was caused by a meteorite event. That wouldn't constitute a major hit, but if true, that would be a hit for that century.

New Evidence (for comet/asteroid theory of fire triggering)

Finally, Earth is 70% ocean. Asteroid impacts hitting the ocean or Antarctica on the scale of a Tunguska may not have been recorded, or if related phenomena were observed and reported they may not be distinguishable from a large volcanic eruption.

[Dave Olson]

The first mistake is in thinking that if we use explosives or nuclear something to convert it from a bowling ball traveling at us at 15,000 miles an hour into a pile of BBs weighing the same as the bowling ball and still traveling at us at 15,000 miles an hour,

True, but there is an atmosphere between us and the object. It may not be enough to burn up something of any significant size that's in one chunk. However, if that object was broken up into small enough pieces that are spread out, each of those pieces would burn up.

Consider that every year, the earth is showered with thousands meteors each about the size of a grain of sand. If all those grains were combined into one large and solid hunk of rock, it could do considerable damage. But because that same amount of rock is in tiny pieces, we're treated to spectacular shows a couple of times a year instead.

[cogitator]

This one (which was also a lot smaller) just missed on August 10, 1972.

I saw the home movie from which this frame was extracted on the evening news.

Here's a description:

Daylight Fireball of August 10, 1972

While one size estimate is as high as 80 meters diameter, the better estimates are 3-14 meters diameter.

[cogitator]

The Tunguska bolide burned up completely

Wouldn't "exploded" be a better description of what happened, considering the 'Ground Zero' upright trees and the knockdown pattern?

[CJ Wolf]

I wonder if they calculated the effect of the moons gravity as well on this. If the diagram is right it might be just enough to pull it in a wee bit further.

[cogitator]

Ever wonder why the moon has so many craters? Some of them seemingly fresh craters? Good thing we have an atmosphere.

Hey Capitan, you referrin' to this?

NASA Solves Moon Mystery
(for other readers, this link has some nice supplemental information and links)

By the way, I looked back at your comment on that thread, and also what was written about the Teton bolide. There's no guarantee that a 20-m object would completely burn up in Earth's atmosphere before impact.

[Orlando]

Here's a update story from the BBC and a image/Picture of Asteriod 2004 HF provided by the Starkenberg Observatory
in Germany.


http://news.bbc.co.uk/1/hi/sci/tech/3523200.stm

It will come close to the Southern Atlantic region, Nasa and others are saying it will miss, but if it does hit earth our atmosphere will destroy the small asteriod,etc...

Is there a chance a Tsunami would occur , if it is destroyed in our atmosphere over the Southern region of the Atlantic ?, If so ? What kind of waves are we looking at ? 5 feet, 10,20 + ???

God, I hope it miss us period !!!!

[jpsb]

If it is only a 100 or so feet accross then there is nothing to worry about with an ocean inpact. Now if it was 1,000 feet accross then a serious wave could result.

[steveegg]

Hmmm...you'd think that a 100 foot diameter asteroid would be down to around 60 feet cubed by the time it impacted.

That would be FAR more than half its mass gone (closer to 80%, actually). A 100-foot diameter asteroid, assuming it's roughly spherical, would have a volume of roughly 520,000 cubic feet (give or take oddities in the shape). A 60-foot diameter asteroid (assuming the same spherical shape) would have a volume of roughly 113,000 cubic feet (the more-accurate number is a result of atmospheric burn-off, which would serve to smooth out the shape, especially if the asteroid had a decent spin on it). The numbers would be different with an oblong/squared-off asteroid, but the principles would be the same.

[ngc6656]

Your question about the orbital period of the asteroid prompted me to use the pre-encounter orbital data to see if there are other close encounters in the near future. I ran it out for 50 years and found the next closest encounter appears to occur 19.99923 years hence: the asteroid would be in the same place in its orbit as it is during its current close encounter; however, Earth in its orbit would arrive at the same as its current position 6 hours and 45 minutes later.

These are just the musings of an incurable number cruncher. As I pointed out in the earlier post to you, the current encounter will change the orbital period of the asteroid by some degree.

[bk1000]

If it lands in the desert, the muslims will probably start praying to it. (Mecca II?)

[Lokibob]

Ever see this one?

---

DOD Satellite Observations

"On 9 December 1997, sensors aboard DOD satellites detected the impact of a meteoroid at 08:15:55 UTC roughly midway between Nuuk and Qaqortoq, Greenland. The object broke into at least 4 pieces. One piece detonated at an altitude of about 46 km at 62.9 degrees North Latitude, 50.9 degrees West Longitude. The remaining 3 pieces detonated in close proximity to one another at altitudes between 28 km, at 62.9 degrees North Latitude, 50.1 degrees West Longitude and 25 km at 62.9 degrees North Latitude, 50.0 degrees West Longitude."

USAF NEWS RELEASE

From:   Headquarters Air Force Technical Applications Center   
        Office of Public Affairs            
        Patrick AFB, Fl.,
        32925-3002
        (407)-494-9915

Date: June 8, 1998

****************************************************************************
On 9 December 1997 at approximately 08:15:55.2 UT, sensors aboard a
U.S. Department of Defense satellite recorded the bright flash of
an apparent meteoroid disintegrating in the atmosphere over
Greenland. The peak radiated intensity recorded on this event 
was 9.5E10 watts/sr (using a 6000K blackbody model for the
radiation). Correspondingly, the total radiated energy of the
event was 2.7E11 Joules.

GOES-8 infrared images on 9 December 1997

Fortunately, Greenland can be seen every three hours in the GOES-8 thermal infrared channel ("I04", or Imager channel 4 at 11 microns) with lower resolution:

GIF animation

coastline map ("+" marks impact point)

[Terriergal]

Newly-discovered asteroid 2004

how "newly" is that?

[RightWhale]

This asteroid is going to pass as close to earth as Kerry is to the Presidency. You'll need binoculars.

[Terriergal]

ping! Get your telescopes warmed up... ;-)

[cd ..]

Here is another way to look at this.
The average velocity of the earth in orbit is 18.5 miles per second.
If the miss is 26500 miles then we miss by about 24 minutes.

Cheers
cd ..

[cogitator]

Yeah, that's very cool (you posted it in the other thread, too). Subsequent expeditions to the area attempted to find an impacting object, but only discovered micrometeorite fragments in meltwater.

[silverleaf]

God to Earth: "Let's just call this one a GIMMEE"

[RightWhale]

we're a long way from being able to do anything about it.

We would need a lead time of at least ten years. Two days just wouldn't cut it. Besides that, we have zero experience of moving the trajectory of any asteroid. I happpen to be in that line of work, so if anyone is serious about this potential problem, they might drop a line.

[Mr. K]

Nobody mentioned what if it hit the oceans. The tidal wave and flash steamed water would affect the whole world