Dansk udgave - Danish Edition
The Astronomy Class at AGS High School -Denmark
Asteroid Movie : Potentially Hazardeous Asteroid 1998 WT24 .
About 350 asteroids have been classified as "potentially hazardous" - due to their orbit bringing them into close approach to our planet Earth.
One asteroid which gets astronomically very close - is the recently discovered WT24 - here racing across the Gemini Constellation on Dec 11 (40 x 50 sec : '20:47:16 UT until '21:13:33' UT ) .
Photographers - our students on their own - in particular : Lars T. Mikkelsen, Thomas Balstrup, Mikkel M. Mortensen and Rasmus Lind - working with an AP6 CCD attached to a 5 " APO pb mounted at a 16" SCT - image processing : Maxim.
These young photographers have now collected all together 150 images (of each 50 seconds) together into a
Movie:
200x150-divx.avi (120 KB)
,
400x300-divx.avi (350 KB)
,
800x600-divx.avi (1,47 MB)
,
raw-divx.avi (3,05 MB)
These files are dramatically compressed due to DivX-codec - which now also is required to view the clips.
This requires WIN 98 or later - the installation of DivX-codec - free for personal use - to be found at http://www.divx.com/divx/
If you do instead prefer the old direct to use AVI versions - the file sizes are like follow :
250x166 Format AVI 7,5 Mbyte
,
500x333 Format AVI 30 Mbyte
FILM-DATA : during these 150 exposures - the fast asteroid WT24 moves more than 0,5 Degree (e.g. the angular extension of our Full Moon). Dec 11 -150x50 sec - 2 hours from 201052UT to 222424 UT
Movie:
200x150-divx.avi (120 KB)
,
400x300-divx.avi (350 KB)
,
800x600-divx.avi (1,47 MB)
,
raw-divx.avi (3,05 MB)
These files are dramatically compressed due to DivX-codec - which now also is required to view the clips.
This requires WIN 98 or later - the installation of DivX-codec - free for personal use - to be found at http://www.divx.com/divx/
If you do instead prefer the old direct to use AVI versions - the file sizes are like follow :
250x166 Format AVI 7,5 Mbyte
,
500x333 Format AVI 30 Mbyte
FILM-DATA : during these 150 exposures - the fast asteroid WT24 moves more than 0,5 Degree (e.g. the angular extension of our Full Moon). Dec 11 -150x50 sec - 2 hours from 201052UT to 222424 UT
Dec 13
10 x 50 sec - 21:12:07UT until 21:20:16UT - really moving fast..
Photographers: Lars T. Mikkelsen, Thomas Balstrup, Rasmus Lind, Mads J.N. Clausen, Marie Bach Grønbæk and Kim Lorenzen
JPL NASA has a very interesting 3D JAVA model of this asteroids orbit. .
WT24 will be at it closest approach at December 15-16 - where radio telescopes at Goldstone, California, and Arecibo, Puerto Rico, will carefully monitor this object. Read NASA-s Press Release Coordinates may be found at e.g. IAU
The orbital period of WT24 is merely 7 months - the precise size is unknown - but within the range of kilometers.
It is quite easy to show - that impacts of this kind of heavy object do posses a huge kinetical energy.
Calculations / Impact Energy Estimate : RELAX - there is NO DANGER - a collision will NOT happen. However - let us make a few energy calculations.. If this object is e.g. spherical with say 20 km radius - the total volume will be 33 EE12 = 33 000 000 000 000 cubic meter. Applying a typical meteorite density equal to 2,8 ton pr cubicmeter - the total mass will thus equal 9,4 EE16 kg.
Applying the high accuracy ephemeride - the speed within an Asteroid - Earth collision may be estimated as 35000 km pr hour - approx 10 000 meter pr sec ! - which equals 4,7 EE 24 Joule. 1 Megaton TNT is 4,5 EE15 Joule - so this is about 1000 Million Megaton TNT. It is estimated that a global Nuclear War would imply the devastating detonation of 10 000 Megatons TNT - source : WORLDWIDE EFFECTS OF NUCLEAR WAR - - - SOME PERSPECTIVES U.S. Arms Control and Disarmament Agency, 1975. . So - strictly speaking - we do have a released energy equal to 100 000 global atomic wars - see also the data within the Cheney Report.
Divided at a population equal to 5000 million people - this would be 0,2 Megaton - or 75 Hiroshima bombs pr human individual.
These results are of course sensitive to the input data given - results much less - and even much larger - may also appear.
So - with all respect - in case it should happen - a few Hollywood atomic bombs will probably be of no help at all.
WT 24 has already given rise to some press articles - e.g. ABC NEWS
However : The risk of these large objects impacting appears extremely small - maybe at a level of once within millions of years.
At a geological timescale however - objects like WT24 have been impacting - with disastreous results.
Ron Baalke has a very informative webpage on this topic..
Interesting articles and sites :
"Killer Asteroids: The Count Rises " Sky & Telescope - News Nov 22, 2001
Visit SPACEWEATHERS WT24 Video collection.
