Astronomy/Comet mass


Thanks for your answer on comets losing mass.
Given  the statement "a comet is the closest that something can be to nothing, and still be something", is the potential damage of a direct impact with Earth due to its velocity?

Yes, the velocity is the big factor. Recall the kinetic energy equation where KE equals 1/2 times the mass times the velocity SQUARED. Just like a vehicle going 70.7 mph has twice as much energy as a car going only 50 mph - (5000 versus 2500 when you square the velocity... and KE triples at 86.6 mph). Double the velocity to 100 mph and it's 4 times the KE you had at 50 mph.
As far as mass, even though a comet nucleus is a very low density body, a cubic mile of frozen water ice with dust, frozen gases, etc... still has a mass exceeding a little more than 10 Kg!  ;-)  (Picture trying to tow a cubic mile iceberg through the water... not the easiest thing to do.)
Clear Skies,


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Tom Whiting


Astronomy has been my hobby/pasttime for over 50 years.  Currently own 3 telescopes, the largest of which is a 30 inch Newtonian truss Dob that is portable.I taught Astronomy/Meteorology at the University Level for 13 years before retiring in 1995. Being retired and home most of the time, I am able to answer all questions relatively quickly, unless it's a new moon weekend with good observing conditions.  No astrology questions please, or questions about alleged UFO picture identifications.


Experience: Astronomy has been my hobby and study for over 50 years. We currently now own a 30 inch portable telescope (Updated - Pennsylvania`s largest portable telescope). It can be seen on our website at: and also attend several regional starparties during the year, and have been on 5 total solar eclipse expeditions.

Organizations: President, Erie County Mobile Observers Group for over 15 years.

Publications: Wrote the "Over Erie Skies" newspaper article in our local newspaper for 11 years (1975-86).

Education: Masters Degree- Taught at the University level for 13 years. Retired 20 years -USAF Pilot - KC-135 with 180 combat missions;  Also Eagle Scout, Philmont staff 2 Yrs, Order of Arrow Lodge Chief, Ham Radio (inactive).

Awards: two discoveries: The mini-coathanger asterism in Ursa Minor (the little dipper) And the mini-ladle- another asterism in the bowl of Ursa Minor. Clients: Currently President of the ECMOG as mentioned above.

BS  Metallurgical Engineering Grove City College, PAMaster's Degree, Gannon University, Erie, PA Also retired USAF pilot, 20 years.

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