Astronomy/Space; Black Holes

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Expert: - 7/13/2010


Question
Hi Tom. I would like you to confirm if this statement is correct followed by a question. A black hole with the mass of a billion tons would have a horizon between 10-15 meters and if it were to approach earth it would place itself at the center of the core without us noticing it. Is this true? If so what mass does a black hole need to be to consume the earth? Tony, London, England UK

Answer
Hi Tony,
Not being a math major, I really don't know.  But I do know that a billion tons is practically
nothing, mass-wise, so you're dealing with what Stephan Hawking would call a mini-black hole,
and I would think that the event horizon is much smaller than say, 10 meters.

In any case, it's my understanding that anything entering a black hole (irrespective of what initial size it is) is consumed immediately and forever, so I would think that the Earth and it's surroundings would be consumed even way before your black hole arrives at "what was"... the center of the Earth, growing and consuming all the time until you now have a new black hole that contains one Earth-size mass.  Just my opinion though. And I would think ANY black hole of ANY size (merging with the Earth, or any other body) would be completely fatal and cause total annihilation to any planetary body.  (What's going to stop it from growing larger and consuming the mass of the entire planet)?  Nothing.
Clear Skies,
Tom Whiting
Erie, PA USA  

Astronomy

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Tom Whiting

Expertise

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

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:http://www.velocity.net/~bwhiting 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.

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

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