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- Path: sparky!uunet!cis.ohio-state.edu!ucbvax!CMR.NCSL.NIST.GOV!roberts
- From: roberts@CMR.NCSL.NIST.GOV (John Roberts)
- Newsgroups: sci.space
- Subject: Re: Propulsion questions
- Message-ID: <9207231121.AA01655@cmr.ncsl.nist.gov>
- Date: 23 Jul 92 11:21:17 GMT
- Sender: usenet@ucbvax.BERKELEY.EDU
- Organization: National Institute of Standards and Technology
- formerly National Bureau of Standards
- Lines: 26
-
-
- -From: steinly@topaz.ucsc.edu (Steinn Sigurdsson)
- -Subject: Re: Propulsion questions
- -Date: 22 Jul 92 21:35:23 GMT
- -Organization: Lick Observatory/UCO
-
- -[Black hole drive]
-
- -Penrose mechanism. Can't remember actual number but you recover
- -about 30% of rest mass energy. Main problem is that minimum stable
- -mass is uncomfortably heavy - particularly if you want a primordial
- -black hole that's been around a Hubble time - that's if Hawking's
- -right.
- - Of course if he is, and you can _create_ a m < m_HubbleBH
- -black hole you recover almost 100% of the rest mass as it evaporates
- -;-)
-
- Though maybe a little quicker than you'd like. :-)
-
- Interesting system - you have to keep feeding it, whether you need the
- drive or not, or it keeps heating up until it blows your ship to
- smithereens. :-)
-
- John Roberts
- roberts@cmr.ncsl.nist.gov
-
-