[meteorite-list] meteor velocity
From: GeoZay_at_aol.com <GeoZay_at_meteoritecentral.com>
Date: Thu Apr 22 10:27:47 2004 Message-ID: <161.27f8d9ef.2ce2f375_at_aol.com> -------------------------------1068603765 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit In a message dated 11/11/2003 2:32:52 PM Pacific Standard Time, josecamposcomet_at_netcabo.pt writes: >>I suppose that the Earth's gravitational attraction onto these meteoroids would not account too much, on their slow, or very fast relative velocities?<< Well...the earths gravitational attraction does effect a meteor when it enters the atmosphere. This tends to accelerate the meteor towards the center of the earth. For a meteor shower, the meteor will give the appearance of radiating from a region slightly shifted towards the zenith, in relation to the stream it's part of. This is known as Zenithal attraction. For faster meteors the shift is less than for slower meteors. >>On a slightly different matter: What would you think that, considering its ~60 Ton mass, the great HOBA meteorite's entry velocity might have attained on atmosphere entry?<< Probably in the neighborhood of 11 to 18 km/s...just a guess. >> And why was it that most of it, did no desintegrate to smaller fragments? Was it because of a very low velocity? (which implies an asteroidal origin).<< Maybe? And perhaps due to it's strong structure with few fractures, if any, for breakups to occur? >>And what could possibly might have been its trajectory angle in relation to the ground? (a very low angle, in order not to become half-buried and/or not to break-up on impact?).<< Perhaps a very low angle... >>Even at a lower minimum velocity of some 11 km/s, why is is that it did not made a small hole/crater on the ground? (unless if its vestiges have been eroded with time, bearing in mind it's estimated 80.000 yrs since it fell to the ground).<< Maybe it did at the time, but as you pointed out, has long ago eroded away? GeoZay -------------------------------1068603765 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable <HTML><HEAD> <META charset=3DUTF-8 http-equiv=3DContent-Type content=3D"text/html; charse= t=3Dutf-8"> <META content=3D"MSHTML 6.00.2800.1106" name=3DGENERATOR></HEAD> <BODY style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial; BACKGROUND-COLOR: #fffff= f"> <DIV>In a message dated 11/11/2003 2:32:52 PM Pacific Standard Time, josecam= poscomet_at_netcabo.pt writes:</DIV> <BLOCKQUOTE style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue=20= 2px solid"> <DIV><FONT face=3DArial size=3D2>>>I suppose that the Earth's gravitat= ional attraction onto these meteoroids would not account too much, on t= heir slow, or very fast relative velocities?<<</FONT></DIV></BLOCKQUOT= E> <DIV>Well...the earths gravitational attraction does effect a meteor when it= enters the atmosphere. This tends to accelerate the meteor towards the cent= er of the earth. For a meteor shower, the meteor will give the appearance of= radiating from a region slightly shifted towards the zenith, in relation to= the stream it's part of. This is known as Zenithal attraction. For fas= ter meteors the shift is less than for slower meteors. </DIV> <BLOCKQUOTE style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue=20= 2px solid"> <DIV><FONT size=3D2></FONT><FONT face=3DArial></FONT> </DIV> <DIV><FONT face=3DArial size=3D2>>>On a slightly different matter: Wha= t would you think that, considering its ~60 Ton mass, the gre= at HOBA meteorite's entry velocity might have attained on atmosphere en= try?<<</FONT></DIV></BLOCKQUOTE> <DIV>Probably in the neighborhood of 11 to 18 km/s...just a guess.</DIV> <BLOCKQUOTE style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue=20= 2px solid"> <DIV><FONT face=3DArial size=3D2>>> And why was it that most of it, di= d no desintegrate to smaller fragments? Was it because of a very low ve= locity? (which implies an asteroidal origin).<<</FONT></DIV></BLOCKQUO= TE> <DIV>Maybe? And perhaps due to it's strong structure with few fractures, if=20= any, for breakups to occur?</DIV> <BLOCKQUOTE style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue=20= 2px solid"> <DIV><FONT face=3DArial size=3D2>>>And what could possibly might have=20= been its trajectory angle in relation to the ground? (a very low angle,= in order not to become half-buried and/or not to break-up on impact?).<&= lt;</FONT></DIV></BLOCKQUOTE> <DIV>Perhaps a very low angle...</DIV> <BLOCKQUOTE style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue=20= 2px solid"> <DIV><FONT face=3DArial size=3D2>>>Even at a lower minimum velocity of= some 11 km/s, why is is that it did not made a small hole/crater on the gro= und? (unless if its vestiges have been eroded with time, bearing in min= d it's estimated 80.000 yrs since it fell to the ground).<<</FONT= ></DIV></BLOCKQUOTE> <DIV>Maybe it did at the time, but as you pointed out, has long ago eroded a= way?</DIV> <DIV>GeoZay</DIV> <BLOCKQUOTE style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue=20= 2px solid"> <DIV><FONT face=3DArial size=3D2></FONT> </DIV></BLOCKQUOTE> <DIV></DIV></BODY></HTML> -------------------------------1068603765-- Received on Tue 11 Nov 2003 09:22:45 PM PST |
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