Posted on 02/02/2006 9:44:25 AM PST by SunkenCiv
Meanwhile, the Doppler discovery of extrasolar planets orbiting very close to their parent stars has raised a different problem. Many of the planets are so close to their stars (<0.1 AU), and so hot, that they cannot be supposed to have formed where we now observe them. By inference, they could have formed at larger distances (several AU) and then migrated inwards. What would cause this inward migration? As with the solar system case, the root cause may be an exchange of angular momentum with material surrounding the planets at their formation. In particular, if the extrasolar planets formed in massive disks, then torques between the planets and the disks could drive the former inwards.
Aha, you say, why did they stop? There are several possible answers to this question (including the most brutally honest one "we don't know"). Indeed, they might not have stopped, in the sense that the observed close-in extrasolar planets could be the survivors from a now-defunct armada of planets that plopped into their stars never to be seen again. In this case, what we see is what was left behind after the planetary accretion disk dissipated and the tidal torques disappeared. Another possibility is that inward migration stopped when the planets reached the inner edge of the planetary accretion disk, because then the torques acting to propel them inwards would vanish.
(Excerpt) Read more at ifa.hawaii.edu ...
Adding Mercury to Mars would be helpful. Cooling Venus could be started now, but would take thousands of years (at least).
Oh, was going to suggest we get going on this tomorrow, but if it will take that long we better start this afternoon.
I've got it. We'll meditate, and send cooling thoughts toward the planet. ;')
When I see planet Venus, I see with real estate broker's eyes.
re: 55 Cancri
Astronomy Picture of the Day 09-01-04
NASA | 09-01-04 | Robert Nemiroff and Jerry Bonnell
Posted on 09/01/2004 9:34:45 AM PDT by petuniasevan
http://www.freerepublic.com/focus/f-chat/1204850/posts
related:
Massive Object Calls Planet Discoveries into Question
Space dot com (via Yahoo) | Thu, Jan 20, 2005 | Robert Roy Britt
Posted on 01/21/2005 9:19:56 AM PST by SunkenCiv
http://www.freerepublic.com/focus/f-chat/1325494/posts
Scientific maverick's theory on Earth's core up for a test
SF Chronicle | Monday, November 29, 2004 | Keay Davidson
Posted on 12/05/2004 11:17:28 AM PST by SunkenCiv
http://www.freerepublic.com/focus/chat/1294934/posts
The July 2002 issue of Discover had this article:
The Strange Case of the Iron Sun
by Solana Pyne
In the late 1960s, chemist Oliver Manuel made a small but staggering discovery about meteorites. He noticed that the abundances of certain elements in meteorites were distinctly different from those in the Earth and much of the solar system. This observation spurred research showing that our solar system probably formed from material generated in many different stars. For Manuel, it also spawned a radical theory about the origins of our solar system, which he has doggedly pursued for forty years. Nearly all astronomers agree that the Sun and the rest of the planets formed from an amorphous cloud of gas and dust 4.6 billion years ago. But Manuel argues, based on his compositional data, that the solar system was created by a dramatic stellar explosion--a supernova--and that the iron-encased remnant of the progenitor star still sits at the center of the Sun.
11 posted on 12/05/2004 6:04:50 PM PST by SunkenCiv
http://www.freerepublic.com/focus/chat/1294934/posts?page=11#11
:') Those property data sheets in the info boxes on the for sale signs would burn right up. ;')
Someone once suggested on a space blog that we move Venus to the opposite side of Earth's orbit so that it is exactly Earth's distance, but opposite the sun, then make Mars a moon of Venus, and terraform both.
Wild idea, but would make for a cool sci-fi movie.
It would take a lot of planning so as to not disturb earth's orbit during the move. The most stable station points would be 60 degrees before or after earth's position.
Not to mention one buttkicker of a rocket engine.
Sun Might Have Exchanged Hangers-On With Rival StarEither encounter would also leave alien planetoids in our solar system (and some of ours in the alien system) orbiting at a steep angle to the plane in which the planets go around. And so the next step is to search for such objects.
by Dennis Overbye
NY Times
December 2, 2004
Sedna itself has only a moderately inclined orbit , the astronomers say. A more likely candidate for an extra-solar origin is another icy wanderer, known as 2000 CR105, about half the size of Sedna, discovered out beyond Neptune in 2000. Its orbit is inclined 20 degrees to the planets.
The detection of objects with inclinations of 40 degrees or more, the authors write in Nature, "would clinch the case for extrasolar objects in the solar system."
maybe a space list ping? Not like me to neglect that, I'm always buggin' you with pings.
Anyway, a related topic you've posted:
The most earthlike planet yet
Astronomy | 02/02/06 | Francis Reddy
Posted on 02/02/2006 5:27:18 PM PST by KevinDavis
http://www.freerepublic.com/focus/f-news/1570611/posts
http://www.astronomy.com/asy/default.aspx?c=a&id=3922
Extrasolar planet discoveries, various links:
list of all or most:
http://obswww.unige.ch/~naef/who_discovered_that_planet.html
more about Barnard's star here:
http://www.public.asu.edu/~sciref/exoplnt.htm
Gliese 876 discoverers, among other things:
http://exoplanets.org/
from 2002:
http://www.space.com/scienceastronomy/astronomy/exoplanet_scoreboard_020628.html
speaking of Mercury...
Was Mercury a ‘hit-and-run’ planet?
MSNBC Space News | Jan. 11, 2006 | By Robert Roy Britt
Posted on 01/25/2006 10:26:47 PM PST by Swordmaker
http://www.freerepublic.com/focus/f-chat/1565199/posts
The Growing Habitable Zone: Locations for Life Abound
Space.com | 07 February 2006 | Ker Than
Posted on 02/07/2006 1:59:24 PM PST by tricky_k_1972
http://www.freerepublic.com/focus/news/1573798/posts
Astronomers poised to apply novel way to look for comets beyond Neptune
EurekAlert | 7-Jan-2003 | Anne Stark
Posted on 11/07/2005 10:41:04 PM PST by SunkenCiv
http://www.freerepublic.com/focus/f-chat/1517866/posts
NASA telescope spots two mega solar systems
ap on San Diego Union Tribune | 2/8/06 | AP
Posted on 02/08/2006 3:53:01 PM PST by NormsRevenge
http://www.freerepublic.com/focus/news/1574695/posts
Spitzer Sees the Aftermath of a Planetary Collision
Universe Today | Jan. 10, 2005 | Dolores Beasley and Gay Yee Hill
Posted on 01/13/2005 8:50:18 PM PST by SunkenCiv
http://www.freerepublic.com/focus/f-chat/1320521/posts
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