Evening Lectures on Migrating Planets, Hazardous Asteroids Search

University of Arizona ^ | September 4, 2009 | University Communications

[SunkenCiv]

The University of Arizona Lunar and Planetary Laboratory is launching its Fall 2009 Evening Lecture Series with talks on wandering solar system planets and searches for hazardous asteroids from Mount Lemmon... Planetary sciences professor Renu Malhotra will speak on "Migrating Planets" on Tuesday, Sept. 15. [whoops] Did the solar system always look the way it is now? New studies by Malhotra and others find that the outer planets -- Jupiter, Saturn, Uranus and Neptune -- were more tightly clustered in the early solar system, then moved away from each other. Malhotra's models show that as the solar system evolved, Jupiter moved slightly closer to the sun, while the other giant planets moved farther apart from each other and farther away from the sun. The migration likely perturbed asteroids that contributed to the heavy bombardment of the inner solar system. The evidence is recorded as close as the moon and as far away as Pluto.

Catalina Sky Survey director Ed Beshore will talk on "The Search for Hazardous Asteroids from Mount Lemmon" on Tuesday, Oct. 20. On Oct. 5, 2008, the UA's Catalina Sky Survey discovered a small asteroid named 2008 TC3. It is the first asteroid discovered with a 100 percent certainty of colliding with Earth. Just 17 hours after Catalina Sky Survey team member Rich Kowalski discovered 2008 TC3, it fell harmlessly in the desert of northern Sudan. During those 17 hours, amateur and professional astronomers made more than 570 observations of the asteroid. Months later, U.S. and African students and researchers recovered more than eight pounds of meteorites from the fall. Beshore will also talk about how the Catalina Sky Survey searchers for dangerous asteroids, and some ideas about what might be done if an Earth-threatening asteroid is found.

[SunkenCiv]

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[SunkenCiv]

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[cripplecreek]

Wow. That’s like 3 days in a row I’ve stumbled across something about “wandering” planets.

I read an old article yesterday about planetary mass objects that aren’t gravitationally bound to a star.

[Quix]

Thanks.

Curious . . . sobering.

Particularly given the Biblical prediction of a large mountain falling into the sea in these END TIMES.

[SunkenCiv]

probably a dead link:

Rogue Planet Find Makes Astronomers Ponder Theory
by Maggie Fox
October 5, 2000

Eighteen rogue planets that seem to have broken all the rules about being born from a central, controlling sun may force a rethink about how planets form, astronomers said on Thursday... "The formation of young, free-floating, planetary-mass objects like these is difficult to explain by our current models of how planets form," Zapatero-Osorio said... They are not linked to one another in an orbit, but do move together as a cluster, she said... Many stars in our own galaxy, the Milky Way, may have formed in a similar manner to the Orion stars, she said. So there could be similar, hard-to-see planets floating around free near the Solar System.

[cripplecreek]

What got me thinking about deep space wanderers was the creationist thread about a planet with a retrograde orbit. In my opinion there are only two physical likelihoods.

the planet was hit by a very large object that started it to orbiting the opposite direction of the star or it came from deep space from a direction opposite the star’s rotation and was captured. Retrograde orbits aren’t all that unusual and there is at least one moon in our solar system that orbits in a retrograde orbit around its planet.

Who knows, frozen planets between the galaxies may be the norm.

[SunkenCiv]

If there’s a planet in retrograde orbit, it is generally considered diagnostic of capture. If a group of moons (for example) are all moving in retrograde (sort of the case with the moons of Uranus, nice example eh?) it probably means the planet rolled over at some point, perhaps due to a large impact.

[SunkenCiv]

The rest of the Renu Malhotra keyword:

• Planet-Forming Disks Might Put the Brakes on Stars
• Assessing the massive young Sun hypothesis to solve the warm young Earth puzzle [preprint abstract]
• Astronomers Discover Apparent "Outer Edge" To The Solar System [2000]
• Are Planetary Systems Filled to Capacity?
• The Curious Case of Missing Asteroids
• Asteroid #2 down; on to Asteroid #1!