Astronomers Discover Planet Building is Big Mess | Aero-News Network
Aero-News Network
RSS icon RSS feed
podcast icon MP3 podcast
Subscribe Aero-News e-mail Newsletter Subscribe

** Airborne 11.19.14 ** HD iPad-Friendly -- Airborne 11.19.14 **
** Airborne 11.17.14 ** HD iPad-Friendly -- Airborne 11.17.14 **
** Airborne 11.14.14 ** HD iPad-Friendly -- Airborne 11.14.14 **

Wed, Oct 20, 2004

Astronomers Discover Planet Building is Big Mess

Takes A Long Time To Cook One Up

Planets are built over a long period of massive collisions between rocky bodies as big as mountain ranges, astronomers announced last week.

New observations from NASA's Spitzer Space Telescope reveal surprisingly large dust clouds around several stars. These clouds most likely flared up when rocky, embryonic planets smashed together. The Earth's own Moon may have formed from such a catastrophe. Prior to these new results, astronomers thought planets were formed under less chaotic circumstances.

"It's a mess out there," said Dr. George Rieke of the University of Arizona, Tucson, first author of the findings and a Spitzer scientist. "We are seeing that planets have a long, rocky road to go down before they become full grown."

Spitzer was able to see the dusty aftermaths of these collisions with its powerful infrared vision. When embryonic planets, the rocky cores of planets like Earth and Mars, crash together, they are believed to either merge into a bigger planet or splinter into pieces. The dust generated by these events is warmed by the host star and glows in the infrared, where Spitzer can see it.

The findings will be published in an upcoming issue of the Astrophysical Journal. They mirror what we know about the formation of our own planetary system. Recent observations from studies of our Moon's impact craters also reveal a turbulent early solar system. "Our Moon took a lot of violent hits when planets had already begun to take shape," Rieke said.

According to the most popular theory, rocky planets form somewhat like snowmen. They start out around young stars as tiny balls in a disc-shaped field of thick dust. Then, through sticky interactions with other dust grains, they gradually accumulate more mass. Eventually, mountain-sized bodies take shape, which further collide to make planets.

Previously, astronomers envisioned this process proceeding smoothly toward a mature planetary system over a few million to a few tens of millions of years. Dusty planet-forming discs, they predicted, should steadily fade away with age, with occasional flare-ups from collisions between leftover rocky bodies.

Rieke and his colleagues have observed a more varied planet-forming environment. They used new Spitzer data, together with previous data from the European Space Agency's Infrared Space Observatory and the joint NASA, United Kingdom and the Netherlands' Infrared Astronomical Satellite. They looked for dusty discs around 266 nearby stars of similar size, about two to three times the mass of the Sun, and various ages. Seventy-one of those stars were found to harbor discs, presumably containing planets at different stages of development. But, instead of seeing the discs disappear in older stars, the astronomers observed the opposite in some cases.

"We thought young stars, about one million years old, would have larger, brighter discs, and older stars from 10 to 100 million years old would have fainter ones," Rieke said. "But we found some young stars missing discs and some old stars with massive discs."

This variability implies planet-forming discs can become choked with dust throughout the discs' lifetime, up to hundreds of millions of years after the host star was formed. "The only way to produce as much dust as we are seeing in these older stars is through huge collisions," Rieke said.

Before Spitzer, only a few dozen planet-forming discs had been observed around stars older than a few million years. Spitzer's uniquely sensitive infrared vision allows it to sense the dim heat from thousands of discs of various ages. "Spitzer has opened a new door to the study of discs and planetary evolution," said Dr. Michael Werner, project scientist for Spitzer at NASA's Jet Propulsion Laboratory, Pasadena (CA).

"These exciting new findings give us new insights into the process of planetary formation, a process that led to the birth of planet Earth and to life," said Dr. Anne Kinney, director of the universe division in the Science Mission Directorate at NASA Headquarters, Washington. "Spitzer truly embodies NASA's mission to explore the universe and search for life," she said.

FMI: www.spitzer.caltech.edu

Advertisement

More News

Barnstorming: FAA -- The Original EPA

The Governmental Death By 1000 Cuts, Continues... Guest Editorial by Rich Davidson, Grass Cutting Administrator At Lee Bottom Flying Field/API Advisory Board Did you feel that Aero>[...]

Financier Says Heathrow Expansion Easier To Fund Than Gatwick

Ian Hannam Backs Heathrow Hub U.K. financier Ian Hannam, one of the backers of Heathrow Hub, has said that Gatwick would find it much more difficult to fund expansion than either o>[...]

AD: Boeing Company

AD NUMBER: 2014-23-04 PRODUCT: Certain The Boeing Company Model 777-200LR, -300, -300ER, and 777F series airplanes.>[...]

AD: Bombardier, Inc. Airplanes

AD NUMBER: 2014-23-06 PRODUCT: Certain Bombardier, Inc. Model CL-600-2B19 (Regional Jet Series 100 & 440) airplanes.>[...]

ANN's Daily Aero-Linx (11.21.14)

Alaska Airman's Association The Alaska Airmen's Association is the largest state general aviation group in Alaska. It is a non-profit 501 (c) 3 organization whose sole purpose is t>[...]

blog comments powered by Disqus



Advertisement

Advertisement

Podcasts

Advertisement

© 2007 - 2014 Web Development & Design by Pauli Systems, LC