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Soyuz docking
The Russian Soyuz TMA-5 capsule successfully docks to the International Space Station, delivering the Expedition 10 crew for its half-year mission. (3min 21sec file)
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Docking in full
This longer-length broadband clip follows the Soyuz TMA-5 capsule's approach and docking to the station's Pirs module. (8min 47sec file)
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Post-docking news conference
Russian and U.S. space officials hold a post-docking press conference from the mission control center outside Moscow. (23min 04sec file)
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Launch of Expedition 10
The Russian Soyuz rocket blasts off from Baikonur Cosmodrome carrying the Expedition 10 crew International Space Station for a six-month mission. (2min 25sec file)
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Launch in full
This longer-length broadband clip follows the launch of Expedition 10 from the final minute of the countdown through deployment of the Soyuz capsule from the third stage. (10min 15sec file)
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The State Commission
The State Commission hears from senior Russian and American officials before giving final approval to launch Expedition 10 to the International Space Station. (13min 46sec file)
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Astronomers discover planet building is big mess
NASA NEWS RELEASE
Posted: October 18, 2004

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

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.


This animation illustrates a massive collision between rocky, embryonic planets as big as mountain ranges. Such collisions form the basis of the planet-building process. New findings from NASA's Spitzer Space Telescope show that these catastrophes continue to occur around stars even after they have developed full-sized planets, when they are as old as one hundred million years. For reference, our own Sun, at 4.5 billion years old, is far past this late stage of planet formation. Credit: NASA/JPL
 
"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.


This animation depicts colliding rocky bodies in an early planetary system. Such collisions form the basis of the planet-building process. New findings from NASA's Spitzer Space Telescope show that these catastrophes continue to occur around stars even after they have developed full-sized planets, when they are as old as one hundred million years. For reference, our own Sun, at 4.5 billion years old, is far past this late stage of planet formation. Credit: NASA/JPL
 
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 Astronomical Satellite and the joint NASA, United Kingdom and the Netherlands' Infrared Space Observatory. 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 (JPL), Pasadena, Calif.

"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.

JPL manages the Spitzer Space Telescope for NASA's Science Mission Directorate.

Ares 1-X Patch
The official embroidered patch for the Ares 1-X rocket test flight, is available for purchase.
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Apollo Collage
This beautiful one piece set features the Apollo program emblem surrounded by the individual mission logos.
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Expedition 21
The official embroidered patch for the International Space Station Expedition 21 crew is now available from our stores.
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Hubble Patch
The official embroidered patch for mission STS-125, the space shuttle's last planned service call to the Hubble Space Telescope, is available for purchase.
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