An opportunity like this comes once, maybe twice, in a planetary scientist's lifetime, says Curt Niebur, a NASA program scientist assigned to the Clipper mission.
The evolution age of proto-planetary nebulae is ~103 years and the lifetimes of planetary nebulae is about 20 000 to 40 000 yr.
The manner in which gas is removed from a protoplanetary disk, he explained, may also "have as much influence on the ultimate configuration of the planetary system as does the lifetime of the disk".
"Clearly it was a once-in-a-lifetime opportunity," said Peter Brown, a planetary scientist at the University of Western Ontario who led one of the two studies in Nature.
"Clearly it was a once-in-a-lifetime opportunity," said Peter Brown, a planetary scientist at the University of Western Ontario who led one of the two studies in Nature and worked on both.
The problems are familiar by now: they include a planetary warming that, while slow on the scale of a human lifetime, is extremely rapid on a geologic time scale, the scientists said.
More than 95% of such clusters tend to dissipate in about 100 million years, the study authors pointed out – just a fraction of a typical star's lifetime – blown out in part by the same forces that would have removed clustered stars' planetary debris.
Dr Robin Russell-Jones Chair, Planetary SOS.
More vivid: Planetary meltdown.
2. Bad planetary alignment.
The heliocentric planetary model (c.
