NASA research on a meteorite has provided new evidence that the inner planets formed from materials spread far and wide in the early solar system, and not just from nearby matter.Oxygen isotopic measurements in the core and outer rim of a calcium-aluminum-rich inclusion contained in the Allende meteorite record the entire range of oxygen isotopic composition previously measured in all solids in the solar system.The research provides the first measurements to show that early forming solids experienced vastly varying environments during the planet-forming period of our solar system. The study substantiates ideas that the terrestrial planets - Earth, Mars, Mercury and Venus - formed as a result of materials accreting from various sources across the protoplanetary disk rather than from just a nearby region. The findings will be published online March 4 in the journal Science.
Scientists have performed a micro-probe analysis of the core and outer layers of a pea-sized piece of a meteorite some 4.57 billion years old to reconstruct the history of its formation, providing the first evidence that dust particles like this one experienced wildly varying environments during the planet-forming years of our solar system.The researchers interpret these findings as evidence that dust grains travelled over large distances as the swirling protoplanetary nebula condensed into planets. The single dust grain they studied appears to have formed in the hot environment of the sun, may have been thrown out of the plane of the solar system to fall back into the asteroid belt, and eventually recirculated back to the sun.
The solar system could be almost two million years older than previously thought, scientists have discovered using evidence from one of the oldest meteorites. Researchers revised the age after analysing a mineral "relic" buried deep within the meteorite, known as an inclusion, found in the Sahara desert in northwest Africa.These minerals, from a 1.49-kilo meteorite found in the Moroccan desert in 2004, are among the oldest solid materials formed following the birth of the Sun.
When the planets in our Solar System first formed, they were swimming through a disk-shaped cloud of gas. Their passage roiled and compressed the gas, and the gravity of the compressed gas in turn pulled on the proto-planets. The original models suggested that the net effect would have been to drag the proto-planets inward - and while the drag would have stopped as the gas eventually dissipated, it would have been too late. They would long since have fallen into the Sun.But those early models didn't take into account the fact that compressed gas heats up, which limits how dense it can become, and in turn limits how hard its gravity can pull on the proto-planets. Beyond that, the planets' own gravity would fling gas around - the same sort of phenomenon NASA counts on when a spacecraft on its way to Saturn, say, gets a slingshot velocity boost from Jupiter on the way.
Lead-lead (Pb-Pb) dating is among the most widely used radiometric dating techniques to determine the age of really old things, such as the age of the Earth or the Solar System. However, recent advances in instrumentation now allow scientists to make more precise measurements that promise to revolutionize the way the ages of some samples are calculated with this technique.