Anything About Everything

14 August 2005

Study: Shining Sun Helped Form Solar System

Filed under: Science,Space — rajiv @ 11:55 am

As first appeared on MSNBC Technology & Science / Space

Updated: 3:40 p.m. ET Aug. 11, 2005

WASHINGTON – Our sun was already shining brightly more than 4.5 billion years ago, as dust and gas was swirling into what would become the planets of the solar system, U.S. researchers reported on Thursday.

They said their finding is the first conclusive evidence that the so-called protosun affected the developing solar system by emitting enough ultraviolet energy to catalyze the formation of organic compounds, water and other elements necessary for the evolution of life on Earth.

“The basic question was, ‘Was the sun on or was it off?’” said Mark Thiemens of the University of California San Diego, who led the study.

“There is nothing in the geological record before 4.55 billion years ago that could answer this.”

So Thiemens and colleagues studied chemical “fingerprints” preserved in primitive chondrite meteorites.

Specifically, they report in Friday’s issue of the journal Science, they looked at isotopes, chemical variants, of sulfide compounds.

Astronomers believe that wind from the protosun blew matter from the core into the flat accretion disk — the layer of gas and matter from which meteorites, asteroids and planets later formed.

It is no good looking for anything on Earth, which has undergone extensive change since it was formed. But primitive meteorites have been less subject to chemical reactions since they were formed.

The UCSD team determined that a slight excess of one isotope of sulfur, called 33S, suggests that there were photochemical reactions going on when the little chunks of meteorite coalesced.

“This measurement tells us for the first time that the sun was on, that there was enough ultraviolet light to do photochemistry,” Thiemens said in a statement. “Knowing that this was the case is a huge help in understanding the processes that formed compounds in the early solar system.”

Now the researchers plan to use their technique to look for other elements in more meteorites and find out more about how the solar system formed.
Copyright 2005 Reuters Limited. All rights reserved. Republication or redistribution of Reuters content is expressly prohibited without the prior written consent of Reuters.

Did Catastrophe Strike A Sun Like Ours?

Filed under: Science,Space — rajiv @ 11:50 am

As first appeared on MSNBC Technology & Science / Space

“Did catastrophe strike a sun like ours?
Scientists detect a cosmic dust-up 300 light-years from Earth

Updated: 9:29 p.m. ET July 20, 2005

WASHINGTON – A dust-cloaked star very much like our sun may have been the site of a cosmic catastrophe involving collisions between asteroids, comets or even planets, scientists reported Wednesday.

Astronomers believe many stars had dust around them during the early stages of planet formation — but this particular star is an adolescent. Its dust is warm and very close to the star, about the same distance away as Earth is from the sun.

“The most likely explanation is that there were two really massive planet-sized objects — about the size of Earth and Mars — that collided with each other and spewed a huge amount of dust into interplanetary space,” said Benjamin Zuckerman, a co-author of an article in Thursday’s issue of the journal Nature.

“It must have been something really violent like that,” Zuckerman said by telephone from the University of California at Los Angeles.

Our own planetary system is no stranger to such violence. Some astronomers theorize that the early Earth was struck by a Mars-sized object that generated a monster magma fountain, some of which condensed to form the moon.

But that was probably in Earth’s infancy, when it was perhaps tens of millions of years old; the star in question is likely hundreds of millions of years old, still younger than Earth’s estimated age of 4.5 billion years or so.

The immense amounts of dust close to the star — known as BD+20 307 — suggest that other planets may also be lurking, UCLA scientists said in a statement.

Because the dust is pulverized into tiny particles, scientists believe the cosmic catastrophe may have occurred within the last several thousand years, an eye blink in terms of cosmic time.

“This star is a real exception,” said Zuckerman. “For something the age of this star, there’s nothing comparable.”

The dusty star is about 300 light-years from Earth, relatively close by cosmic standards. A light-year is about 6 trillion miles, the distance light travels in a year.

It has about the same mass as our sun and is about as bright, the scientists said.
Copyright 2005 Reuters Limited. All rights reserved. Republication or redistribution of Reuters content is expressly prohibited without the prior written consent of Reuters. ”