"We are mimicking, more or less, the conditions in the early solar nebula," the giant gas-and-dust cloud that produced the solar system 4.56 billion years ago, said Rutgers University geology graduate student Bosmat Cohen, author of a new study in the August 10 issue of the journal Nature.

"It was kind of funny to hold that dust in my hand and think we are all made of this."

The research sheds light on how dust was melted in the solar nebula to produce a "fiery rain" of droplets or beads called chondrules, which now are found in meteorites.

The study does not reveal whether chondrules were formed by heat from huge solar flares, lightning bolts or collisions between increasingly larger objects in the young solar system.

But whatever happened, it cooked the dust for different periods of time to produce the various chemical compositions now seen in meteorite chondrules, according to Cohen and her coauthors, geology professor Roger Hewins and former research scientist Yang Yu.

"Its very important work," said chemist Derek Sears, director of the University of Arkansas Center for Space and Planetary Science. "One of the biggest questions facing us is how did planet Earth, the solar system and us form? Weve got incredibly little hard evidence to address that question."

He called Cohens study "good solid work. We are getting a better handle on conditions that prevailed when the solar system was young."

Meteorites are leftovers from the newborn solar system. Chondrules, or solidified beads or droplets of fiery rain, make up about 80 percent of the biggest class of meteorites -- the ordinary chondrites that include the chondrules surrounded by a matrix of finer-grained rock.

"Whatever formed these beads was an extremely important process" in the young solar system, Sears said. "The question is, What was it? Chondrules are highly diverse in composition. If we can get information on how they came to be highly diverse, then we have an important clue."

Cohen said dust formed as the early solar nebula of gas cooled somewhat.

"The problem is how do we get all these grains of dust to make planets?" she asked. "Chondrules might have been the link between dust and larger objects."

Chondrules and remaining dust gradually were swept together to form asteroids and ultimately planets, she explained.

Cohen said many scientists believe quick "flash heating" melted the dust to form chondrules. It was thought dust would have to be heated to different temperatures to produce chondrules with various chemical compositions. Yet solar flares, lightning and impact shocks all would produce similar temperatures, Cohen and colleagues wrote.

Their experiment showed cooking dust for varying lengths of time at a single temperature can produce the various chemical compositions of chondrules.

Cohen mixed minerals to create a dust with the same elemental composition as the early sun, solar system and meteorites.

"It was kind of funny to hold that dust in my hand and think we are all made of this."

The researchers pressed the dust into pellets, then put the pellets into a vacuum furnace at 2,880 degrees Fahrenheit (1,580 degrees Celsius) with hydrogen gas at one ten-thousandth Earths normal atmospheric pressure.

The furnace mimicked solar-nebula conditions, except for the presence of gravity, Cohen said.

The pellets were baked for one to 18 hours. The longer a dust pellet baked, the more components evaporated from it, changing its chemical composition.

The resulting chondrule-like crystals had chemical compositions reflecting those of real meteorite chondrules.

Cohen said whatever heated the dust flares, lightning, impacts or shock waves from large passing objects might have happened quickly, but clouds of dust and gas could have held residual heat for hours.

"We believe all these are the heating mechanisms," she said. "We dont prefer one over the other."

Sears, however, doubted open space even in a dusty nebula would stay hot enough for up to 18 hours to bake dust into chondrules with various chemical compositions.

"I would argue chondrules formed on asteroids" when the space rocks were hit by other large objects and shrouded in heat-retaining dust and gas, Sears said. "Youd get a crater, and the bottom of that crater was lined by melt [from the heat of impact]. In almost zero gravity, the melt would disperse as fine droplets. Theyd go into orbit and rain down."

In the 1800s, British scientist Henry Sorby invented the method of examining thin sections of rock through a microscope. Sorby described chondrules within meteorites as "droplets of fiery rain from the sun," Sears said.

While the sun did not spit chondrules out, "the entire solar system is droplets of the same kind of material as the sun," Sears said. "We are all from the sun."