Astronomical discovery to be announced soon

Press, 3 November 1983, Page 14

Astronomical discovery to be announced soon

By

Robert Cooke

of the “Boston Globe”

A big surprise in astronomy — the discovery of a huge ring surrounding the entire solar system — will be announced soon by scientists controlling a new space satellite. Details of the discovery, not yet disclosed by N.AJSA., are scheduled to be announced on November 9 at a news conference at the National Air and Space Museum in Washington, a spokesman for the space agency said. The discovery is considered important because it may help scientists understand how the solar system was formed from a cloud of gas and dust 4.6 billion years ago. Since Galileo aimed the first telescope at the stars and planets in 1610, this huge ring has never been seen.

“As I understand it,” an astronomer at Harvard University said, “the team (of astronomers) has found that the Sun has a ring” that circles the solar system beyond the planet, Pluto. The ring is estimated to be 9.3 billion miles from the Sun.

A scientist at a different observatory said that "there appears to be a ring of substantial thickness” beyond Pluto. He said it was either “a ring that is tilted up outside the plane of the ecliptic, or it is stuff that’s just spewed all around.” It was suspected, he said, that the ring material seen by the LR.A.S. satellite (In-fra-Red Astronomy Satellite) consisted of relatively large particles, bigger than air gun pellets. This was evident because of the type of light, long-wave infra-red signals, received by the satellite instruments.

“My guess,” the scientist said, “is that it is some sort of debris associated with comets.”

Both scientists asked not to be identified because the space agency has gone to great lengths to maintain secrecy. In addition to the ring, N.A.SA. is expected to announce a whole range of other I.R.A.S. discoveries on November 9. These will include new stars with dark materials in orbit around them, strange clouds of dust in space, and infra-red objects in other galaxies.

Listed high among I.R.A.S.’ achievements already is the discovery that one of the brightest stars in the sky, Vega, is surrounded by a cloud of debris. This means Vega could have a solar system in the process of formation. This discovery substantially raised the odds that planets are a normal phenomenon near stars. If there are many planets, the chances that life exists elsewhere are improved. The I.R.A.S. spacecraft, which scans the sky for signals in the infra-red, or heat, portion of the spectrum, was launched last January. Its mission should end in about a month, when it runs out of its supply of liquid helium, which is used to cool heat-sensing instruments.

I.R.A.S. is a joint project by scientists from the United States, Great Britain, and the Netherlands.

The secrecy surrounding the new I.R.A.S. results was imposed by the National Aeronautics and Space Administration, and many astronomers are critical because the findings have not been released yet. “This is the tightest-kept thing I have seen,” one scientist complained. “I cannot imagine them being able to keep it so long.” There was a report from Japanese observers several weeks ago that a ring had

been discovered much closer to the Sun, but astronomers interviewed later said that that result was not widely accepted.

Because no information has been released on the new discovery, astronomers are unable to guess what materials the ring might be made of. Those who have had glimpses of the data, however, say the particles are probably rock fragments.

If that is true, the ring is probably not very similar to the bright and beautiful set of rings surrounding the planet, Saturn. Instead, the ring may be more like the recently discovered rings circling the planet, Uranus. These are so dark that they may consist mainly of carbon.

According to an astronomer, Kenneth Brecher, of Boston University, the discovery of this ring around the solar system may help discover what it is that perturbs, or slightly alters, the orbit of the planet Neptune.

“It has been claimed that all the perturbations on Neptune are not accounted for by Pluto,” Mr Brecher said. More recent calculations indicate that Pluto is less massive than originally believed, which means “perturbations of the orbit of Neptune have to be explained by something else.”

In other words, Pluto is not big or dense enough to give Neptune much of a gravitational “kick” at closest approach. “So now," Brecher said, “they are coming along with something else,” the ring, “which maybe can explain that extra perturbation. This is an open problem that may be touched on by that observation.”