WIMPs and MACHOs: 'the most important science in years'

January 23, 1996|By Rick Horowitz

YOU'VE GOT YOUR business meetings, and then you've got your business meetings. All they did at the meeting of the American Astronomical Society was find 40 billion new galaxies and account for half the missing matter in the universe. Oh -- and raise the possibility of life on other planets.

Must have been a fun couple of days.

Did you happen to catch any of those stories coming out of San Antonio, where the stargazers were gathered last week for their latest celestial show-and-tell? Talk about playing ''Can You Top This?'' -- you can't get much topper than these folks.

First up was the more-than-slightly-revised stellar census, courtesy of the much-maligned Hubble Space Telescope. Formerly fuzzy but now firmly focused, the Hubble spent 10 days last month staring deep into space, clicking away at a tiny, but representative, dot of sky.

And when the pictures came back from the drug store? Surprise! Fifteen hundred -- maybe even 2,000 -- galaxies, most of them never seen before. So many, in fact, that the scientists simply tossed away their previous estimates. Ten billion galaxies in the universe? How about 50 billion, each with billions and billions of stars of its own?

Getting crowded out there, you're thinking. You don't know the half of it. Ninety percent of the universe has been missing; the folks at San Antonio think they've finally found a bunch of it. That was the second thing.

You probably didn't realize that 90 percent of the universe was missing. (You probably had all you could handle with the other 10 percent.) But it's true, or at least scientists have believed that it's true. ''Dark matter,'' they call it. Something other than the observable galaxies -- lots of something -- has to be out there, undetected, to make all those formulas about how the universe hangs together come out right. But what?

Something strange and subatomic, some physicists had suggested: ''WIMPs'' -- ''weakly interacting massive particles.'' Something big, others had argued: ''MACHOs'' -- ''massive compact halo objects.'' (Funny guys, those astronomers.)

But they were just theories. As the New York Times' John Noble Wilford (whose own writing on these subjects is always heavenly) put it, ''For astronomers, not being able to find most of the universe has been puzzling and frustrating.'' You bet!

Seven out of a trillion

And now they think they know: It's ''MACHOs'' -- white dwarfs, specifically, burned-out stars impossible to see, but numbering more than a trillion. So far they've found seven -- on the outskirts (or ''halo'') of our very own Milky Way, with gravitational fields strong enough to bend and brighten light rays streaming toward earth from other, living, stars.

The scientists who saw the light figure that all together, the dwarfs could account for 50 percent of the missing ''dark matter'' in the entire universe. (I figure the rest is buried in the cushions of my couch.)

Anyway, if they're right, this is big -- or as another astronomer was saying, it's ''the most important piece of science I've heard of in years.'' Of course, that was before they started talking about life on other planets.

That was the third thing.

You don't want to get your hopes up just yet, but what would you say to the discovery of two planets orbiting around stars not unlike our own sun? Planets close enough -- but not too close -- to those suns for water potentially to exist there in liquid form? Liquid water, the basic jump-start ingredient for life itself?

Pretty amazing, yes? And if there are two planets like that (they've even nicknamed one of them ''Goldilocks'' -- not too hot, not too cold, just right -- scientists now believe there must be others, which only improves the odds that somewhere . . .

Put enough molecules at enough keyboards and someday . . . They could be having their own meetings.

Rick Horowitz is a syndicated columnist. His e-mail address: horowitzomnifest.uwm.edu

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