But planetary astronomers believe that the comet may have been pulled into thousands of small chunks.

He returned to Ireland in the 1930s, and became both a published international economist and planetary astronomer.

The plan was to carry an engineer/technician and at least one geologist or planetary astronomer on the flight.

"It would be more helpful if we could use a small nuclear device," the planetary astronomer was saying, totally serious.

The term sol is used by planetary astronomers to refer to the duration of a solar day on Mars.

The hiking analysts were not planetary astronomers, and with this first color picture from Mars they simply mixed the colors until it looked "right."

In the opinion of many planetary astronomers, that distinction belongs to Pluto itself.

But the earliest date that life could have started has been pushed forward by planetary astronomers.

The only one who didn't seem to mind was their planetary astronomer, Harry Chesweiler.

Gene collaborated closely with his wife, Carolyn, a planetary astronomer.