Return to the table of contents for
the Facts & Faith, Second Quarter
1997 IssueAstronomy enthusiasts among you know that the world’s largest optical telescope is the 400-inch Keck on Mauna Kea, Hawaii. The world’s largest radio telescope is the 1000-foot antenna in Puerto Rico. These are amazing instruments to be sure, but try to imagine one 32,000 kilometers (20,000 miles) across. That’s too big for Earth, you realize. So how is it possible? Ask the Japanese.
Japan’s Institute of Space and Astronomical Science has recently launched a 26-foot diameter radio telescope into an extremely elliptical orbit. This telescope is linked with forty large ground-based radio telescopes.
Such a linkage is useless at optical wavelengths because instabilities in the earth’s atmosphere disturb the incoming light waves. But these instabilities do not disturb radio waves. And with the help of hydrogen maser clocks and computers at each radio telescope site, the signals yield images with much sharper resolution than radio telescopes typically produce. The resolution is equivalent to what would come from a telescope with a diameter as large as the greatest distance between radio telescopes in the array—in this case 32,00O kilometers. This Very Long Baseline Space Observatory (VLBSO) achieves a resolution a thousand times better than the Hubble Space Telescope and a hundred times better than the Hipparcos instrument. With the equivalent resolution, someone in Pasadena, Calif., could see details on a grain of rice in Tokyo.
Best suited for delivering detailed maps of compact, bright sources such as quasars, black holes, and masers (microwave equivalents of lasers), the VLBSO should give us our most precise (to date) look at stars, galaxies, and extremely high energy physics. It can be used to calculate distances more precisely than Hipparcos, which will then become a confirmation tool. The gigantic Japanese instrument promises to give us our best yet measurements of the universe’s size and age, thus our best test for evaluating the accuracy of various creation models.
Observations began in April. Plans also are underway to increase the power of the VLSBO by launching more telescopes out to greater distances. RTB will keep you posted.
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Return to the table of contents for
the Facts & Faith, Second Quarter
1997 Issue