The Smithsonian Institution contributes to national aerospace goals through the activities of the Smithsonian Astrophysical Observatory (SAO) in Cambridge, Massachusetts, and the National Air and Space Museum (NASM) in Washington, D.C. SAO conducts a broad program of research in astronomy, astrophysics, Earth and space sciences, and science education. NASM, in addition to offering extensive research and education programs, serves as the primary repository for the archives and artifacts of space exploration and discovery.
Successfully deployed from the Space Shuttle in July 1999, the Chandra X-ray Observatory has been orbiting Earth and sending back a steady stream of spectacular x-ray images. Images of objects obtained by Chandra's detectors, including the High Resolution Camera designed by SAO, are received at the Operations Control Center operated for NASA by SAO in Cambridge. SAO is also the site of the Chandra Observatory Science Center, which coordinates research of the space observatory and receives and archives its data for the world astronomical community.
By observing the transits of a suspected planet in front of the star HD209458, SAO astronomers have taken a giant step toward learning about the nature of planets outside our solar systemtheir size, mass, and density. These observations, made initially by a graduate student advisee of an SAO scientist, marked the first time that astronomers had directly detected an extrasolar planet, in this case by watching its shadow cross the disk of a Sun-like star. The precise observations allowed astronomers to determine that the suspected planet is a "gas giant," with a density somewhat less than that of Saturn in our own solar system and a size about one-third greater than Jupiter's.
The popular image of nascent planetary systems as thin, spinning pancakes of cosmic dust and debris may be changed by a new computer model that shows how that disk of debris is transformed into a very distinct ring once Pluto-like bodies start to form. By analyzing Hubble Space Telescope images of a suspected young planetary system recently discovered around the star HR 4796A, SAO scientists and their colleagues produced a computer model that suggests the ring around that object probably is a common feature of all planetary systems. Indeed, the well-known Kuiper Belt of asteroids in our own solar system may even be the residual remains of such a ring.
Launched from a Pegasus-XL vehicle on December 5, 1998, the SAO-designed Submillimeter Wave Astronomy Satellite (SWAS) is the first spaceborne observatory to operate at submillimeter wavelengths and has been giving astronomers new clues to some old cosmic mysteries, including how starsand their accompanying planetsare born. For example, SWAS discovered that large amounts of water seem to pervade the interstellar medium, with particularly copious amounts in the huge molecular clouds thought to be the incubators of newborn stars. By contrast, SWAS has so far failed to detect molecular oxygen in those same interstellar clouds. However, in this case, no news may be perceived as good news, because the apparent absence of molecular oxygen, a byproduct of slow chemical "aging processes" in these clouds, may actually help astronomers to determine their ages.
For nearly four decades, solar scientists have been puzzled by the fact that the high-speed portion of the solar wind travels twice as fast as predicted by theory, with some particles reaching velocities of 2 million miles per hour as they stream out of the Sun and wash over the entire solar system. Now, observations made with instruments built by SAO and flown aboard NASA's Spartan 201 spacecraft and the international Solar and Heliospheric Observatory (SOHO) have revealed a surprising explanation for this mystery: magnetic waves propel the particles through the corona like surfboarders riding the crests of a cosmic sea. The Sun's outermost atmosphere, or corona, is an extremely tenuous, electrically charged gas that is seen from Earth only during a total eclipse of the Sun by the Moon, when it appears as a shimmering white veil surrounding the black lunar disk. Using ultraviolet coronagraph spectrometers on Spartan and SOHO to create artificial eclipses, SAO scientists detected rapidly vibrating magnetic fields within the corona that form magnetic waves that, in turn, seem to accelerate the solar wind. The electrical charges of the solar wind particles, or ions, force them to spiral around the invisible magnetic lines. When the lines vibrate, as they do in a magnetic wave, the spiraling ions are accelerated out and away from the Sun. Indeed, SAO scientists believe there are magnetic waves in the corona with many different "wiggling periods," or frequencies. Thus, these waves can accelerate various solar wind particles at different rates. For example, SAO researchers found, surprisingly, that the heavier oxygen ions actually move faster than the lighter hydrogen ions.
On July 20, 1999, Vice President Al Gore presented the Smithsonian Institution's Langley Medal to the Apollo 11 astronauts in commemoration of the 30th anniversary of their lunar landing, at a ceremony in NASM's "Milestones of Flight" gallery, next to the Apollo 11 command module Columbia and near the Wright Flyer. Special educational activities related to the Moon landing and other space explorations were offered to thousands of NASM visitors on that same day, as well as later during the "Geography from Space" program given as part of National Geography Awareness Week.
"Reflections on Earth," supported in part through a donation by the Honda Corporation, developed a teaching poster distributed to 40,000 middle schools nationwide in an effort to help students understand the use of space technology in the study of Earth and its environment. In addition, NASM held a teacher workshop on forest biodiversity and remote sensing, supported a variety of field studies, and developed a Web page to disseminate results from this program.
Today: A Digital View of our Dynamic Planet" is the first exhibit to display
near-real-time, global-scale Earth science data sets collected daily by
NASA, NOAA, the U.S. Navy, and the U.S. Geological Survey. The NASM program
includes daily updates to changing global views of Earth's atmosphere,
oceans, and land masses.