Science About Space

Twinkle, twinkle, magnetar...

A new class of stars was fixed in the heavens with the discovery of magnetars, super-magnetized neutron stars, that may solve three long-standing mysteries in high-energy astrophysics: What are Soft Gamma Repeaters (SGRs), neutron stars that emit random, powerful flashes of soft gamma radiation? What are Anomalous X-ray Pulsars (AXPs), neutron stars that emit X-rays like old pulsars but spin quickly like young ones? Why do so many supernova remnants have no apparent neutron stars?

Right: An artist's concept of the intense magnetic field around a magnetar. Credit: Dr. Robert Mallozzi, UAH & NASA/MSFC.

Observations of two SGRs and the discovery of the fourth known SGR allowed a team led by Dr. Chryssa Kouveliotou to confirm the once-controversial magnetar theory. Under the magnetar theory, the collapse of a star with an exceptionally strong magnetic field would leave a rapidly rotating neutron star with a magnetic field of 10¹⁴Gauss, about 1,000 times greater than "normal" neutron stars. In less than 30,000 years, the magnetar would go through SGR and AXP phases as it spins down to become invisible, leaving a supernova remnant with no apparent central body. Research teams led at SSL and using a range of instruments, including BATSE, confirmed the existence of the first two magnetars, thus opening a new branch of investigations for AXAF and other instruments.

1998 Science@NASA stories Crusty young star makes its presence felt - Gamma ray flash zaps satellites, illuminates Earth, and sheds light on several mysterious stellar events. Sept. 20, 1998. Magnetar pictures in medium and high-resolution formats. A whole lot of shakin' going on: Starquakes lead to discovery of first new Soft Gamma Repeater in 19 years. July 9, 1998. Magnetar discovery solves 19 year old mystery in astrophysics - puts the evolution of neutron stars and galaxies in a new light. May 20, 1998. The science and mysteries of magnetars, the strongest magnets in the galaxy.

From dust you came....

Dust, the smallest of cosmological bodies, is assuming greater importance as we investigate its role in the making of planets and planetoids. In 1998, SSL established the Dusty Plasmas Laboratory, directed by Dr. James Spann, to study the behavior of single grains of dust in deep space. Initial work focuses on how light electrically charges a single, smooth grain.

Right: Graduate student Cathy Venturini prepares the Dusty Plasma Laboratory for a test run. The windowed chamber at left holds the dust grain; most of the rest is the vacuum manifold that simulates the space environment. Credit: Dennis Olive, NASA/MSFC.

From this, tests will expand to understand the effects on larger, irregular grains, and how charging causes grains to clump or separate in space. Results from the Dusty Plasmas Laboratory experiments will also help in understanding what is seen in the thick dust clouds in deep space where planets are slowly condensing. Infrared telescopes can see little of what is happening because the view is obscured by the very dust that eventually will become planets, comets, asteroids, or just the dust that, as in our solar system, reflects sunlight back to give the sky a slight glow along the plane of the planets.

1998 Science@NASA stories Tiniest of space bodies to get close examination: Space dust - the building blocks of stars and planets - is the center of attention in new NASA lab. May 29, 1998.

Sunspots on the rise, and slow solar currents

The current sunspot cycle will be above the average but no record setter, according to SSL's Dr. David Hathaway, Dr. Robert M. Wilson, and Edwin J. Reichmann. They predict that Cycle 23 will rise faster than normal to its peak, attaining maximum amplitude sometime during the latter half of 1999 to the first half of 2000, and that it will measure about 170±20 units (yearly sunspot number). They expect Cycle 23 to continue until sometime in 2006 when Cycle 24, should begin. (The cycle numbers start when the Zurich numbering scheme was introduced in 1848.)

Right: A picture of Jupiter superimposed on the Sun shows the incredible size of super cells that have eluded detection for more than 20 years. These cells play a role in the movement of sunspots. Credit: NASA/MSFC.

An active sun can cause geomagnetic storms that endanger satellites and disrupt communications and power systems on Earth, and can heat the Earth's outer atmosphere so that spacecraft are exposed to more atmospheric drag and to greater erosion by atomic oxygen. Hathaway, Wilson, and Reichmann base their prediction on statistical variations in geomagnetic indices, the occurrences of high-latitude spots, the inferred strengths of the sun's polar fields, and the number of geomagnetically disturbed days in the preceding cycle.

Hathaway has also found massive circulation patterns that may play a role in moving sunspots across the face of the Sun. Like a boiling pot of water, the sun has a complex array of convection patterns that carry hot gas from the inner sun to the visible surface, where it radiates its energy, cools, and then flows back down. The existence of "super cells" flow patterns that are larger than the planet Jupiter was predicted almost 30 years ago. But the actual discovery was difficult because these cells are also the slowest, so they were easily lost in the chaos of shorter, more energetic flows. Using two years worth of data from the Solar and Heliospheric Observatory, Hathaway was able to filter out the faster flow patterns and reveal the super cells.

1998 Science@NASA stories Sunspot activity increases - As the sun approaches solar maximum, NASA scientists report that the sunspot cycle is closely following their prediction. Oct. 19, 1998. Sunspot cycle will be above average but no record setter, say NASA scientists concerning the next peak in the Sun's 11 year cycle of activity. Giant convective cells found on Sun after 30-year search, opening a new avenue for understanding the Sun and space weather.

Is anybody out there?

No single aspect of space exploration fascinates us more than the possibilities of discovering life on other worlds. While Mars has long been thought of as the best chance for life elsewhere in our solar system, recent evidence of liquid water on Europa, one of Jupiter's moons, raises the possibility of life there. In turn, the discoveries over the past few decades of life in hot springs, deep ocean vents, and even Antarctic ice broaden the range of conditions where at least basic life forms may set up housekeeping. NASA/Marshall joined this hunt in 1998 when Richard Hoover was selected as a co-investigator for two investigations funded under NASA's new Astrobiology Institute.

Right: This fragment of a microbe was found in ice brought up from deep under the surface of the Antarctic over Lake Vostok. Techniques for studying terrestrial "extremophiles" will pave the way for studies of extraterrestrial life forms. Credit: Richard Hoover, NASA/MSFC.

Hoover is a solar physicist, whose hobby studying diatoms - the "jewels of the sea" - has earned him international recognition. In one project, he will help look for biomarkers signs of life in soil and rocks, such as phosphorites from Mongolia and oil shale from Siberia. In one project, Hoover will develop methods to fix, prepare, and view samples so that unambiguous indications of life - or non-life - can be obtained. He will use advanced tools such as the Scanning Electron Microscope (ESEM) and an atomic-force microscope that NASA/Marshall uses in engineering work. In a related endeavor, Dr. David Noever won a grant to develop software that will employ hundreds of unused desktop computers linked through the Internet to sort through electron microscope images and other pictures to find promising signs of life in samples from meteorites, comets, moons, and planets.

1998 Science@NASA stories Marshall scientist to participate in Astrobiology Institute. May 22, 1998. Exotic-looking microbes turn up in ancient Antarctic ice - Exploring a microworld locked in ancient ice. July 17, 1998. Clues to possible life on Europa may lie buried in Antarctic ice. NASA and Russian scientists probe samples from above Lake Vostok. March 5, 1998.

The next Great Observatory, and more

The long-anticipated launch of the Advanced X-ray Astrophysics Facility (AXAF) is imminent. AXAF, the third of NASA's four Great Observatories for Space Astrophysics, will give astrophysicists and the public the finest, most sensitive observatory ever for studying some of the most energetic activities in the universe. AXAF's cameras and spectral instruments will be sensitive to X-rays in the 100 to 10,000 electron-volt range (0.1-10keV; by comparison, visible light is centered at about 3 eV). AXAF will have spectral and time resolutions comparable to what the Hubble Space Telescope provides in visible light, and thus will complement that observatory's discoveries.

Right: AXAF is readied for its first trip to "space" in a thermal-vacuum chamber. The mirror assembly is located in the black box at the base; the science instruments are at the top of the silver tube (the telescope barrel). Credit: TRW.

A unique Multi-Spectral Solar Telescope Array (MSSTA) developed under SSL sponsorship, was selected for a third flight. The MSSTA uses special X-ray reflecting foils to produce images of the Sun in several wavelengths at once. An SSL associate was selected to develop advanced design concepts for the Gamma-ray Large Angle Space Telescope (GLAST), the next generation instrument in gamma-ray astronomy. SSL also proposed a unique camera system, the Japanese American Solar Magnetograph Instrument (JASMIN) for flight aboard Japan's Solar B satellite in the year 2004. With JASMIN, scientists will produce highly detailed images of solar flares and magnetic fields.

1998 Science@NASA stories AXAF stories Looking for Pulsars in the Fast Lane - Scientists are looking for bizarre, short-lived, powerhouse stars that burst with some of the brightest energy in the universe. Sept. 21, 1998. Why did the supernova "morph"? Scientists using AXAF think they can discover why. Sept. 9, 1998. How hot is the Crab? NASA's next Great Observatory takes aim at the Crab Nebula pulsar. Aug. 17, 1998. Other astrophysics instruments Staring directly at the Sun: That's where the science is - A new instrument, JASMIN, may provide new views of the Sun from space and help solve heating mysteries currently puzzling scientists. Oct. 5, 1998. Solar Images to be made by unique X-ray telescope - A unique cluster of telescopes will capture multicolored images of the sun to help understand why the sun's outer atmosphere is so hot. April 2, 1998. The heavy metal hit parade of gamma rays. A powerful new instrument could point scientists to the source of mysterious, cosmological, gamma-ray bursts. Sept. 2, 1998.

Author: Dave Dooling
NASA Official: Ron Koczor

Last updated Nov. 25, 1998