UPDATE: NEWSREPORTS
Black Holes
Update 1/14/97:
Every galaxy has a black hole in it.
New evidence has convinced astronomers that a massive black hole exist at the center of almost every galaxy, including our own Milky Way, gobbling up stars that will never be seen again. Two teams of astronomers reported their findings about the surprising frequency of these objects - first predicted by Einstein's Theory of Relativity - at a conference of the American Astronomy Society in Toronto yesterday.
Although black holes cannot be seen, they can be detected by the violent movement of nearby stars that are about to be swallowed by one of these "cosmic vacuum cleaners", according to Ramesh Narayan of the Harvard-Smithsonian Center for Astrophysics in Cambridge, MA.
Narayan called the process "the ultimate victory of gravity... What's inside is completely cut off from the rest of the universe."
Luckily, Earth is in no danger of falling into a black hole. The nearest such monster in our galaxy, the one at the center of the Milky Way, is 30,000 light years away. Despite its incredible power, a black hole makes up only a tiny fraction of the material in its galaxy, less than 1 percent. "The vast bulk of the galaxy is not affected by the black hole in the center," said Scott Tremaine of the Canadian Institute of Theoretical Astrophysics.
Using different techniques, the two teams of astronomers found two distinct types of black holes. One group of 12 astronomers, headed by Douglas Richstone of the University of Michigan, surveyed 15 nearby galaxies using the Hubble Space Telescope and the 36-foot Keck telescope on top of a volcano in Hawaii. They announced the discovery of three massive black holes and strong evidence for a dozen others within 50 million light years of Earth. Richstone said the "celestial fingerprint" consists of a unique pattern in the velocity of stars spinning around the center of each galaxy, indicating that they are being sucked in by a powerful, invisible object. The holes may be the remnants of burned-out quasars, the oldest and most energetic objects in the early universe. "Black holes are dead quasars", Richstone said.
The second astronomical team, headed by Narayan, the harvard astrophysicist, observed another, smaller type of black hole created by a pair of stars revolving about each other. One of the stars in such a system is constantly pulling gas off its partner. The gas becomes tremendously hot - up to a trillion degrees - and radiates X-rays, producing what is known as an X-ray Nova.
If the star is less than 40 times as massive as the sun, it eventually burns to a crisp and becomes a so-called neutron star. "If it is more than 40 times as massive as the sun, Narayan said, it apparently forms a black hole." The Harvard-Smithsonian team studied nine X-ray Novae and found five with neutron stars and four likely black holes. One such star in the constellation Cygnus, 10,000 light years away, "seems to be swallowing nearly a hundred times as much energy as it radiates", said Narayan. "The energy disappears into the black hole, never to be seen again. The only way this can happen is if the star is a true black hole. This is the most direct evidence scientists have had that black holes are real." - End newsreport -
Life of the Universe
Update 1/16/97:
The Universe will live longer than expected
At the meeting in Toronto of the American Astronomical Society (see the 1/14/97 newsreport), two astrophysics, Fred Adams and Gregory Laughlin of the University of Michigan, presented a new study entitled "The Long Term Fate and Evolution of The Universe" which explains a four-step analysis of the subject.
The first phase covers the next 100 trillion years which they call the "stelliferous era", (that is the current timeperiod) in which stars are the most important component of the cosmos. But stars eventually die off, and the time will come, they explain, when there will be no more stars left in all the vastness of space (Phase two).
At that point the only things left will be black holes, white dwarfs and neutron stars. There might be some brown dwarfs around as well, lukewarm objects that were too small to become stars, but several of them might collide and form stars. However, the universe will then be very dark and a lonely place, and will stay that way until about 10 trillion trillion trillion years from now (talking about infinity?, then things will get worse (Phase three). There will be nothing left but black holes, very far apart from each other in the extremely cold and dark emptiness. This phase 3, the "black hole era", will persist, they say, until about 10,000 trillion trillion trillion trillion trillion trillion trillion years from now. (that's a 1 with 100 zeros after it - that's what safely could be called eternity).
Even black holes don't last forever, though, as physicist and best selling author Stephen Hawking discovered some years ago. Black holes radiate away energy over time, Hawking found. The black holes gradually lose mass and finally evaporate. What's left in phase four when all the black holes are gone? Just four kinds of subatomic particles, electrons, positrons, neutrinos and photons - back to the basic building blocks or elementary particles. We live in an expanding universe at the moment and according to some theories, the rate of expansion may even be accelerating. Thus, the very few remaining particles are very, very far away from their nearest neighbors. This phase four, called "the dark era", will go on forever, say Adams and Laughlin.
The universe will be cold, dark, lonely and featureless. This scenario shows that one of the major factors that determine what happens to the universe is the decay of fundamental particles called protons. When protons decay, that's the end of matter, so when they have all decayed, there can be no more stars, planets or people (this is in the beginning of phase three). Experiments have determined that protons last more than 10 million trillion trillion years, but we don't know how much longer. If this theory will prevail, the good news is that our time in the universe will be much, much longer than we anticipated before. Adams and Laughlin will present their paper, "A Dying Universe", in a forthcoming issue of "Reviews of Modern Physics".
- End newsreport -
NASA keep an eye on an asteroid
Update 1/31/97:
NASA scientists said yesterday that they have detected an asteroid which crosses Earth's orbit every 9 1/2 months and that they plan to study its potential for a collision.
Jet Propulsion Laboratory experts using an electronic telescope at an Air Force installation on Mount Haleakala, Hawaii, picked up the asteroid Jan 10, and astronomers around the world have observed it since then, JPL said. The object, dubbed 1997 AC11, is a member of a rare class of asteroids called Atens, which stay within Earth's orbit most of their lifetimes, said Eleanor Helin, principal investigator of the project.
NASA's New Exciting Mission for the Hubble Telescope
Update 2/1/97:
NASA is preparing a new spectacular mission for the Hubble Telescope later this month. Even more powerful cameras will be installed so that the telescope will be able to see 95% of the way to the edge of the universe. Astronauts will spend 25 hours over four days walking in space to make the installation and the total is a ten days mission. The project is overseen by Edward Weiler, Hubble's chief scientist. He says: "The dramatic increase in science is well worth the risk (to mess with the telescope). It will open a new window on the universe."
One of the new devices is a set of infrared cameras that will enable scientists to study extremely remote objects that are invisible in ordinary light. In effect, the new camera will double the range of the electromagnetic spectrum open to astronomers. The existing telescope can see back 6 to 7 billion years, to when the universe was about one-third its present age and size. The new cameras will be able to look back about 10 billion years, within a billion or so years of the big bang that scientists believe marked the beginning of space and time. "It will let us explore lands we've never seen before" said project scientist David Leckrone of NASA's Goddard Space Flight Center.
Another instrument is an advanced spectrograph that can break down the light from distant stars and galaxies and reveal their chemical composition, temperature and motion. The spectrograph can hunt for the mysterious black holes that are believed to lurk at the center of most galaxies, swallowing anything, even light , that gets too close. Other equipment will be replaced. During the 11-day , $347 million mission aboard the space shuttle Discovery, the astronauts will also try to boost the telescope into a five-mile-higher orbit. The launch is scheduled for 2:56 a.m. Tuesday Feb 11 from Cape Canaveral.
Discover Shuttle on it's way to the Hubble Telescope with new equipment
Update 2/11/97:
After some delays, the Discover Space Shuttle basted off today without any problems at about 4 am EST. Once in orbit, the seven astronauts began steering the shuttle toward a rendezvous planned for early Thursday 2/13/97 with the 24,000-pound Hubble telescope, 362 miles above Earth. "We are replacing 1970s technology with 1990s technology to greatly expand Hubble's discovery capability", said Dr. Edward Weiler, the project's chief scientist for NASA. Two refrigerator-size spectographs will be removed and replaced by a new imaging spectrograph and an infrared camera, each giving the 94.5-inch telescope deeper and more revealing views of the universe.
The Space Telescope Imaging Spectrograph (STIS), for example, is an instrument that separates light gathered by the telescope into its component colors. Observation with it are expected to reveal the chemical composition of celestial objects and show how their composition changed as the universe evolved. They can also tell astronomers the temperatures, densities and motions of distant objects. Dr. Bruce Woodgate of the Goddard Space Flight Center in Greenbelt, Md., said the instrument was expected to detect new and even more distant galaxies and be "a more powerful black-hole hunter". With greater power and sensitivity, Woodgate said, the new spectrograph should be able to measure more precisely the whirlpools of matter at the cores of galaxies and thus reveal the presence of black holes that gobble up everything around.
The other new piece of equipment, the Near Infrared Camera and Multiobject Spectrometer (NICMOS), should expand the Hubble telescope's vision to different wave lengths, enabling scientists to examine even fainter and more distant phenomena in the universe. By looking deep into space with its supercooled infrared heat-sensitive eyes, the telescope should get a better view of the birth of stars and galaxies forming when the universe was only one-tenth its present age, and perhaps detect planets around distant stars. Thus, scientists will be able to see to near the end of the universe and near the beginning of time. You may keep yourself posted by accessing NASA's web-sites on the Universe page or this update page.
Planning for The Next Generation Space Telescope (NGST)
Update 2/12/97:
The Hubble telescope is scheduled to end operations in 2005 as it technically and astronomically is on its way to becoming something of a has-been. Its successor, the Next Generation Space Telescope (NGST), is being designed to view back to the time when the first galaxies and stars began evolving. "We're managing to keep Hubble upgraded with new technology, both in instruments and in a lot of support systems", said Maureen Locke, at NASA's Goddard Space Flight Center in Greenbelt, MD. "But there is going to be a limited lifetime. You need to start planning now for the time when Hubble will no longer be state-of the-art technology, or no longer functional."
Last year, NASA funded separate industry studies of how best to build NGST, and initiated its own design study. "NGST will provide quite a leap in capability and will be significantly more capable than anything we will ever be able to build on the ground", said Michael Kaplan, a NASA executive who works on large space telescopes.
For NGST, the space agency envisions a large-aperture space telescope, housing a mirror 20 feet to 26 feet in diameter, that would be one-fifth the mass of the Hubble's 7-foot diameter mirror. Compared with existing or planned ground- or space-based telescopes, NGST would be up to 1,000 times more sensitive and would carry sensing detectors in the visible and near-infrared parts of the electromagnetic spectrum. To view the faint light from faraway galaxies, NGST would be placed far away from the Earth-moon system, perhaps at a location 40,000 miles beyond the Earth's moon known as the Lagrange point (L2). Positioning it here would reduce stray light and keep the telescope extremely cold. Because of the gravitational forces of Earth and moon at that point, the telescope would remain locked in place. Kaplan said NGST's price tag is gauged to avoid public and political sticker shock: Building costs are expected to be in the $500 million range, with an additional $45 million a year for 10 years in operation costs. hubble, by comparison, cost roughly $2 billion to build, and some $250 million a year to operate.
Not an off-the-shelf venture, NGST will demand a suite of advanced technologies, Kaplan said, including large and ultra-light-weight mirrors; deployable and inflatable structures; high-precision pointing and vibration-dampening devices; and autonomous control hardware. "Another issue", he said, "is to convince the scientific community that we can actually pull this off, given the challenges and for the cost".
Last year, NASA provided money to two California aerospace firms, asking each to design a Next Generation Space Telescope. Lockheed Martin of Sunnyvale and TRW Space & Electronics Group in Redondo Beach set up NGST study teams. So did a group from NASA's Goddard Space Flight Center, which is managing the overall NGST effort and coming up with its own design.
Thoughout 1997, NASA plans to further evaluate NGST, defining the technical and cost challenges for building the space observatory. Current schedules suggest that NGST could be built and launched by 2007. So far, "probably the most revolutionary answer that has come back was that it seems possible to buld the NGST for the cost we are considering," said John Mather, a NGST study scientist at NASA Goddard.
Soon, on this page, we will briefly describe some of the initial designs to be submitted by TRW and Lockheed Martin.
Proposed NGST design (preliminary)
Update 2/13/97:
See yesterday's report on NGST
TRW's concept includes a 26-foot-diameter mirror made from six petals that unfold once in space. Mirror petals deploy from a stacked position, a package that can be neatly tucked inside a 10-foot-diameter rocket shroud. A large shade on the telescope would block the sun's warming rays and keep the instrument ultra-cold. The idea is based on a once-classified TRW program named High Accuracy Reflector Development (HARD), said Charles Lillie, NGST study manager for the firm. The deployable-mirror design can be expanded to obtain even larger apertures, up to 65 feet in diameter, he said.
NASA's design, similar to the TRW approach, is tightly packaged to ride aboard an Atlas rocket. It deploys a set of eight petals that adjust to form a 26-foot mirror. A large , inflatable sun shield is attached to the telescope, helping to cool it.
Lockheed Martin's NGST design ideas appear to stem from jobs crafting military spy satellites and intelligence-gathering spacecraft. One Lockheed Martin proposal includes a one-piece primary mirror nearly 20 feet in diameter. Once in space, the mirror's thin reflecting surface would be conformed into perfect shape by 2,000 actuators mounted on the backside of the mirror. This design could be hurled spaceward atop a Russian Proton booster.
"The fundamental idea is pretty clear. Build something thin and adjust it in space," said John Mather, a NGST study scientist at NASA Goddard. "We have considerable reason for being optimistic that this can be done." Early tests of NGST hardware - including equipment that inflates or unfurls, and precision-alignment mechanisms - are likely to fly on space-shuttle missions in the near-future, he said.
NGST is part of a NASA pursuit called Quest for Origins, which seeks to trace the 15 billion-year chain of events that followed the "big bang". Even with its new instruments, the Hubble telescope will be limited to viewing "adolescent" objects - galaxies that formed perhaps 5 billion years ago, NASA's Michael Kaplan said, a NASA executive who works on large space telescopes. Other spacecraft, specifically the Cosmic Background Explorer (COBE), have gone further back in time, detecting the seeds of galaxies and other large-scale structures evolving 300,000 years after the big bang. NGST will provide information on the time in between - when the universe was roughly between 1 million and a few billion years old, and the first stars and galaxies began to form.
"NGST will plug in a gap, a missing era in which galaxies started to form as we see them in the present-day universe," Kaplan said. "We know that with NGST, a probe in this part of space time can be made. What we don't know are all the other amazing things NGST will be capable of doing. We are likely to be blown away by the things that we discover and see." NGST could provide useful information for another goal - detecting Earth-like planets orbiting other stars, said Bernard Seery, NGST study-team manager at Goddard Space Flight Center. Such detection would require deployable or inflatable telescopes many times larger than that planned for NGST. Nonetheless, Seery said, NGST would be a step forward that goal, opening wider a window on the universe at large.
It's time to seek life on Mars, scientists says
Update 2/15/97:
A UCSD (San Diego) planetary scientist is advocating a pinpoint mission to Mars to answer questions about life there - and relatively quickly, by 2010. He says popular interest is high and the political climate is right. John Kerrige is arguing for a carefully orchestrated mission that would survey sites where fossilized microbes most likely would exist. "The only way to do that is a robotic mission that would collect samples from carefully selected locations and bring them back," Kerrige said.
Speaking at the annual meeting of the American Association for the Advancement of Science in Seattle yesterday, he said meteorites from Mars that have landed on Earth that have landed on Earth are too random and chemically altered to provide answers and spacecraft on their way to Mars are not equipped to answer the question either.
Kerrige advocates a mission that would involve separate launches to Mars; an orbiting surveyor to map the surface, revealing chemical details of the rocks, followed by a rover vehicle that would analyze many sites before a robotic craft landed to dig up the best samples. The Mars Pathfinder, which is scheduled to land on the planet in July, will do other types of experiments on the surface, including releasing a rover. Collecting samples without first conducting a rigorous search for the best sites would lessen the chance of finding evidence of life, he said.
Is the Universe larger than we thought?
Update 2/17/97:
The European Space Agency's Hipparcos satellite, launched in 1989, has mesured the position of 120,000 stars, and the results have led scientists to correct one of their basic measuring sticks of the universe, it was explained recently during a meeting of the Royal Astronomical Society in London.
The Hipparcos measurements of pulsing stars called "cepheids" indicated they are about 10 percent farther away than previously estimated. That means that the universe is bigger and perhaps a billion years older than previously thought. The Hipparcos conclusions may help resolve a paradox that has emerged from other ways of measuring: that the universe is younger than the oldest stars. "Until Hipparcos, the cosmic distance scale rested on well-informed guesses. The distance we now have, for stars of many kinds, provide for the first time a firm foundation from which to gauge the distances of galaxies," said Michael Perryman, project scientist for the European Space Agency. Cepheids are an important benchmark for stellar measurements because their brightness is directly related to their pulse - the longer the pulse, the brighter the star. By comparing the brightnesss of two cepheids with the same pulse, astronomers can estimate how far apart they are. The Hipparcos measurements indicate the oldest stars are about 11 billion years old, while the universe is somewhere between 10 billion and 13 billion years old. Other estimates have the stars up to 14 billion years old and the universe as young as 9 billion years. "I hope we've cured a nonsensical contradiction that was a headache for cosmologist", said Michael Feast of the University of Cape Town in South Africa. "We judge the universe to be a little bigger and therefore a little older, by about a billion years."
Robert Kirshner, professor of astronomy at Harvard University, said the key will be nailing down where in the 10 billion to 13 billion year range the universe's age falls. "If their number is 10 to 13 billion, it isn't settled but we are finally getting to the point where we don't disagree on the distance scale by a factor of two, but by 10 percent. That's good. It means science is growing up," Kirshner said. "Measurement is one of the most fundamental parameters of astronomy and one of the weakest before the Hipparcos mission," said Floor van Leeuwen of the Royal Greenwich Observatory. Full data on the results will be published in June.
Dinosaurs' extinction - asteroid is found to be the "smoking gun"
Update 2/17/97:
Scientists who drilled core samples from the ocean bed said yesterday they have found proof that a huge asteroid smashed into the Earth 65 million years ago and probably killed off the dinosaurs. "We've got the smoking gun," said Richard Norris, leader of an international ocean drilling expedition that probed the Altantic floor in search of asteroid evidence. Norris said the expedition recovered three drill samples that have the unmistakably signature of an asteroid impact about 65 million years ago. The drill cores include a thin brownish section that the scientists called the "fireball layer" because it is thought to contain bits of the asteroid itself. "These neat layers of sediment bracketing the impacts have never been found in the sea before," Norris said. The scientists were working on the drill ship JOIDES Resolution during 5 weeks off the east coast of Florida collecting cores from the ocean floor in about 8,500 feet of water. The team penetrated 300 feet beneath the sea bed.
Although the dinosaur-killing impact is thought to have occurred in the southern Gulf of Mexico, Norris and his team went to the Atlantic Ocean, near the dge of the continental shelf. He said the violence of the impact, followed by huge waves, roiled the Gulf of Mexico so much that it is unlikely clear core samples could be found there. He said he theorized that waves from the impact would have washed completely across Florida, depositing debris in the Atlantic. And that's where he found it. Robert Corell, assistant director for geosciences of the National Science Foundation, said the core samples are the strongest evidence yet that an asteroid impact caused the extinction. "In my view, this is the most significant discovery in geosciences in 20 years," he said.
Geologist Walter Alvarez of UC Berkeley first proposed in 1980 that the dinosaurs disappeared from fossil history suddenly because of a massive asteroid strike. At first, the theory had few supporters. But in 1989, scientists found evidence of a huge impact crater north of Chicxulub on Mexico's Yucatan Peninsula. Later studies found evidence of debris washed out of the gulf by waves that went inland as far as what is now Arkansas. It is now widely thought that an asteroid of 6 to 12 miles in diameter smashed to Earth at thousands of miles an hour, It instantly gouged a crater 150 to 180 miles wide. "That energy release was more powerful than if all of the nuclear weapons ever made were set off at one," Norris said.
Billions of tons of soil , sulphur and rock vapor were lifted into the atmosphere, blotting out the sun. Temperatures around the globe plunged. Up to 70 percent of all species, including the dinosaurs, perished. Among the survivors, some scientists think, were small mammals that, over millions of years, evolved into many new species, including humans.
Discovery Landing - mission completed
Update 2/21/97:
Discovery's astronauts made a rare, nighttime shuttle landing in Florida at about 3:30 a.m. today, marking the successful completion of their mission to restore the Hubble Space Telescope. The seven astronauts left the Hubble with sharper eyes, a better brain and balance, and extra thermal skin. A record-tying fifth spacewalk was required to patch peeling insulation on the telescope. The crew also boosted Hubble into a 385 mile high orbit during the 10-day mission, the highest the telescope - or a space shuttle - has ever flown.
Humans in Siberia 300,000 years ago - much earlier than previously thought
Update 2/28/97:
Primitive humans thrived in the killing cold of northern Siberia 300,000 years ago, much sooner than once believed possible, according to new age-dating of stone tools dug from frozen tundra. "Prior to this, the oldest known occupants of Siberia were about 30,000 years ago. Before this, it was though that only (anatomically) modern humans could have lived there. It shows us that people even in that early time had the skills to deal with the severe cold," said Michael Waters of Texas A&M University, head of a field expedition to Siberia. The study will be published today in the journal Science. The study was made at a place named Diring Yuriakh located on a plateau above the Lena River, near the town of Yakutsk and just about 300 miles south of the Arctic Circle. The weather in Siberia 300,000 years ago is thought to have been very much like the weather there now. Winter temperatures at Diring Yuriakh routinely drop to minus 70 degrees and the soil freezes down to about 3 feet.
Other scientists reported this week the discovery in Germany of some 400,000-year-old spears and evidence of a skilled hunting culture. Waters said these findings are a surprise because most researchers had thought sophisticated survival skills came into wide use among ancient humanlike animals only with the appearance about 150,000 years ago of anatomically modern humans.
Water discovered on Jupiter's moon Europa
Update 4/10/97:
Yesterday, NASA scientists announced the discovery of an extraterrestrial ocean buried beneath the frozen surface of Europa, one of the moons of Jupiter. Water is the key ingredient for life as we know it. While the NASA scientists don't have proof, they say life stands a good chance of existing on this moon. If so, they are fairly sure another mission would find it.
Evidence for the ocean came from finely detailed pictures of Europa's alien landscape just beamed back from Galileo spacecraft. These pictures revealed a jumble of "icebergs" and flat-topped blocks of ice that appeared to have twisted and turned from the motion of an underlying liquid or a muddy slush. As far as water is concerned, "it looks as though we've found the smoking gun," said planetary scientist Michael Carr of the U.S. Geological Survey.
"This is the first ocean discovered since the one Balboa discovered (the Pacific) five centuries ago," noted planetary scientist Richard Terrile of NASA's Jet Propulsion Laboratory (JPL) in Pasadena, speaking at a news conference held there. "There may be more water on Europa than on all the oceans of the Earth", a lot considering that Europa is about the size of the Earth's moon. Though the researchers haven't detected anything swimming yet, "the main ingredients are there," said geologist Ronald Greeley from the University of Arizona. Those ingredients, he said, are water, a source of heat, and organic chemicals such as hydrocarbons, alcohols, sugars and amino acids. "Put those ingredients together on Earth and you get life within a billion years," said NASA scientist Terrile
Sodium gas trail discovered behind the Hale-Bopp comet
Update 4/20/97:
Astronomers say the have found a third tail trailing behind the Hale-Bopp comet - a thin straight jet of sodium gas unlike any other seen before, The Boston Globe reported yesterday. The discovery was made Friday by a team of astronomers at the Isaac Newton Group of telescopes in the Canary Islands. The scientists were at a loss to explain how the sodium tail was created. The astronomers used a filter over a telescope that allowed them to detect the light given off by sodium gas, the same yellow glow seen in ordinary sodium-vapor street lamps. Astronomers have long known that comets have two types of tails - one made of dust and the other of electrically charged gas called plasma. They have also known that comets contain sodium, but had never seen it before in the form of a tail.