Scientists want to test Galileo's remains
By Philip Pullella, Reuters | January 23, 2009


The tomb of astronomer Galileo at the Santa Croce basilica in Florence. Italian and British scientists hope to determine whether his vision problems affected his telescopic findings.

ROME - Italian and British scientists want to exhume the body of 16th-century astronomer Galileo for DNA tests to determine if his severe vision problems may have affected some of his findings.

The scientists told Reuters yesterday that DNA tests would help answer some unresolved questions about the health of the man known as the father of astronomy, whom the Vatican condemned for teaching that the Earth revolves around the sun.

"If we knew exactly what was wrong with his eyes we could use computer models to re-create what he saw in his telescope," said Paolo Galluzzi, director of the Museum of History and Science in Florence, the city where Galileo is buried.

Galileo, who lived from 1564 to 1642, is known to have had intermittent eye problems for the second half of his life and was totally blind for his last two years.

"There were periods when he saw very well and periods when he did not see very well," said Dr. Peter Watson, president of the Academia Ophthalmologica Internationalis and consultant to Addenbrooke's University Hospital, Cambridge.

Watson, who has studied Galileo's handwriting, letters, and portraits of the astronomer, suspects he may have had unilateral myopia, uveitis - an inflammation of the eye's middle layer - or a condition called creeping angle closure glaucoma.

Watson believes Galileo did not acquire eye problems by looking at the sun but by systemic illnesses, including an attack when he was young that left him temporarily deaf and caused bloody discharges and arthritis so severe he was bedridden for weeks.

He was under particular stress when he was tried for heresy by the Inquisition because the Copernican theory he supported conflicted with the Bible.

One of the "errors" that Galileo made, which Galluzzi suspects may have been attributed to his bad eyesight, is that he believed Saturn was not perfectly round but may have had an irregular, inflated side.

With his 20-power telescope and with his eyes in bad shape he might have mistaken Saturn's gaseous ring to surmise that it was formed of one planet with two moons as satellites.

"This was probably a combination of errors. He probably expected to find satellites and his eyesight may have contributed to some confusion," said Galluzzi.

Astronomers hit telescope jackpot
By Robert S. Boyd
McClatchy News Service
Published:
Friday, January 23, 2009 12:14 PM EST


Above, the team building the LSST, a large survey telescope being assembled at the Steward Observatory Mirror Lab in Tucson, Ariz., celebrates the successful casting of the telescope’s 27.5-foot-diameter mirror blank.


Holes drilled more than a mile deep in the ice at the South Pole will hold hundreds of detectors to track the course of high-energy cosmic particles streaming up from the far side of the Earth.

Astronomers this year are about to get a windfall of new and improved telescopes of unprecedented power with which to explore the universe.

The bonanza arrives 400 years after Galileo spied craters on the moon through the world’s first telescope.

Instruments coming on line in 2009 will let researchers see farther and more clearly than ever — perhaps even detect signs of life on another planet or an asteroid swooping dangerously close to Earth.

The telescopes will open new windows on the heavens by using different technologies and different wavelengths of light. They’ll be able to see things in the far ranges of ultraviolet, infrared or radio waves that are invisible in the narrow band of optical light.

“This year’s going to be huge,” said Julianne Dalcanton, an astronomer at the University of Washington in Seattle. “The new capabilities are going to be absolutely fabulous.”

The International Astronomical Union, an organization of about 10,000 professional astronomers, has named 2009 the International Year of Astronomy. That’s in honor of Galileo, who was accused of heresy by the Roman Catholic Church for insisting that the Earth moves around the sun.

“In 2009, we would like everybody on Earth to think at least once about the wonders of the universe,” said IAU President Catherine Cesarsky, a French astrophysicist.

Among telescopes projects under way in 2009 are:

u A major upgrade of the 19-year-old Hubble Space Telescope, including two advanced detectors that will vastly improve its vision for another five years.

u A bigger European rival to Hubble called the Herschel Space Observatory.

u ALMA, an array of 50-plus telescopes on a lofty desert in Chile that will be the most powerful ground-based observation system to date.

u Kepler, an orbiting telescope designed specifically to look for inhabitable planets around distant stars.

u Pan-STARRS, a set of four interconnected telescopes to detect fast-moving hazardous objects, such as satellites or space rocks.

u IceCube, an upside-down space particle observatory buried under the ice at the South Pole.

u The Allen Telescope Array, a set of 42 of radio telescopes listening for extra-terrestrial messages from possible civilizations around another star.

Waiting for future financing are even larger, more powerful machines, including two giant telescopes with light-collecting mirrors three to four times bigger than any existing telescope.

The larger of the two, the 140-foot-wide European Extremely Large Telescope, could make pictures of clouds, mountains and seas on distant planets. It’s now in the design stage, and construction might begin in 2010. Despite its huge size, it’s a scaled-down version of a 330-foot Overwhelmingly Large (OWL) telescope that was canceled for technical and cost reasons.

Another ground-based instrument, the Large Synoptic Survey Telescope (LSST) will take about 1,000 images of each spot in the entire sky over its lifetime. Taken together, the repeated images will produce color movies of celestial objects as they change or move, including potentially hazardous asteroids. The LSST can also trace changes in the expansion of the universe caused by the mysterious force known as dark energy. Work on the telescope mirror is under way, and it should start taking images in 2015.

The James Webb Space Telescope, NASA’s successor to Hubble, is under construction and scheduled for launch in 2013. Its main mirror, 21 feet in diameter, has to be folded up to fit in the launch vehicle, along with a sunshield that opens up to the size of a tennis court. JWST will orbit almost a million miles from Earth, where it will study the first stars and galaxies formed after the birth of the universe, 13.7 billion years ago. Unlike Hubble, JWST mostly will work in infrared light.

Here are main features of the new crop of telescopes:

Hubble

The Hubble Space Telescope, which was launched in 1990, will get a new lease on life when NASA launches the fifth and final shuttle mission to repair and upgrade its aging instruments. The launch is scheduled for May 12.

In addition, astronauts will install two devices — a Wide Field Camera and a Cosmic Origins Spectrograph — that will add fresh capabilities to the venerable Hubble.

“We estimate that at the end of this repair, Hubble will be 90 times more powerful than when it was first launched,” said Sandra Faber, an astronomer at the University of California, Santa Cruz.

Dalcanton, the University of Washington astronomer, is especially excited by the new spectrograph, a device that can determine the chemical makeup of a star and the atmosphere of an alien planet. This information is usually more valuable to scientists than a pretty image.

“An image tells us something’s there,” Dalcanton said. “Spectra tell us what kind of object it is, what it’s made of, and does it have an atmosphere.”

Herschel

On April 10, the European Space Agency is scheduled to launch the Herschel Space Observatory — a telescope that’s bigger and more powerful than Hubble is. Herschel’s main light-collecting mirror is 11.5 feet wide, one and a half times bigger than Hubble’s, and the largest mirror ever deployed in space.

Herschel will be parked 900,000 miles out in space, far beyond Hubble’s 350-mile, low-earth orbit, and will observe mostly in the far-infrared range, which Hubble doesn’t reach.

Piggybacking on the same launch rocket with Herschel will be the Planck Satellite, a European telescope that will survey the cosmic background radiation left over from the birth of the universe in greater detail than ever before.

Alma

Work is proceeding rapidly on the Atacama Large Millimeter Array — ALMA for short — an assembly of 66 huge antennas on the 16,500-foot-elevation Atacama desert in Chile. It’s one of the coldest, driest places on Earth, which minimizes atmospheric interference.

The first of its 100-ton antennas will be delivered to the site a year from now. Linked together by computers, they’ll collect radiation from objects in the coldest, deepest regions of space with 10 times the resolution of Hubble. ALMA may be able to observe the formation of planets around other stars.

Allen telescope

This array of 42 radio antennas near Mount Lassen in northern California will begin in March collecting extremely faint radio signals from space. Its sponsors hope to make the first detection of intelligent life beyond the solar system.

The search will concentrate on about 250,000 “promising target stars” near the center of the Milky Way galaxy, said Jill Tarter, director of the Center for SETI (Search for Extra-Terrestrial Intelligence) Research in Mountain View, Calif. Tarter, who’s the real-life basis for the Jodie Foster character in the movie “Contact,” has devoted her career to searching for alien civilizations.

“At first we will give highest priority to target stars that are known to host exo-planetary systems,” Tarter said. If more funds are found, the Allen array will be expanded to 350 antennas, hoping to catch a call from ET.

Kepler

The Kepler telescope, NASA’s alien planet hunter, is scheduled for launch on March 5 into an orbit that will trail behind the Earth as it circles the sun. It will spend three and a half years precisely measuring the brightness of 100,000 stars in the Milky Way.

Kepler will be looking for a slight dimming of a star’s light — evidence that a planet is crossing in front of it. The change in brightness will let scientists determine the size and orbit of the planet, which will show whether it might be able to support life. It’s the first mission specifically designed to detect Earth-like planets.

Icecube

This unusual telescope is nearing completion under the ice at the South Pole. Instead of looking up to the sky, IceCube looks down through Earth to detect high-energy cosmic particles called neutrinos, which are produced by exotic objects, such as black holes or galactic explosions, in deep space. Neutrinos are extremely hard to detect because they travel at almost the speed of light and can zip untouched through ordinary matter.

When finished in 2011, IceCube will consist of 70 long “strings,” each holding 60 light detectors, sunk in holes drilled a mile or more into the clear ice. The detectors will track neutrinos that have passed through the planet so scientists can determine their origin.

So far, 52 detector strings have been installed. Researchers began collecting data in April 2008.

A sensational, if unlikely, IceCube result would be the first strong evidence that the world contains extra dimensions — beyond the four familiar dimensions of space and time. Extra dimensions are a key part of “string theory,” currently the most fashionable version of the physical laws that govern the universe.

Astronomers try to solve mystery of bulging stars


In a new study, researchers present 3-D simulations of the formation of massive stars. This snapshot from the simulation shows a polar view of a star 55,000 years into its evolution.


Obesity has apparently reached galactic proportions, apparently — even stars have a problem with over-eating, a stellar mystery that has astronomers asking how some stars grow to be so large. A supercomputer scientist team may have the answer, in a demonstration of how nature can take something simple and make it complex.
About 7,500 light years away resides the star Eta Carinae, first noted in a star catalogue by the venerable astronomer Edmond Halley (best known for Halley's comet) in 1677. Since then, the star has bedazzled astronomers by brightening every century or so, most notably in an 1843 outburst that briefly made it the brightest star in the sky, despite its distance (one light year is about 5.9 trillion miles.) To add to the mystery, the star is a porker, about 120 times heavier than the sun, embedded in a star-forming gas cloud called the Carina Nebula.

University of California, Berkeley, astronomer Nathan Smith proposed last year in the journal Nature that 1843 outburst arose from an explosion deep in the star that spat out a blob of star-stuff perhaps ten times as heavy as the sun. The report counts the explosion as a newly-discovered mechanism for how gigantic stars, which only live a million years or so, start to break down prior to their final implosion (the process that forms black holes.)

But that left the bigger mystery, which is how do stars like Eta Carinae get so big in the first place? "We see stars at least 120 times that of the Sun throughout space, but the mechanism by which the most massive stars form is a longstanding mystery," says astronomer Mark Krumholz of the University of California, Santa Cruz. Astronomers know that stars form by the clumping together of gas clouds. These "proto-stars" ignite through nuclear fusion once they become about 80 times heavier than the planet Jupiter.

Stars are thereafter balancing acts, Krumholz explains, in which the inward pull of gravity from the center of a star fights against the outward "radiation pressure" from light and other electromagnetic radiation emitted by its nuclear furnace. Where the push and pull of the two forces balance out, you have the surface of the star.

For astronomers, all this works out nicely to produce young stars up to about 20 times heavier than the sun. But once the star grows larger, the math stops working and the radiation force pressure overwhelms the gravitational urge to pull in gas from outside the star. "But still, we see them, so they must grow somehow," Krumholz says.

So, to crack the mystery, he and his colleagues decided to grow their own super-massive star. Inside a rented super-computer, they programmed the simplest start for one, a circular cloud of gas about 100 times the weight of the sun. In the three-dimensional simulation, a first, the cloud collapsed into a circular disk and sparked a young star, which "grew" to 11 times the weight of the sun in 20,000 simulated years, just as theory predicted. Past that point, things starting getting interesting. First the disc surrounding the star grew spiral arms that helped shovel gas into its maw for another 6,000 years, until it grew to 17 times heftier than our sun.

At that point, the radiation pressure from the star began to out-battle the force of gravity. But instead of pushing the disc gas away evenly, the radiation pressure blew out powerful "bubbles" along the axes of the star. "Almost all gas falling onto the protostar struck the walls of the bubbles, where it was shocked and swept up into the bubble walls. However, this did not slow accretion in our simulation, because the gas that struck the bubble walls eventually traveled along the margin until it reached the disk, at which point it continued to accrete onto the star," reports the study released by the journal Science. "The trick is to look at the star in three dimensions where you see these bubbles develop," Krumholz says.

Avoiding any jokes about Alka-Seltzer, Krumholz and colleagues find the bubbles give the radiation pressure a way to escape, while letting the star continue to gobble up more star-forming stuff. Interestingly, a second stars started to form in the gas disk as the process becomes more unbalanced with the strengthening of the radiation bubbles. Why massive stars always have companions was another mystery, one the simulation thereby also cleared up, a two-fer for astronomy. (A third star actually formed in the simulation, but that unfortunate orb fell back into its parent star.)

After about 57,000 years of simulated time, the researchers halted the star's growth, finding it had quite burgeoned to about 70 times the mass of the sun. "It ran for 40 days and 40 nights, when you add it up," of expensive supercomputer time, Krumholz says.

So that mystery solved, the question of why super-massive stars top off at about 120 times the weight of the sun remains. "The size of a star in our simulation is only limited by the size of the starting gas cloud," Krumholz says. He and others suspect some still-undiscovered mechanism starts knocking out interior explosions of star stuff, like those seen from Eta Carinae, once they reach the most overstuffed sizes, Krumholz says. "You can lose mass in a hurry by spitting out 10-solar-mass eruptions, after all."