Moonquakes

On earth, the shaking of the ground from an earthquke is measured by an instrument called a seismometer. Four seismometers were left on the moon after the Apollo missions in the '70s, and they radioed back through 1977. Today they help bolster the theory that the earth and the moon did not form at he same time.

When the data was first recorded, there wasn't a computer fast enough to analyze it. Researchers spread the data in long, squiggly pages and analyzed it by eye, looking for evidence of moonquakes. Recently, the data was analyzed by modern computers. Here's a summary of what they found.

There are frequent moonquakes. Certain interior parts of the moon brake repeatedly, and the rate of moonquakes suggested that they are caused by the pull of tidal forces between the moon and the earth. Almost all of the deep moonquakes originate on the side that faces earth. The moon's crust is 25 percent thinner than earlier believed.

The moon's interior has a considerably different chemical make-up than the Earth's upper mantle. This supports the idea that the moon and the earth did not form at the same time, because if that had been the case, the two bodies would be expected to have similar. Link.

Black holes bend light in strange ways

Ever notice that when you put an oar in the water, it looks like it's bent upward? Or, when you look at someone standing up to their knees in water, they look short? The physics principle behind this is refraction: light "bends", or changes direction, when it passes a boundary between two different media, like water and air. When light is bent, it it creates the illusion that an object is out of place.

Albert Einstein was first to realize that light can also be bent around stars; the intense gravity of a star can refract light. If light from a distant source passes a star, the path of the light bends, causing observers on earth to get the wrong idea about where the light came from.

Black holes have intense gravity, in fact the strongest we know of, and scientists recently determined that black holes can bend light in directions that don't jive with our understanding of normal refraction. This adds another item to the list of baffling black hole phenomenon. Link.

Puzzling Sedna

Last February, astronomers first discovered Sedna, an object a bit small than our moon, orbiting way out towards the edge of our solar system. Sedna just doesn't fit with any other object in our solar system. It's a bit too small to be called a planet, but if we don't call it a planet, we could not call Pluto a planet by the same measure. Yet, Sedna is too large and too round to be an astroid. The tilt and shape of Sedna's orbit is unlike any of the nine traditional planets, and Sedna's origin is still totally unknown. It may have formed with Earth and the traditional planets, or it may have formed somewhere else before it was captured by our sun's gravity. An article in The Washington Post explains the many mysteries of Sedna, discussing lots of good astronomy along the way. Link.

The Death Star will soon be fully operational

The Cassini Spacecraft captured this image of Saturn's moon Mimas. Mimas' huge, 138-km-wide crater makes the small moon look like the Death Star from the Star Wars films. (Mike B explains that the Death Star did not actually appear in The Empire Strikes Back, as previously reported.) Link.

Is the global climate getting warmer? Will the warming affect us? Did we cause this?

This article on global climate change is well balanced, providing facts on both sides of the issue. But, in the end, the logical conclusion is: it's going to get warmer. Link.

Star on route to exit the Milk Way

Researchers at the Harvard-Smithsonian Center for Astrophysics in Cambridge, MA have identified a star that is blazing across our galaxy at 700 km/s, a pace that will allow it to escape our galaxy.

It is believed that the star was previously a binary star, spinning with a partner star and orbiting our Milky Way galaxy. The star likely got too close to the black hole at the center of the galaxy and got swung around the center. This sling-shot effect gave the star a tremendous amount of speed, hurling the star out of its orbit and across the galaxy at a speed that is twice the necessary escape speed, the speed at which an object can break free of the galaxtic gravity. The star will travel to the edge of the galaxy, and moving to fast for gravity to stop it, it will enter intergalactic space towards, well... who knows. This is not the first time that this kind of rouge star has been observed. Link.

Meet the Vatican Astronomer

The March issue of Astronomy magazine features an interview with Father George Coyne, Jesuit priest and the Vatican's chief astronomer. Francis Reddy put some tough questions to Coyne about the perceived conflicts between religion and science.

On how his spirituality is connected to his science, Coyne says, "In a sense, they are two compartments in my life. I try to do publishable research in international journals, but then, I'm a religious priest. There is some crossover in my personal life. Knowing more about the universe, and believing that God created the universe, nourished my knowledge of the spiritual background. I believe God is creator, and I've never come to that belief through any rational process. It's not irrational -- I don't think it contradicts reason -- but it transcends reason."

Astronomy's Reddy asks Coyne, "Are you saying there are essentially no conflicts between theology and science? Could there ever be? Is there a discovery that would somehow introduce one?"

"I can't imagine a conflict between the two.", Coyne begins. "That's more a faith-based statement, but I believe God created the universe. I can't imagine that God would create a universe in which there would be some contradiction. Ignorance breeds temporary conflicts, there's no doubt about that, but that's ignorance. I would think, undoubtedly, the very distant supernova measurements that have indicated an accelerating universe is the most challenging discovery in the past couple of years."

The interview in Astronomy magazine is not available on line, but I did find a story on Coyne that ran in The Detroit News May of 2002. Link.

Who was Ernst Mayr?

Biologist Ernst Mayr died last week at the age of 100. Mayr's work was key in developing the theory of evolution. He improved upon the theory of Evolution, placing a key piece in Darwin's evolution puzzle. Darwin's famous book "Origin of Species" did not include a clear definition of the term "species". Mayr clarified the definition, explaining that a species is a group of organisms, capable of breeding among themselves, but unable to breed with others. New species can develop when an existing species splits up into two groups, and the two groups get isolated from each other, usually by geography. In time, the members of the groups will physically change to the point where they are too different to breed with members of the other group. When this happens, the groups are considered two different species. This idea is now widely accepted, and is known to biologists as allopatric speciation. Mayr is also credited as being one of the key biologists who first established the relationship between evolution with genetics. Link.

Maybe it's time to move on from the Hubble

NASA is not likely to get the $1 billion it needs to put togther a service mission for Hubble Telescope, our only space telescope. Maybe letting the Hubble Telescope die of natural causes isn't so bad after all. The project is could end up costing $2 billion. Do we want to spend that kind of money if it means less funding for other NASA programs? Do we want a risky Space Shuttle flight? I didn't realize until recently that even without he repair, the Hubble is still expected to continue to work fine for as much as another 10 years, maybe more. Meanwhile, NASA's got a fleet of new and better telescopes planned. Link.

Wicked cool science

#1 The Aurora Borealis, or Northern Lights, is a naturally-occurring colorful display in the sky. In the upper atmosphere, a layer of charged particles discharged by the Sun are attached to the Earth's north and south magnetic poles. When the particles collide with molecules of oxygen and nitrogen in the air, they make the sky glow with bright colors. Using an enormous 960-kilowatt radio transmitter, researchers at the High Frequency Active Auroral Research Program (HAARP) facility near Gakona, Alaska created shiny "speckles" of light in the Aurora Borealis. "It's cool that they created a visible effect just using radio waves," says Pat Newell, who studies the aurorae at Johns Hopkins University. Link.

#2 According to Albert Einstein's general theory of relativity, gravity bends space and time. Picture the Earth resting at the bottom of a shallow cone, created by gravity, with moon rolling around the rim: this is similar to the way Einstein described gravity. In theory, As objects move throught he universe, they send out ripples of gravity, in other words, gravity waves.

Researchers at the Laser Interferometer Gravitational Wave Observatory (LIGO) hope to enlist up to a million personal computers, linked through the web, in their search for sources of the waves, which have long been predicted by Einstein but never directly observed. A system of lasers and mirrors collects data on gravitational disturbences. (Using computers all over the web to accomplish a single large task is also being done for climate change modeling. See previous post.) The computers will attempt to match the signals to waves of different frequencies. The database is so large that it will take a million active users to make a dent. The project, known as Einstein@home, will use the computer's idle time to search particular frequencies for a 'ringing' gravity wave source. While it's at work, the program also displays a screensaver charting the location of the search in the night sky. "It's really a cool kind of project," says Bruce Allen, a physicist at the University of Wisconsin at Milwaukee. Link.

Climate change? Atmospheric scientists have no doubts about it

Earlier this week, the 200 top climate scientists, along with a few economists and politicians, assembled at Britain's Met Office, one of the world's leading providers of environmental and weather-related services. Their message: it's time for the politicians to take steps to lower emisions of carbon dioxide and other greenhouse gases. According to Stanford University's Michael Mastrandrea, "We don't really need more detail now. We already have enough information to make an educated guess on how we need to reduce emissions."

In the last 10 years, researcher have made many predictions about the effects of climate change. Larry Hughes, an environmental researcher from Dalhousie University in Halifax, Canada says that researchers agree that many of these predictions have come true, such as thermal expansion of the oceans, acidification of water, increased air temperatures, and more storm activity. "And it is apparent that things aren't getting better," says Robert Socolow, co-director of the Carbon Mitigation Initiative at Princeton University in New Jersey. "What we can tell politicians is that the list of worries is going to grow." Link.

Despite our efforts, what comes up must come down

With current technology, our ability to travel into space is trapped in a catch-22: to get more things into a spacecraft means adding more fuel, which adds more weight, which means adding more fuel. We could break the cycle if we could shield the thing that holds us down: gravity. Just think-- if you could place a box under your feet that could shield gravity, you could pretty much go anywhere you want with little effort. A gravity shield would not only revolutionive space travel, but transportation in general.

But so far, no one's been able to shield or control gravity in any way. Studies commissioned by the European Space Agency (ESA) to evaluate schemes for gravity control have concluded that, even if such control were possible, the benefits for lifting spacecraft out of the Earth's gravitational field would probably not be worth the effort. Link. In 1996, NASA began research program on "speculative propulsion methods", called Breakthrough Propulsion Physics. The program was all about finding breakthroughs in space transportation, such as rocket fuel systems that don't add mass to the spacecraft and propulsion systems that achieve incredibly high speeds. The program yielded no results, and its funding was cut in 2003. Link.

Before we can shield gravity, we need to rewrite some laws of physics. First we would have to do away with the law of conservation of energy, which says that you can create energy without using energy. For example, say you had a gravity shield, and you placed it underneath one-half of a wheel. Whay would happen? The shielded part of the wheel would rise, causing the wheel to rotate forever without a power source. The law of conservation of energy says no-can-do. The second problem is with Einstein's general theory of relativity. Used by Einstein explain gravity, the theory says that gravity results from the fact that massive objects actually bend the fabric of space itself, and you just can't undo that so easily.