Mystery impact leaves Earth-size mark on Jupiter

An amateur astronomer in Australia noticed the new mark -- seen through telescopes as a dark spot -- on the planet early Monday and tipped off scientists at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California, who then confirmed it was the result of a new impact, NASA said.

It's not clear what the object was that crashed into Jupiter's poisonous atmosphere.

Glenn Orton, a JPL scientist, told the magazine New Scientist that it could have been a block of ice from somewhere in Jupiter's neighborhood, or a wandering comet that was too faint for astronomers to have detected before impact.

The object created a mark on Jupiter that has the about same diameter as Earth, though the object itself was probably only 50 to 100 miles across, said Anthony Wesley, the amateur astronomer who first noticed the scar.

The mystery object was likely moving at speeds of about 50 to 100 kilometers (31 to 62 miles) per second when it struck near Jupiter's south pole, Wesley told CNN.

"That generates an unbelievable amount of energy when it collides with pretty much anything, but especially with something the size of Jupiter," he said.

It is only the second time scientists have been able to observe the results of such an impact on Jupiter. The first happened 15 years ago, when comet Shoemaker-Levy 9 broke into 21 pieces and hit the planet's atmosphere.

"Given the rarity of these events, it's extremely exciting to be involved in these observations," JPL astronomer Leigh Fletcher said in a NASA interview.

Thermal images taken by NASA show the scar as a bright spot, which means the crash warmed the lower atmosphere in that area, New Scientist said.

Researchers also found hints of higher-than-normal amounts of ammonia in the upper atmosphere. The Shoemaker-Levy comet also churned up extra ammonia, the magazine said.

Jupiter's new spot isn't likely to last long -- probably just one to two weeks, Wesley said. He pointed out the impact scars from the Shoemaker-Levy debris lasted only two to three weeks before disappearing.

Seeing an Earth-sized spot appear so tiny on Jupiter's surface led to some to wonder Tuesday whether our planet might be in danger of a similar collision.

But Wesley said that shouldn't be a concern because Jupiter functions almost like a celestial vacuum cleaner, sucking up any objects that would be of danger to Earth and its neighbors.

"Jupiter is doing a very good job in scooping up a lot of this material that's still floating around in the solar system," he said.

"It's just got so much gravity as it swings around the outer part of the solar system, it can really pull in and swallow up many of the cometary objects and debris left over from the formation of the solar system.

"So it's doing a good job in keeping us safe by cleaning out a lot of these bits and pieces."

Jupiter is the fifth planet from the sun and the largest in our solar system.

Its colorful atmosphere is 86 percent hydrogen and 14 percent helium, with tiny amounts of methane, ammonia, phosphine, water, acetylene, ethane, germanium, and carbon monoxide. The chemicals are responsible for producing the different colors of Jupiter's clouds.

The temperature at the top of those clouds is about 230 degrees below zero Fahrenheit (145 degrees below zero Celsius), but it is far hotter near the planet's center. The core temperature may be about 43,000 degrees Fahrenheit (24,000 degrees Celsius), hotter than the surface of the sun.

The most outstanding feature on Jupiter's surface is the Great Red Spot, a storm of gas that swirls at a speed of about 225 miles (360 kilometers) per hour at its edge. The spot -- which has been shrinking -- has a diameter equal to about three times that of Earth.

Solar Thermal Heats Up

The hitch with solar power has always been its sky-high cost: the sun may be free, but the materials and the equipment needed to convert rays into electricity certainly aren't. That's why entrepreneurs have long been searching for a way to create a solar company with an economic model that resembles a software startup--selling a sophisticated computer program that drives cheap, commodity hardware.

Bill Gross, founder of the startup incubator Idealab, based in Pasadena, CA, believes that he's got it: an enterprise designed to kick off what he calls a "disruptive revolution" in carbon-free energy. A serial entrepreneur who has launched more than 30 tech companies, Gross is CEO of eSolar, a Pasadena-based solar thermal venture that will go live with a five-megawatt test bed of its utility-scale technology on the grid later this summer.

But that's only a tiny fraction of what's to come. The privately held eSolar and its power plant operating partner, NRG Energy, have announced agreements with three electric utilities to install 500 megawatts of thermal solar capacity over the next few years.

To put that into perspective, that is more than the current 450 megawatts of solar thermal capacity that's online in the United States today, says Daniel Englander, a solar energy analyst with GTM Research, in Cambridge, MA. And it's a significant fraction of the total of 1.5 gigawatts of photovoltaic solar capacity currently installed nationwide.

The agreements--with Pacific Gas and Electric, Southern California Edison, and El Paso Electric--are aimed at producing power beginning in 2011. While the utilities aren't disclosing the target price for the electricity in the contracts, Gross claims that he can deliver it at about 10 cents per kilowatt-hour--less than the typical rate for wind power or even a natural gas plant.

ESolar's thermal power technology has only a few basic components. Giant fields of tabletop-sized glass panels track and reflect the sun. The beams shoot at towers where water is boiled to make steam that can drive a traditional turbine. Meanwhile, special software that costs $100 million to develop runs on a bank of Dell servers. The software coordinates with cheap video cameras that continually monitor the angle of the panels as the sun rises and sets.

Other companies, such as Brightsource Energy, have also developed solar thermal technology using central towers and boilers. But what's new about eSolar's approach, says Daniel Englander, is that the mirrors are smaller and cheaper to make and install, thus requiring more sophisticated control software.

Utility-scale thermal solar plants have been around for decades, the largest of which is the set of Kramer Junction plants in the Mojave Desert that produces 350 megawatts of peak power for Southern California Edison. But its massive trough-shaped panels, which harness the sun, are expensive to make and install, in large part because they require so much steel to support the parabolic-shaped glass panels.

However, a large amount of new thermal solar power capacity is being planned using newer technology. Currently, there's more than eight gigawatts of thermal solar capacity being promised to U.S. utilities; how much of that will actually get built is unclear. "A lot of these contracts in California that the utilities are signing aren't with an eye to actually building," Englander says. "A lot of times, it's just a good-faced effort to show that they're engaged with renewable energy."

Later this month, eSolar's 24,000-panel plant in Lancaster, CA, is set to begin supplying its power for the grid. However, since the plant is self-financed and company operated, no one outside eSolar will be able to verify the real costs of producing the electricity.

From then on, though, eSolar won't be building its own plants. NRG Energy, based in Princeton, NJ, will purchase eSolar's technology and build, finance, and operate the planned 500 megawatts. NRG currently operates 24 gigawatts of power capacity at dozens of plants powered by a full range of energy sources. Michael Liebelson, NRG's chief development officer for low carbon technology, says that he chose eSolar because "it is the lowest cost of all solar solutions."

Biotech Bacteria Could Help Diabetics

Friendly gut microbes that have been engineered to make a specific protein can help regulate blood sugar in diabetic mice, according to preliminary research presented last week at the American Chemical Society conference in Washington, D.C. While the research is still in the very early stages, the microbes, which could be grown in yogurt, might one day provide an alternative treatment for people with diabetes.

The research represents a new take on probiotics: age-old supplements composed of nonharmful bacteria, such as those found in yogurt, that are ingested to promote health. Thanks to a growing understanding of these microbes, a handful of scientists are attempting to engineer them to alleviate specific ailments. "The concept of using bacteria to help perform (or fix) human disorders is extremely creative and interesting," wrote Kelvin Lee, a chemical engineer at the University of Delaware, in Maryland, in an e-mail. "Even if it does not directly lead to a solution to the question of diabetes, it opens up new avenues of thought in a more general sense," says Lee, who was not involved in the research.

People with type 1 diabetes lack the ability to make insulin, a hormone that triggers muscle and liver cells to take up glucose and store it for energy. John March, a biochemical engineer at Cornell University, in Ithaca, NY, and his collaborators decided to re-create this essential circuit using the existing signaling system between the epithelial cells lining the intestine and the millions of healthy bacteria that normally reside in the gut. These epithelial cells absorb nutrients from food, protect tissue from harmful bacteria, and listen for molecular signals from helpful bacteria. "If they are already signaling to one another, why not signal something we want?" asks March.

The researchers created a strain of nonpathogenic E. coli bacteria that produce a protein called GLP-1. In healthy people, this protein triggers cells in the pancreas to make insulin. Last year, March and his collaborators showed that engineered bacterial cells secreting the protein could trigger human intestinal cells in a dish to produce insulin in response to glucose. (It's not yet clear why the protein has this effect.)

In the new research, researchers fed the bacteria to diabetic mice. "After 80 days, the mice [went] from being diabetic to having normal glucose blood levels," says March. Diabetic mice that were not fed the engineered bacteria still had high blood sugar levels. "The promise, in short, is that a diabetic could eat yogurt or drink a smoothie as glucose-responsive insulin therapy rather than relying on insulin injections," says Kristala Jones Prather, a biochemical engineer at MIT, who was not involved in the research.

Creating bacteria that produce the protein has a number of advantages over using the protein itself as the treatment. "The bacteria can secrete just the right amount of the protein in response to conditions in the host," says March. That could ultimately "minimize the need for self-monitoring and allow the patient's own cells (or the cells of the commensal E. coli) to provide the appropriate amount of insulin when needed," says Cynthia Collins, a bioengineer at Rensselaer Polytechnic Institute, in Troy, NY, who was not involved in the research.

In addition, producing the protein where it's needed overcomes some of the problems with protein-based drugs, which can be expensive to make and often degrade during digestion. "Purifying the protein and then getting past the gut is very expensive," says March. "Probiotics are cheap--less than a dollar per dose." In underprivileged settings, they could be cultured in yogurt and distributed around a village.

The researchers haven't yet studied the animals' guts, so they don't know exactly how or where the diabetic mice are producing insulin. It's also not yet clear if the treatment, which is presumably triggering intestinal cells to produce insulin, has any harmful effects, such as an overproduction of the hormone or perhaps an inhibition of the normal function of the epithelial cells. "The mice seem to have normal blood glucose levels at this point, and their weight is normal," says March. "If they stopped eating, we would be concerned."

March's microbes are one of a number of new strains being developed to treat disease, including bacteria designed to fight cavities, produce vitamins and treat lactose intolerance. March's group is also engineering a strain of E. coli designed to prevent cholera. Cholera prevention "needs to be something cheap and easy and readily passed from village to village, so why not use something that can be mixed in with food and grown for free?" says March.

However, the work is still in its early stages; using living organisms as therapies is likely to present unique challenges. More research is needed to determine how long these bacteria can persist in the gut, as well as whether altering the gut flora has harmful effects, says MIT's Prather.

In addition, recent research shows that different people have different kinds of colonies of gut bacteria, and it's unclear how these variations might affect bacterial treatments. "This may be particularly challenging when it comes to determining the appropriate dose of the therapeutic microbe," says Collins at Rensselaer. "The size of the population of therapeutic bacterial and how long it persists will likely depend on the microbes in an individual's gut."