Scientists Estimate 20 Billion Earth-Like Planets In Our Galaxy

An artist's rendition of Kepler-69c, a super-Earth-size planet in the habitable zone of a star like our sun, located about 2,700 light-years from Earth in the constellation Cygnus.

AP An artist's rendition of Kepler-69c, a super-Earth-size planet in the habitable zone of a star like our sun, located about 2,700 light-years from Earth in the constellation Cygnus.

AP

A new study suggests there could be far more Earth-like planets orbiting distant stars than once thought, some of which might even harbor life.

A team of astronomers from the University of California, Berkeley and the University of Hawaii at Manoa, Honolulu, used the Kepler space telescope to survey 42,000 Sun-like stars looking for a telltale dimming caused by an orbiting planet as it crosses between us and the parent star.

While the method is not new, in the past it has tended to favor finding larger planets orbiting close in – lots of so-called "hot Jupiters" that are way too big and/or way too close to their stars to be candidates for life. Kepler's main mission has been to find planets in what astronomers call the "Goldilocks Zone" — not too hot and not too cold and just the right size for life as we know it to evolve.

The team publishing in the latest issue of PNAS looked at how frequently the dimmings took place to determine the orbital period — and therefore the distance from the star — as well as how much light was blocked, which gives an indication of the size of the planet:

"We found 603 planets, 10 of which are Earth size and orbit in the habitable zone, where conditions permit surface liquid water," the team writes. "We find that 22 percent of Sun-like stars harbor Earth-size planets orbiting in their habitable zones. The nearest such planet may be within 12 light-years."

Smithsonian says:

"Over the past 18 years, astronomers have discovered 1038 planets orbiting distant stars. Disappointingly, though, the vast majority don't seem like candidates to support life as we know it—they're either so close to their home star that all water would likely evaporate, or so far away that all of it would freeze, or they're made up of gas instead of rock and more closely resemble our solar system's gas giants than Earth."

Andrew Howard, one of the study's co-authors, enthused at a recent news conference that their 22 percent figure means that "with about 100 billion stars in our Milky Way galaxy, that's about 20 billion such planets. ... That's a few Earth-sized planets for every human being on the planet Earth."

And, that's just in a single galaxy. If the figure for potentially habitable planets derived by the team of scientists is correct, we could take a minor flight of fancy and multiply the 20 billion planets by about 500 billion galaxies in the observable universe for a truly astronomical number – possibly 10 trillion Earth-like planets.

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AIDS Scientists Encouraged By Antibodies That Hit Monkey Virus

These HIV viruses even look a little like bull's-eyes.

A. Harrison and P. Feorino/CDC These HIV viruses even look a little like bull's-eyes.

A. Harrison and P. Feorino/CDC

Scientists have a new idea for beating HIV: Target the virus with guided missiles called monoclonal antibodies.

At least in monkeys infected with an experimental virus similar to the human AIDS virus, the approach produced what researchers call "profound therapeutic efficacy."

The results appear Thursday in two papers published by Nature — one from a Boston group and a confirmatory report from the National Institute of Allergy and Infectious diseases.

The virus plummeted to undetectable levels in animals that got potent antibodies of a type recently discovered in some humans with HIV. And the virus remained undetectable for weeks after a single antibody injection.

“ This is a really new wrinkle in a field that needs new wrinkles

- Dr. Francis Collins

Most impressive, several monkeys who started out with low levels of HIV in their blood maintained extremely low levels of the virus in their systems months after a single antibody injection.

The researchers think they may have turned these animals into so-called elite controllers — like the 1 percent of HIV patients who are able to suppress the virus even without antiviral drugs.

The scientists say their results justify experiments in humans with HIV. And the potential implications seem to be large, in at least two ways:

Periodic injections of monoclonal antibodies might be a new kind of treatment for HIV-infected humans, either alone or in combination with conventional antiviral drugs.Monoclonal antibodies might be incorporated into strategies, now being eagerly pursued by a number of scientists, to cure HIV infection — that is, to clear the virus from patients' cells, allowing them to stop taking antiviral drugs.

"The findings of these two papers could revolutionize efforts to cure HIV," two cure-seekers write in a Nature commentary. Why? Louis Picker of Oregon Health and Science University and Steven Deeks of the University of California, San Francisco speculate that combining monoclonal antibodies with conventional antiviral drugs might turbocharge the suppression of HIV, stimulate the destruction of reservoirs of HIV-infected cells, and suppress the generalized immune activation that accompanies chronic HIV infection.

"At the very least, these results will catalyse collaborations between the massive teams of experts who have for decades worked on HIV prevention and treatment in separate venues," Picker and Deeks predict.

The findings stem from discoveries over the past year or so that some humans with HIV occasionally make antibodies to the virus that are highly potent. That insight came after years of disappointing efforts to find what researchers call broadly neutralizing antibodies against HIV — or to stimulate their production with experimental vaccines.

Dan Barouch of Beth Israel Deaconess Medical Center in Boston and his colleagues generated several types of the newly discovered antibodies in mice. They then injected the antibodies into 18 rhesus monkeys that had been infected nine months earlier with a specially concocted virus with features of both HIV (the human AIDS virus) and SIV (the simian, or monkey, version). The hybrid virus, which doesn't appear in nature, is called SHIV.

The antibody injections resulted in rapid clearance of free-floating SHIV from the animals' blood that was sustained for weeks or months, until the antibodies gradually disappeared.

There was also evidence that the antibodies stimulated the monkeys' own immune systems to target and kill the cells infected by SHIV. That needs confirmation, but if it happens that would be important because long-term control of infection requires the elimination of these hiding places — the cells that harbor viral genes that can give rise to new HIV.

The durability of the antibody treatment varied according to how much SHIV the monkeys had in their systems to start with.

The Boston researchers were so surprised by their findings that they didn't publish them until the NIH group replicated them in a smaller study.

Other scientists say the implications of this early immunotherapy study are potentially far-reaching. NIH Director Francis Collins told The Wall Street Journal that he could imagine shifting HIV treatment from daily antiviral pills to injections of monoclonal antibodies every three months. "This is a really new wrinkle in a field that needs new wrinkles," Collins says.

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Scientists: Asian Carp Breeding In Great Lake Tributaries

Tommy Goszewski, a technician with the U.S. Geological Survey, holds a grass carp taken from a pond at an agency lab in Columbia, Mo., in spring 2013.

AP Tommy Goszewski, a technician with the U.S. Geological Survey, holds a grass carp taken from a pond at an agency lab in Columbia, Mo., in spring 2013.

AP

Scientists have confirmed for the first time that at least one variety of Asian carp is living and breeding in the Great Lakes watershed, where it threatens stocks of native fish.

A U.S. Geological Survey and Bowling Green State University study published Monday says Asian carp taken from the Sandusky River in Ohio show the fish are "the result of natural reproduction within the Lake Erie basin."

"It's bad news," USGS Duane Chapman told The Associated Press. "It would have been a lot easier to control these fish if they'd been limited in the number of places where they could spawn. This makes our job harder. It doesn't make it impossible, but it makes it harder."

According to a USGS statement:

"If grass carp become abundant in Lake Erie, they may threaten native fish populations and could be detrimental to ducks, geese or other large aquatic birds. Grass carp were brought to the U.S. to control aquatic plants in the 1960s. They eat large quantities of aquatic plants, which could degrade areas important for spawning and early development of native fish."

While other species of Asian carp are of more concern than the Grass carp, all Asian carp require similar conditions to successfully reproduce, scientists say.

The AP reports:

"Of greatest concern in the Great Lakes region are bighead and silver carp, prolific breeders that gobble huge amounts of plankton — tiny plants and animals that are vital to aquatic food chains. Scientists say if they gain a foothold in the lakes, they could spread widely and destabilize a fishing industry valued at $7 billion."

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