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This week on Our World: A new role for coral reefs as cradles of evolution ... a White House initiative on science education ... and solving a lead-poisoning mystery among immigrant children.
HESTING: "We were hunting around for anything we could find that these kids might be getting into. We tested food, we tested toys – anything that we thought that that baby could have come into contact with."
Those stories, using science to free wrongfully-convicted prisoners, and more...
I'm Art Chimes. Welcome to VOA's science and technology magazine, "Our World."
New images from the earth-orbiting Hubble Space Telescope show galaxies forming a "mere" 600 million years after the Universe was born in the so-called "Big Bang" – more than 13 billion years ago.
The galaxies are the oldest ever observed, indicating that these vast clusters of stars were starting to form earlier in the history of the Universe than previously believed.
Astronomers say these galaxies are much smaller than our own Milky Way galaxy, and they describe them as "primordial," with fewer heavy elements than galaxies that formed later.
Another space telescope is in the news this week. Scientists on Monday (January 4) reported the first planets discovered by the Kepler Space Telescope, which was launched in March last year specifically to find planets orbiting distant stars.
Kepler was designed to look for planets like Earth, but as expected early in its mission, the first discoveries are much bigger planets – four of them bigger than Jupiter, and a fifth roughly the size of Neptune.
NASA scientist William Borucki says these planets race around their stars so fast, that their years are measured in days.
BORUCKI: "The orbital periods run from about 3.2 days to 4.9 days. So these are very short orbits. The short period orbits also tell us that the planets are orbiting close to their stars, and consequently you're going to see they're quite hot."
How hot? Astronomers use the Kelvin scale, which starts at absolute zero. So frigid Jupiter is 124 Kelvin, Earth is about 300 Kelvin.
BORUCKI: "If you continue going up in temperature, you see molten lava at about 1300 Kelvin. The planets we found are all hotter than molten lava. They all simply glow with their temperatures. Looking at them might be like looking at a blast furnace. They are very bright in their own right."
Borucki and other Kepler astronomers discussed the newly-discovered planets at the American Astronomical Society meeting in Washington.
The Kepler orbiting telescope can't see planets directly. Looking into deep space with even the best telescope, you can't see a planet next to the large, bright glare of the star it's orbiting. So instead, astronomers look for the light of the star to dim slightly as a planet passes in front of it. Kepler is continuously monitoring more than 100,000 stars considered likely to have planets.
The challenge is weeding out false positives, when a star dims for some other reason.
BATALHA: "Well, fortunately we have a very well laid-out plan for vetting out these false positives."
San Jose State University astronomer Natalie Batalha told reporters that some of those false positives can be eliminated by the precision and stability of Kepler's observations. But in other cases, astronomers rely on ground-based observations to confirm the finding from Kepler. It required almost 100 nights of observations from telescopes in the U.S. and the Canary Islands to confirm discovery of the five planets reported this week:
BATALHA: "So that gives you a feel for the process, how long it takes from start to finish and how careful we are in confirming and making sure these are real signals."
Kepler's high precision is not just useful in identifying new planets around distant stars. It can tell astronomers something about the stars themselves as well as providing more detailed information about the planets it is discovering.
Ron Gilliland of the Space Telescope Science Institute says the size of one star was measured by ground telescopes to an accuracy of plus or minus 10 percent; with Kepler, the uncertainty was reduced to just 1 percent. And likewise, Kepler has refined measurements of a planet in orbit around that star.
GILLILAND: "Before Kepler, we would have known the density of the exoplanet orbiting this star to maybe 50 percent accuracy. After Kepler, we should know that to about 5 percent accuracy. And that's absolutely critical to hope to understand the interior structure of the planets." (:16)