Apollo 8: Christmas at the Moon

Apollo 8, the first manned mission to the moon, entered lunar orbit on Christmas Eve, Dec. 24, 1968. That evening, the astronauts held a live broadcast from lunar orbit, during which they showed pictures of the Earth and moon as seen from their spacecraft.

Christmas Eve, 1968. As one of the most turbulent, tragic years in American history drew to a close, millions around the world were watching and listening as the Apollo 8 astronauts -- Frank Borman, Jim Lovell and Bill Anders -- became the first humans to orbit another world.

As their command module floated above the lunar surface, the astronauts beamed back images of the moon and Earth and took turns reading from the book of Genesis, closing with a wish for everyone "on the good Earth."

"We were told that on Christmas Eve we would have the largest audience that had ever listened to a human voice," recalled Borman during 40th anniversary celebrations in 2008. "And the only instructions that we got from NASA was to do something appropriate."

"The first ten verses of Genesis is the foundation of many of the world's religions, not just the Christian religion," added Lovell. "There are more people in other religions than the Christian religion around the world, and so this would be appropriate to that and so that's how it came to pass."

The mission was also famous for the iconic "Earthrise" image, snapped by Anders, which would give humankind a new perspective on their home planet. Anders has said that despite all the training and preparation for an exploration of the moon, the astronauts ended up discovering Earth. 

The Apollo 8 astronauts got where they were that Christmas Eve because of a bold, improvisational call by NASA. With the clock ticking on President Kennedy's challenge to land on the moon by decade's end, delays with the lunar module were threatening to slow the Apollo program. So NASA decided to change mission plans and send the Apollo 8 crew all the way to the moon without a lunar module on the first manned flight of the massive Saturn V rocket.

The crew rocketed into orbit on December 21, and after circling the moon 10 times on Christmas Eve, it was time to come home. On Christmas morning, mission control waited anxiously for word that Apollo 8's engine burn to leave lunar orbit had worked. They soon got confirmation when Lovell radioed, "Roger, please be informed there is a Santa Claus."

The crew splashed down in the Pacific on December 27. A lunar landing was still months away, but for the first time ever, men from Earth had visited the moon and returned home safely.

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Alien Earths Could Form Earlier Than Expected

Earth

ScienceDaily (June 13, 2012) —Building a terrestrial planet requires raw materials that weren't available in the early history of the universe. The Big Bang filled space with hydrogen and helium. Chemical elements like silicon and oxygen -- key components of rocks -- had to be cooked up over time by stars. But how long did that take? How many of such heavy elements do you need to form planets?

Previous studies have shown that Jupiter-sized gas giants tend to form around stars containing more heavy elements than the Sun. However, new research by a team of astronomers found that planets smaller than Neptune are located around a wide variety of stars, including those with fewer heavy elements than the Sun. As a result, rocky worlds like Earth could have formed earlier than expected in the universe's history.

"This work suggests that terrestrial worlds could form at almost any time in our galaxy's history," said Smithsonian astronomer David Latham (Harvard-Smithsonian Center for Astrophysics). "You don't need many earlier generations of stars."

Latham played a lead role in the study, which was led by Lars A. Buchhave from the University of Copenhagen and will be published in the journal Nature. The work is being presented June 13 at the 220th meeting of the American Astronomical Society.

Astronomers call chemical elements heavier than hydrogen and helium "metals." They measure the metal content, or metallicities, of other stars using the Sun as a benchmark. Stars with more heavy elements are considered metal-rich while stars with fewer heavy elements are considered metal-poor.

Latham and his colleagues examined more than 150 stars known to have planets, based on data from NASA's Kepler spacecraft. They measured the stars' metallicities and correlated that with the sizes of the associated planets. Large planets tended to orbit stars with solar metallicities or higher. Smaller worlds, though, were found around metal-rich and metal-poor stars alike.

"Giant planets prefer metal-rich stars. Little ones don't," explained Latham.

They found that terrestrial planets form at a wide range of metallicities, including systems with only one-quarter of the Sun's metal content.

Their discovery supports the "core accretion" model of planet formation. In this model, primordial dust accumulates into mile-sized planetesimals that then coalesce into full-fledged planets. The largest, weighing 10 times Earth, can then gather surrounding hydrogen and become a gas giant.

A gas giant's core must form quickly since hydrogen in the protoplanetary disk dissipates rapidly, swept away by stellar winds in just a few million years. Higher metallicities might support the formation of large cores, explaining why we're more likely to find a gas giant orbiting a metal-rich star.

"This result fits with the core accretion model of planet formation in a natural way," said Latham.

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A New, Beautifully Colored Lizard Discovered in the Peruvian Andes

The new colorful lizard has been named Potamites montanicola, or "mountain dweller."

Germán Chávez and Diego Vásquez from the Centro de Ornitología y Biodiversidad (CORBIDI) in Peru have discovered a new colorful lizard which they named Potamites montanicola, or "mountain dweller." The new species was found in Cordillera de Vilcabamba and Apurimac river valley, the Cusco Region of Peru at altitude ranging from 1,600 to 2,100 meters. 

Their study was published in the open access journal ZooKeys.

"The new discovery raises some questions," say the authors. This is the only member of the genus known to live at such altitude. It is yet unknown what biological mechanisms help the lizard to survive in this harsh environment, much colder than what it's relatives in the genus prefer. Scientists also believe the lizard may be nocturnal, which raises the question of how it maintains its body temperature during night time. In some cases, individuals were observed swimming in streams, which is rather unusual behavior for the members this genus.

"Further studies are needed to reveal its biology, population structure and conservation status, and outline its overall distribution," Chávez concludes.

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Dwarf Galaxy Questions Current Galaxy Formation Models

Researcher from the Centro de Astrofísica da Universidade do Porto (Center for Astrophysics of the University of Porto) observed the dwarf galaxy I Zw 18, and found that much of what is known about galaxy formation and evolution might need substantial revision

 CAUP Astronomer Polychronis Papaderos, along with his colleague Göran Östlin (Oskar Klein Center, U. Stokholm), used the Hubble Space Telescope (HST) to get extremely accurate observations of the I Zw 18 galaxy. Their research led to the conclusion that this enigmatic blue compact dwarf might force astronomers to review current galaxy formation models.

I Zw 18 is one of the most studied dwarf galaxies, because among those that have strong star forming activity, it's one of the poorest in heavy elements. Besides, it's proximity to Earth, combined with a total exposure time of nearly 3 days, gave the researchers data with unprecedented resolution and sensitivity.

Analysis of these data revealed an extended gas halo surrounding this galaxy, 16 times larger than the star component of the galaxy, and without any stars. This halo is the result of huge amounts of energy generated by the starburst this galaxy is going through. This energy heats and disturbs I Zw 18's cold gas, which ends up emitting an amount of light comparable to what's being emitted by the stellar component. This emission is designated nebular emission.

Papaderos, a greek astronomer working in Portugal, comments that: "This is ground-breaking work because it provides the first observational proof that, in the early Universe, young galaxies that underwent starbursts must have been surrounded by a huge halo of nebular emission. This extended nebular halo results from the cumulative energetic output from thousands of massive stars exploding as supernovae, shortly after their formation."

So far, in distant galaxies where it's not possible to reach resolutions high enough in order to distinguish between nebular and star emission, it was assumed that the gas occupied the same region as the stars and stars were responsible for emitting most of the light.

This study showed that galaxies undergoing starbursts, similar to I Zw 18, might not obey this rule. This result might lead to substantial corrections in a lot of the work being developed in cosmology and extragalactic astronomy. An example is the estimate of star mass in a galaxy, which is calculated from the galaxies total luminosity. But, as these results shows, up to 50% of that luminosity might originate in nebular, and not star, emission.

Another result from this research shows that, according to Papaderos, "the distribution of nebular emission might be misinterpreted as a stellar disk. These galaxies, still in early stages of formation, might thus be wrongly classified as fully formed galaxies" (such as spirals or ellipticals), a classification mistake that might have happened in many past studies to determine galaxy evolution in the early Universe.

These results are also of importance for our understanding of galaxy formation, because the team concluded that I Zw 18 is extremely young, with most stars younger than 1 billion years. So this galaxy is currently undergoing the dominant phase of its formation, much like the ones formed shortly after the Big Bang.

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