StarDate

The goddess of the dawn has given millions of Americans a rare treat the past couple of years: brilliant displays of the northern lights in regions where they’re seldom seen. Today, we know that these colorful curtains of light are powered by storms on the Sun. Bigger storms expand the viewing area. But in centuries past, cultures around the globe created their own explanations.

In Scandinavia, for example, the northern lights might have represented Bifrost, the “rainbow bridge” that connected Earth to Asgard, the home of the gods. In some of the islands of Scotland, the lights represented a pair of chieftains fighting for the hand of a “merry dancer.”

In southern England, they were considered omens of misfortune. Some saw the lights as clashing swords; red lights were streamers of blood. During an intense outburst in March 1716, at the end of a civil war, people ran into the streets in their nightclothes, and some thought it was judgment day. One writer said that some “read in its glaring visage, the fate of nations and the fall of kingdoms.”

The name for the northern lights – the aurora borealis – was bestowed in 1619 by Italian astronomer Galileo Galilei. Aurora was the Roman goddess of the dawn. Boreas was the Greek god of storms and the north wind – one of the namesakes of the always beautiful, sometimes frightening northern lights.

More about the aurora tomorrow.

Script by Damond Benningfield

Sixty years ago today, NASA was making its first attempt to land on the Moon.
Surveyor 1 had been launched three days earlier.

The robotic lander touched down in a crater in the Ocean of Storms – a giant volcanic plain. It was a precursor to the Apollo missions, which would land astronauts on the Moon.

Surveyor wasn’t the first probe to land on the Moon – a Soviet mission beat it by a few months. But Surveyor was more sophisticated. It carried a television camera to beam back images of its surroundings.

Surveyor transmitted its first pictures just minutes after landing. And during its first lunar “day” – almost 14 Earth days – it snapped more than 10 thousand images. They showed a surface coated with small rocks, and pockmarked by small craters. The rim of the crater Surveyor landed in was visible in the distance.

Pictures of its landing pads revealed important details about the texture of the lunar surface, as this NASA documentary pointed out:

 ANNOUNCER: The lunar surface texture not thick layers of loose dust into which spacecraft or men could sink. In the area of the Ocean of Storms, man can land and walk on the lunar surface.

Surveyor 1 survived the frigid lunar night, taking hundreds more pictures the next day. Scientists even raised it the following January – seven months after its historic landing on the Moon.

Script by Damond Benningfield

The twins of Gemini have a front-row seat for a planetary waltz this month. Venus, Jupiter, and Mercury are close to the twins now, and will bunch up even closer as the month progresses.

The “twins” are the stars Pollux and Castor. They’re about a quarter of the way up the western sky as evening twilight fades. Pollux is the brighter of the two, with Castor to its right.

Jupiter looks like a brilliant star to the lower left of the twins. It’s the largest planet in the solar system. But it’s on the far side of the Sun as seen from Earth, so it’s more than 550 million miles away – about six times the distance between Earth and the Sun.

Venus is even brighter – the “evening star.” It’s below the twins. Although it’s a little smaller than Earth, it shines much brighter than Jupiter mainly because it’s much closer to both Earth and the Sun.

Venus and Jupiter remain in view for a good while after darkness falls. That’s not the case for Mercury. It’s well to the lower right of the others, and much lower in the sky. It’s bright, though, so with a clear horizon, there’s a good chance to spot it.

Mercury will move a little higher into the sky over the next few nights, improving the view. But the real action involves Jupiter and Venus. Venus is climbing away from the Sun quickly. It will nestle especially close to Jupiter on the 8th and 9th. It’ll pull away after that – all in close view of the twins.

Script by Damond Benningfield

It’s early in the long winter night at the south pole. But a few dozen scientists and others have settled in at a research base there. They monitor the weather and climate, listen to rumbles in the ice below, and watch auroras dancing in the dark skies above. And they operate observatories that study the universe beyond.

One of those observatories is buried in the ice. Known as IceCube, it’s a set of thousands of light detectors. They look for evidence of neutrinos – particles that are produced in the Sun, exploding stars, and other powerful objects and events. They almost never interact with other matter. But when one does interact, by smashing into an ice molecule, it produces a quick flash of light. Studying that flicker reveals details about the neutrino, including its origin. And that tells scientists more about the body that created it.

Another observatory, the South Pole Telescope, studies the “afterglow” of the Big Bang. Known as the cosmic microwave background, it’s a sort of “haze” that fills the entire universe. Tiny fluctuations in the haze reveal details about the birth of the first stars and galaxies.

Water vapor in the atmosphere absorbs microwaves. But the south pole is almost two miles high, and it’s so cold that there’s almost no water vapor in the skies above it. That allows the 10-meter dish to study the background glow in great detail – under the clear, dark skies at the bottom of the world.

Script by Damond Benningfield

The Moon can be like a painter’s canvas, dabbed with many colors: the silver of a frosty night, the gold of honey, the orange of a ripe cantaloupe, even the deep red of blood. But it’s almost never blue – at least not in appearance. It sometimes is blue in name, though – including tonight. That’s because it’s the second full Moon of May – a repeat appearance known as a Blue Moon.

The color of the Moon – full or not – depends on several factors. When the Moon is low in the sky, as it rises or sets, its light passes through a thicker layer of air. Molecules in the atmosphere scatter blue wavelengths of light, allowing the red to shine through.

As the Moon climbs higher, we see more of its true color – gray. But the Moon is so bright that it looks white or silver.

During a lunar eclipse, the Moon passes through Earth’s dark shadow. But sunlight filtering through Earth’s atmosphere makes the Moon look dark orange or red.

In rare cases, the Moon can actually look blue. That happens after volcanic eruptions or big forest fires. These events pump out particles that scatter red light, allowing the blue to shine through. After the eruption of Krakatoa, in 1883, the Moon appeared blue for months around the entire globe.

Whatever its color, enjoy tonight’s Blue Moon. And look quite close to it throughout the night for the star Antares, the heart of the scorpion. They’ll be closest as they set.

Script by Damond Benningfield