StarDate

A thousand spacecraft could head for our closest neighboring planetary system in just a few decades. Don’t book your ticket just yet, though – each craft would weigh about as much as a penny. But working together, they could provide a few sharp pictures of the system, and even look for signs of life.

A team of scientists and engineers published the idea earlier this year. The team proposed sending the probes to Proxima Centauri. It’s the closest star outside the solar system – four-and-a-quarter light-years away. And it has two confirmed planets. One of them is about the size and mass of Earth, and it’s in the region that’s most comfortable for life.

The probes would be equipped with tough but thin “sails” 13 feet wide. A powerful laser would fire at each probe for eight minutes. The pressure of the light would boost the probes to 20 percent of the speed of light. It would take them 21 years to reach their target.

The probes would use lasers to stay in touch with each other, and with Earth. About 300 probes could survive the trip. Their instruments could hunt for evidence of life in the planets’ atmospheres.

There’s a lot of work to make it happen – advances in materials, lasers, computers, and even our knowledge of the distance to Proxima Centauri. But the researchers said the current rate of advancement should make such a trip feasible in the decades ahead.

Script by Damond Benningfield

The winds on a giant planet more than 200 light-years from Earth are like the Big Bad Wolf: they’ll huff and puff and blow your house down. And if that’s not enough of a problem, the temperature can jump by 500 degrees in just a few hours.

The planet orbits the star HD 80606. The star is a lot like the Sun. And it has a distant companion star that’s a near twin. They’re in Ursa Major, the great bear. At dawn, the system stands to the upper right of the Big Dipper, although you need a telescope to see it.

The planet is HD 80606 b. It’s about four times the mass of Jupiter, the giant of our own solar system. But it’s about the same size as Jupiter, so it’s much denser.

Its orbit is one of the most elongated of any known planet – its distance ranges from just three million miles to 85 million. As the planet approaches the star, it’s like being popped into an oven: The amount of energy it receives when it’s closest to the star is 800 times greater than when it’s farthest. So the planet heats up in a hurry.

The approach also stirs up the winds. They blow outward from the point that’s in the middle of the hemisphere that faces the star. They may top out at 11,000 miles per hour – huffin’ and puffin’ all the way around this turbulent planet.

Script by Damond Benningfield

The Moon huddles close to the heart of the scorpion this evening – the star Antares. It’s among the 15 brightest star systems in the night sky.

If our eyes could see all forms of light, Antares would look perhaps 10 times brighter still. That’s because it emits most of its energy in the infrared – wavelengths that are too long for the human eye to perceive.

All stars emit radiation across the electromagnetic spectrum – from radio waves to X-rays. That includes the Sun. But the mix of wavelengths depends on the star’s surface temperature, which we see as its color.

Stars like the Sun are yellow-white. Their energy peaks at visible wavelengths – the type of energy our eyes have evolved to see.

Stars that are hotter than the Sun look white or blue. But their light peaks beyond those colors – mainly in the ultraviolet – wavelengths that are much too short for us to see.

Antares, on the other hand, is thousands of degrees cooler than the Sun, so it looks orange. But it emits most of its light in the infrared.

And it produces a lot of it. The star is a supergiant – far bigger than the Sun. At visible wavelengths, it shines about 10,000 times brighter than the Sun. Throw in the infrared and all the other wavelengths, and it could be a hundred thousand times the Sun’s total brightness – one of the true stunners in our part of the galaxy.

Tomorrow: A planetary Big Bad Wolf.

Script by Damond Benningfield

The first planet ever discovered orbiting a Sun-like star is nothing like anything in our own solar system. But it helped astronomers learn more about the history of the solar system.

The planet orbits 51 Pegasi. The star is a little bigger, heavier, and brighter than the Sun. The planet is 51 Pegasi b. It’s about half as heavy as Jupiter, the giant of the solar system. But it’s much closer in – just a few million miles from the star.

The planet’s gravity causes the star’s light to “wobble” a bit. Precise measurements of that wobble revealed the planet’s details. Astronomers have since discovered hundreds more planets with the same technique, including many planets that are “hot Jupiters” like 51 Pegasi b.

There’s no way for such a massive planet to form so close to its star. So it must have been born much farther out, then migrated to its current location.

That realization led to theories that the Sun’s giant planets shifted around when the solar system was young. And that could have nudged the small inner planets, including Earth. It might even have pushed closer planets into the Sun – destroying some of Earth’s planetary siblings.

Pegasus is in the east at nightfall. Look for four moderately bright stars that form the Great Square, which is tilted on its side. 51 Pegasi is along the top right side of the tilted square. Under dark skies, it’s barely visible to the eye alone.

Script by Damond Benningfield

Pegasus has a bit of an identity crisis. The stars that outline its body – the Great Square – don’t all belong to the flying horse. In fact, the brightest of the four stars officially belongs to Andromeda.

The Great Square is in the east at nightfall. Its member stars are all bright enough to see even through moderate light pollution. The square is tilted, so it looks more like a diamond than a square.

Its brightest member forms the left point of the diamond – the star Alpheratz. It’s about a hundred light-years from Earth. And it consists of two stars, both of which are a good bit bigger, brighter, and heavier than the Sun.

In earlier centuries, Alpheratz was considered a member of both Pegasus and Andromeda – it’s a prominent member of the classical outlines of both constellations.

But in the early 20th century, astronomers decided to formalize the constellations. In 1930, they adopted a list of 88 constellations and gave them precise boundaries, like the borders of states or nations. That meant that every star could belong to only one constellation. The way the borders were drawn, Alpheratz stayed with Andromeda.

There’s no way to not see the star as part of the Great Square. So unofficially, Alpheratz maintains its dual citizenship: the second-brightest star of Andromeda, and the brightest star of the Great Square of Pegasus.

We’ll have more about the flying horse tomorrow.

Script by Damond Benningfield