Water is all about extremes. The atoms that make up water molecules were forged in some of the hottest environments in the universe. But most of the molecules formed in the cold of deep space.
A water molecule consists of two hydrogen atoms plus one oxygen atom – H-2-O. A hydrogen atom contains one electron and one proton. The electrons formed in the first fraction of a second after the Big Bang, when the universe was extremely hot and dense. The protons formed a few minutes later.
By about 380,000 years, the universe had expanded and cooled enough for the electrons and protons to stick together to form atoms. And today, hydrogen accounts for more than 90 percent of all the atoms in the universe.
Hydrogen and helium, the other major element forged in the Big Bang, soon came together to make stars. And a star’s core is hot enough to “fuse” lighter elements to create heavier ones.
The first steps in that process create carbon, nitrogen, and especially oxygen – the third-most abundant element in the universe. When stars die, they expel some of those elements into space. And in the cold away from the stars, hydrogen and oxygen can stick together to make molecules of water. Some of the water’s incorporated into planets – including our own.
So the next time you take a cool drink of water, think of the hot-and-cold origins of this important compound.
We’ll have more about water tomorrow.
Script by Damond Benningfield
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Moon and Heart
To have a strong heart, you naturally need strong arteries. And that’s not a problem for Antares, the heart of the scorpion. It’s flanked by two fairly bright stars that historically have shared a name: Alniyat – an Arabic name that means “the arteries.”
The stars probably are siblings of Antares. They all formed from the same giant complex of gas and dust, within the past 10 million years or so.
Alniyat I is also known as Sigma Scorpii. It’s a system of four stars. Two of them form a tight pair, with a third close by. The fourth star is farther out.
Both stars in the tight grouping are much like Antares. They’re many times the mass of the Sun, so they’ll probably end their lives with titanic explosions. Antares is a little farther along its lifecycle, so it’s closer to that showy demise.
Alniyat II is Tau Scorpii. It’s a single star. It, too, is destined to explode as a supernova, but not for several million years – a little later than Antares and the main star of Sigma. On the astronomical clock, though, that’s close – just a few ticks away.
Antares and its arteries are close to the right of the Moon at nightfall this evening. Sigma is close to the right or upper right of Antares. Tau is about the same distance to the lower left of Antares. The arteries aren’t as bright as the scorpion’s heart, though, so you might need binoculars to see them through the glare.
Script by Damond Benningfield
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Venus Flyby
A spacecraft that’s on it way to Jupiter is “pinballing” around the solar system, getting an extra “kick” as it zips close to the planets. It’ll get the next kick tomorrow, from Venus.
The spacecraft is JUICE – Jupiter Icy Moons Explorer. It’s scheduled to arrive at Jupiter in 2031. But it needs help to get there. And it gets that help from the gravity of Venus, Earth, and the Moon.
During each encounter, the craft “steals” a bit of gravitational energy. That speeds it up and sculpts its path around the Sun. The encounters drastically reduce the amount of fuel JUICE must carry, cutting its size and weight and reducing its cost. JUICE flew past Earth and the Moon a year ago. It’ll get additional boosts from Earth in 2026 and ’29.
JUICE will scan Venus as it flies past. That will give scientists some extra information about the planet. And it’ll give engineers a chance to check out the craft’s instruments.
When JUICE arrives at Jupiter, it’ll orbit the planet for almost three years. After that, it’ll begin orbiting the planet’s largest moon, Ganymede. Its observations of Ganymede and Jupiter’s other icy moons will reveal details about their possible buried oceans, which could be habitats for microscopic life.
Venus and Jupiter are in the dawn sky now. Venus is the brilliant “morning star,” with slightly fainter Jupiter to its upper right – two destinations for a “pinballing” explorer.
Script by Damond Benningfield
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Seeing Planets
Only a few of the thousands of known planets in other star systems have ever been seen. Most exoplanets are discovered through their effects on their parent stars. But a system in Pegasus is a major exception. Astronomers have discovered four planets in the system – and they’ve seen all of them.
HR 8799 is about 130 light-years from Earth. The star is bigger, brighter, and heavier than the Sun. And it’s much younger – tens of millions of years, versus four and a half billion years for the Sun. And that’s one reason we can see the planets – they’re still warm from their birth, so they produce a lot of infrared light.
Another reason we can see the planets is that they’re a long way out from the star – many times the distance from Earth to the Sun – so they’re not masked by the star’s light. And the planets are giants – they’re up to 10 times the mass of Jupiter, the giant of our own solar system.
Recent observations by Webb Space Telescope suggest the planets formed in the same way as Jupiter. Blobs of rock and metal stuck together to form a heavy core. The gravity of the core then swept up huge amounts of gas.
The system might still be taking shape. A giant disk of dust surrounds the planets, and is being stirred up by their gravity. And the planets themselves may be shifting position – finding the right arrangement before this young, busy system settles down.
Script by Damond Benningfield
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Vanishing Planet
A recently discovered planet is facing its final days. It’s evaporating, leaving a trail of debris that stretches halfway along its orbit.
The planet is known by a catalog number – BD +05 4868 Ab. It’s only the fourth evaporating planet ever seen.
It orbits the main star in a binary system in Pegasus, which is in the eastern sky at nightfall. The star is smaller and fainter than the Sun, and more than twice the age of the Sun.
The planet was discovered by TESS, a planet-hunting space telescope. The planet passes in front of its parent star once every 30.5-hour orbit, blocking some of the star’s light. But the dips in starlight are ragged and look different from orbit to orbit. That suggests the planet is shedding material, forming a lumpy trail.
The planet is small, and it orbits the star at just two percent of the distance from Earth to the Sun. At that range, it’s heated to 3,000 degrees Fahrenheit. That vaporizes minerals at the surface. The vapor boils into space, where it cools and condenses to form solid grains. That creates a thick trail that extends both behind and ahead of the planet.
As more of the planet vaporizes, its gravity weakens, allowing even more material to escape. So the planet could vanish entirely in as little as a million years.
Astronomers will look at the system with Webb Space Telescope – revealing more details about this vanishing planet.
Script by Damond Benningfield
USA