The Blue Danube has been performed for some pretty lofty audiences – kings and queens, emperors and empresses, presidents and prime ministers. But a performance earlier this year topped them all: it was aimed at the stars.
The waltz was composed by Johann Strauss II, who was born 200 years ago today. His birthday was one of the motivations for the performance. The other was the 50th anniversary of ESA – the European Space Agency. So the broadcast was mostly symbolic – not a real attempt to contact other civilizations.
The waltz was performed by the Vienna Symphony Orchestra in late May. It was transmitted to space by one of ESA’s tracking stations.
The waltz was beamed toward Voyager 1. It’s the most-distant working spacecraft in history – more than 15 billion miles from Earth – so far that it took 23 hours for the waltz to reach it. Voyager carries a golden phonograph record inscribed with several musical works – but not the Strauss waltz.
Voyager is passing through Ophiuchus, near the constellation’s brightest star, Rasalhague. It’s about half way up in the west-southwest at nightfall, and it’s easy to see. It’s a bit more than 48 light-years away. So if anyone there happens to point a radio telescope toward Earth in late 2073, perhaps they’ll hear the strains of The Blue Danube waltzing through the galaxy.
Script by Damond Benningfield
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Mirach
A giant companion to a giant star faces an uncertain fate. The star is dying. As it expires, it will blast the companion, drag it inward, zap it with radiation, then loosen its grip on whatever remains.
Mirach is the second-brightest star of Andromeda. It’s passed through the prime phase of life, and now is in the red-giant phase. It’s puffed up to about 85 times the diameter of the Sun, making it shine about 1700 times brighter than the Sun.
Two years ago, astronomers discovered that Mirach has a companion. It’s probably a “failed star” known as a brown dwarf. It’s twice as far from Mirach as Earth is from the Sun.
Before long – astronomically speaking – the star’s outer layers will flow into space at tens of thousands of miles per hour. That will “sandblast” the companion, stripping away some of its bulk. And friction from that material will drag the companion toward the star.
After that, only the star’s hot but dead core will remain – a white dwarf. It’ll pelt the companion with ultraviolet radiation, vaporizing more of it. But the white dwarf will be much less massive than the present star, so it will loosen its gravitational grip on the companion.
No one knows for sure how all of this will play out, so we can’t predict the fate of Mirach’s giant companion.
Mirach is a third of the way up in the east-northeast at nightfall. It’s easy to see, even from most light-polluted cities.
Script by Damond Benningfield
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Fast Eater
The black hole at the heart of a distant quasar has the biggest appetite astronomers have ever seen. It gobbles down the equivalent of one Sun per day – more than any other known black hole. It’s fed by the widest disk of gas and dust yet seen. And it outshines everything else in the known universe – 500 trillion times the Sun’s brightness.
The quasar is so far away that we see it as it looked when the universe was a little more than one-tenth of its current age. It was discovered in the early 1980s, but astronomers thought it was a star. They deciphered its true nature just a couple of years ago.
The heart of the quasar is a black hole 17 billion times the mass of the Sun. That’s not a record, but it’s near the top of the list. The black hole’s enormous gravity pulls in gas, dust, and stars. They form a spinning disk around the black hole. The disk is seven light-years across – half again the distance from the Sun to its closest neighboring star.
As material in the disk funnels toward the black hole, it’s heated to millions of degrees. So the disk shines brilliantly – allowing us to see it across most of the visible universe.
The quasar is in Pictor, the painter’s easel. For skywatchers in the far-southern United States, the constellation is barely in view, low in the south, before dawn. Despite the quasar’s great power, though, it’s much too faint to see without a telescope.
Script by Damond Benningfield
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First Look
We got our first picture from the surface of another planet 50 years ago today, when the Soviet Union’s Venera 9 landed on Venus. It transmitted data from the surface for 53 minutes, including a wide panorama.
Venus is completely covered by thick clouds, so we can’t see its surface from Earth, or even from orbit around Venus – orbiters use radar to peer through the clouds. Venus also has a hot, dense atmosphere, so landing there is tough.
Venera 9 parachuted through the clouds, measuring their thickness and composition. At the surface, it measured the density of the atmosphere – about 90 times the density of Earth’s atmosphere. And it measured the surface temperature – about 900 degrees Fahrenheit.
The lander was supposed to take a full 360-degree view of the landscape. But the lens cap on one of its cameras didn’t pop off as planned, so Venera photographed only half of the scene around it. The image revealed a flat landscape covered with wide, flat rocks. And the lighting was comparable to a cloudy summer day on Earth.
Venera 9 relayed its findings to Earth through an orbiter. Communication ended when the orbiter moved out of range – ending our first direct view of the surface of Venus.
Venus is the beautiful “morning star” this month. It’s low in the east at dawn, and slowly fades from view in the waxing twilight.
Tomorrow: the most ravenous black hole.
Script by Damond Benningfield
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Pulsating Stars
A star in the constellation Cetus brightens and fades dramatically every 11 months. At its brightest, it’s fairly easy to see. At its faintest, it’s visible only through a telescope. Because of that change, a 17th-century astronomer called the star Mira – from the Latin word for “wonderful.”
The star changes because it pulses in and out like a beating heart. Mira’s in the final stages of its red-giant phase of life. Its core is no longer producing nuclear reactions. Instead, it’s fusing hydrogen and helium in thin shells around the core.
Mira’s outer layers are puffed up by radiation from the shells. At the maximum, that inflates the star to about 400 times the diameter of the Sun. That’s also when its surface is coolest and faintest. As the outer layers cool, they fall inward, making the surface hotter and brighter. At minimum, the star is about 330 times the Sun’s diameter.
Each time it puffs up, Mira loses a little of the gas at its surface. Within the next million years or so, it’s likely to expel all the gas in its outer layers. That will leave only its hot but dead core – a white dwarf.
Astronomers have discovered thousands of stars like Mira. And many others will undergo the same phase, including the Sun – in about six billion years.
Mira climbs into view in the east by 8:30 or 9. But it’s in the “fading” part of its cycle, so you need a telescope to see it.
Script by Damond Benningfield
Australia