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It’s every space mission’s nightmare: losing contact with the spacecraft. In the best case, you recover it right away. Worst case, you never hear from your hardware again. On July 21, controllers lost contact with Voyager 2, out in the depths of space. Now they’re waiting for a reset to catch Voyager 2’s next message when it “phones home”.

So, what happened? The spacecraft, which is nearly 20 billion kilometers away, seems to be doing fine. It’s probably sending all kinds of communications back to Earth. But, the stream of data is bounding off into space instead of linking up with the Deep Space network. That’s because a series of planned commands to Voyager 2 inadvertently caused the spacecraft to point its antenna 2 degrees away from Earth. Essentially, Voyager 2 and Earth are not in communication. They’re “talking past” each other.

This artist's concept depicts one of NASA's Voyager spacecraft, including its high-gain antenna. Voyager 2 is out of communications until October. Credit: NASA/JPL-Caltech
This artist’s concept depicts one of NASA’s Voyager spacecraft, including its high-gain antenna. The cosmic ray subsystem is highlighted, too. Voyager 2 is out of communications until October. Credit: NASA/JPL-Caltech

Regaining Contact with Voyager 2

All is not lost. Yet. That’s because the spacecraft is programmed to reset its orientation several times a year to keep the antenna pointed toward Earth. The next reset isn’t for several months—on October 15th. Until then, Voyager 2 is speeding along on its planned trajectory. If all goes well, the control team should hear from the spacecraft again on October 15th. At this point, they’re characterizing this loss of signal as a temporary communications pause. There’s nothing to indicate any other problems with Voyager 2, beyond the mistaken commands.

The spacecraft is equipped with a high-gain antenna measuring 3.7 meters across. It communicates with the Deep Space Network via the S band (13 cm wavelength) channel as well as in the X band (3.6 cm wavelength). At its current distance, the spacecraft’s signals take about 17.5 hours to get back to Earth. That time increases as the spacecraft gets farther away.

Glorious History

Currently, Voyager 2 and its twin Voyager 1 are exploring space beyond the solar system. They launched in 1977 and for the past decades, they’ve made huge discovieres at planets and the outermost bounds of the heliosphere. Their images and data opened up a whole new way of looking at the outer solar system.

Now, they’re in the Voyager Interstellar Mission phase, where their data helps characterize the “limits” of the solar system lie and where deep space begins. Voyager 2 probably entered interstellar space a few years ago, although it still reports on conditions at the “edge” of the solar system. Interestingly, while Voyager 2 is out of communications with Earth, Voyager 1 is still talking with the Deep Space Network. It’s about 24 billion kilometers from Earth.

This illustration shows the position of NASA’s Voyager 1 and Voyager 2 probes, outside of the heliosphere, a protective bubble created by the Sun that extends well past the orbit of Pluto. Voyager 1 exited the heliosphere in August 2012. Voyager 2 exited at a different location in November 2018. Credit: NASA/JPL-Caltech

Ultimately, they’re headed out on two very different trajectories through the stars. They have enough power to operate for a few more years (2025 or thereabouts) to send back information to Earth about their environments. Engineers on the project have figured out a way to extend spacecraft power for perhaps a couple more years by tapping some specific onboard reserves. Eventually, however, the spacecraft will fall silent as their power supplies run out. This current outage on Voyager 2 is giving mission engineers an early taste of what that experience will be like, after “talking” with these distant spacecraft for nearly five decades.

For More Information

Mission Update: Voyager 2 Communications Pause
Voyagers Mission Status

The post Oops. NASA Accidentally Points Voyager 2’s Antenna Away from Earth, Temporarily Losing Contact appeared first on Universe Today.

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Are Titan’s Dunes Made of Comet Dust?

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A new theory suggests that Titan’s majestic dune fields may be have come from outer space. Researchers had always assumed that the sand making up Titan’s dunes was locally made, through erosion or condensed from atmospheric hydrocarbons. But researchers from the University of Colorado want to know: Could it have come from comets?

The dunes of Titan

When the Cassini spacecraft arrived in orbit around Saturn, nobody had ever seen beneath the thick soupy atmosphere of Titan. So when it dropped the Huygens lander, and began probing Titan with cloud-penetrating radar, scientists were surprised to learn that Titan has a very earth-like appearance. It has a thick nitrogen atmosphere, rain, rivers, oceans and massive dune fields. But unlike the dunes of Earth’s sandy deserts in Namibia and southern Arabia, Titan’s dunes are enormous, and fill massive fields covering more than an eighth of the giant moon’s surface. These dunes are about 100 meters tall, 1 to 2 km wide at the base, and can stretch for hundreds of kilometers in length.

Dunes on Earth are made from sand, which is blown by the wind and heaped into drifts. Individual sand particles are nudge and blown by the wind with enough force to make them bounce and scatter, in a process called saltation. If the particles don’t bounce, then they cannot pile up on top of each other, but if the wind is able to lift them off the ground completely then they simply blow away. Saltation depends on the size and mass of the sand particles and the strength of the wind, but also needs the particles to be dry so that they can move freely without sticking together.

Titan’s geology

Titan is the second largest moon in the entire Solar System, beaten only by Ganymede, orbiting Jupiter. It is Saturn’s largest moon, and very old. Unlike most of Saturn’s moon, which were captured over time, Titan would have formed together with Saturn billions of years ago. Despite having so many features in common with Earth, it is a very different place. It is so intensely cold that, instead of water, its rain and rivers are made from liquid hydrocarbons like methane. Water, on the other hand, is frozen into hard ice; rocks on Titan are made from water ice, instead of granite and basalt, and Titan’s equivalent of lava and magma are made from liquid water and ammonia.

This means that sand on Titan is not made from silica eroded from larger rocks, since those materials are not found on the surface. One popular theory is that it could instead be made from ice. When liquid methane rains and flows, it could erode the water-ice bedrock, grinding chunks together to a sand of ice grains. An alternative idea is that the sand particles are instead made from tholins. These are found all over the colder regions of the Solar System, where cold hydrocarbons in comets or the outer atmospheres of planets and moons react with ultraviolet light from the Sun to create complex compounds. Tholins formed in the dry atmosphere of Titan could clump together with static electricity to form small grains of soot that then settle to the ground, creating both dust and sand.

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Comet 109P/Swift-Tuttle captured during its last pass by Earth on Nov. 1, 1992. Credit: Gerald Rhemann

What do comets have to do with this?

But a paper presented at this year’s Lunar and Planetary Science Conference (LPSC) suggests a new idea: What if the sand came from comets? Comets, as we know, are made from materials left over from the creation of the Solar System. Most of the primordial gas and dust that collapsed from an ancient nebula to form the Solar System would have ended up in the Sun, with the bulk of the remains forming the planets. But this still would still have left a lot of material floating free, and some of that would have gradually coalesced into lumps of dust and ices, which we see today as comets. When comets are nudged into elliptical orbits and pass through the inner Solar System, some of their ice heats up and sublimates into gas which blows out, carrying dust with it. This dust is scattered throughout the Solar System, concentrated along the various comet’s orbits. Individual grains often collide with the Earth, which we see as meteors, burning high in our atmosphere. Recent surveys in Antarctic ice

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The Milky Way’s Most Massive Stellar Black Hole is Only 2,000 Light Years Away

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Astronomers have found the largest stellar mass black hole in the Milky Way so far. At 33 solar masses, it dwarfs the previous record-holder, Cygnus X-1, which has only 21 solar masses. Most stellar mass black holes have about 10 solar masses, making the new one—Gaia BH3—a true giant.

Supermassive black holes (SMBH) like Sagittarius A Star at the heart of the Milky Way capture most of our black hole attention. Those behemoths can have billions of solar masses and have enormous influence on their host galaxies.

But stellar-mass holes are different. Unlike SMBHs that grow massive through mergers with other black holes, stellar black holes result from massive stars exploding as supernovae. SMBHs are always found in the center of a massive galaxy, but stellar black holes can be hidden anywhere.

“This is the kind of discovery you make once in your research life.”

Pasquale Panuzzo, National Centre for Scientific Research (CNRS) at the Observatoire de Paris

Astronomers found BH3 in data from the ESA’s Gaia spacecraft. It’s Gaia’s third stellar black hole. BH3 has a stellar companion, and the black hole’s 33 combined solar masses tugged on its aged, metal-poor companion. The star’s tell-tale wobbling betrayed BH3’s presence. At only 2,000 light-years away, BH3 is awfully close in cosmic terms.

Astronomers have found the most massive stellar black hole in our galaxy, thanks to the wobbling motion it induces on a companion star. This artist's impression shows the star's orbits and the black hole, dubbed Gaia BH3, around their common centre of mass. The European Space Agency's Gaia mission measured this wobbling over several years. Image Credit: ESO/L. Calçada
Astronomers have found the most massive stellar black hole in our galaxy, thanks to the wobbling motion it induces on a companion star. This artist’s impression shows the star’s orbits and the black hole, dubbed Gaia BH3, around their common centre of mass. The European Space Agency’s Gaia mission measured this wobbling over several years. Image Credit: ESO/L. Calçada

A new research letter in Astronomy and Astrophysics presented the discovery. Its title is “Discovery of a dormant 33 solar-mass black hole in pre-release Gaia astrometry.” The lead author is Pasquale Panuzzo, an astronomer from the National Centre for Scientific Research (CNRS) at the Observatoire de Paris.

“No one was expecting to find a high-mass black hole lurking nearby, undetected so far,” said Panuzzo. “This is the kind of discovery you make once in your research life.”

This black hole is remarkable for its considerable mass. Researchers have found stellar black holes with similar masses, but always in other galaxies. The size is confounding, but astrophysicists have pieced together how they may become so massive.

They could result from the collapse of metal-poor stars. These stars are composed almost entirely of hydrogen and helium, the primordial elements. Scientists think these stars lose less mass over their lifetimes of fusion than other stars. They retain more mass, so they collapse into more massive black holes. This idea is based on theory; there’s no direct evidence.

But BH3 could change that.

Binary stars tend to form together and have the same metallicity. Follow-up observations showed that BH3’s companion star is likely a remnant of a globular cluster that the Milky Way absorbed more than eight billion years ago. Since binary stars tend to have the same metallicity, this metal-poor companion bolsters the idea that low-metallicity stars can retain more mass and form larger stellar black holes. This is the first evidence supporting the idea that ancient and metal-poor massive stars collapse into massive black holes. It also supports the idea that these early stars may have evolved differently than modern stars of similar masses.

But there’s another interpretation.

Supernova ESO II edited 1Did you miss our previous article…
https://mansbrand.com/the-solar-eclipse-like-weve-never-seen-it-before/

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The Solar Eclipse Like We’ve Never Seen it Before

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You had to be in the right part of North America to get a great view of the recent solar eclipse. But a particular telescope may have had the most unique view of all. Even though that telescope is in Hawaii and only experienced a partial eclipse, its images are interesting.

You had to be in the right part of North America to get a great view of the recent eclipse. Image Credit: DKIST/NSO/NSF/AURA
You had to be in the right part of North America to get a great view of the recent eclipse. Image Credit: DKIST/NSO/NSF/AURA

The Daniel K. Inouye Solar Telescope (DKIST) is at the Haleakala Observatory in Hawaii. With its four-meter mirror, it’s the largest solar telescope in the world. It observes in visible to near-infrared light, and its sole target is the Sun. It can see features on the Sun’s surface as small as 20 km (12 miles.) It began science operations in February 2022, and its primary objective is to study the Sun’s magnetic fields.

This is a collage of solar images captured by the Inouye Solar Telescope. Images include sunspots and quiet regions of the Sun, known as convection cells. (Credit: NSF/AURA/NSO)
This is a collage of solar images captured by the Inouye Solar Telescope. Images include sunspots and quiet regions of the Sun, known as convection cells. (Credit: NSF/AURA/NSO)

Though seeing conditions weren’t perfect during the eclipse and the eclipse was only partial when viewed from Hawaii, the telescope still gathered enough data to create a movie of the Moon passing in front of the Sun. The bumps on the Moon’s dark edge are lunar mountains.

via GIPHY

“The team’s primary mission during Maui’s partial eclipse was to acquire data that allows the characterization of the Inouye’s optical system and instrumentation,” shares National Solar Observatory scientist Dr. Friedrich Woeger.

The Moon plays a critical role in measuring the telescope’s performance. Its edge is well-known and as a dark object in front of the Sun, it acts as a unique tool to measure the Inouye telescope’s performance and to understand the data it collects. Since the telescope has to correct for Earth’s turbulent atmosphere with adaptive optics, the Moon’s known qualities help researchers work with the telescope’s optical elements.

The Daniel Inouye Solar Telescope at the Haleakala Observatory on the Hawaiian island of Maui. Image Credit: DKIST/NSO
The Daniel Inouye Solar Telescope at the Haleakala Observatory on the Hawaiian island of Maui. Image Credit: DKIST/NSO

“With the Inouye’s high order adaptive optics system operating, the blurring due to the Earth’s atmosphere was greatly reduced, allowing for extremely high spatial resolution images of the moving lunar edge,” said Woeger.
Did you miss our previous article…
https://mansbrand.com/the-milky-ways-history-is-written-in-streams-of-stars/

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