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Space News Update — January 25, 2019 —

Contents

In the News

Story 1: NASA's New Horizons space probe beams back sharpest image yet of Ultima

Thule

Story 2: One of Our Best Views of the Supermassive Black Hole at the Heart of the

Milky Way

Story 3: Making the Hubble's deepest images even deeper

Departments

The Night Sky

ISS Sighting Opportunities

Space Calendar

NASA-TV Highlights

Food for Thought

Space Image of the Week

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1. NASA's New Horizons space probe beams back sharpest image yet of Ultima

Thule

Now well clear of the sun on the far side of the solar system, NASA's New Horizons probeis downlinking recorded data from its New Year's Day flyby of Ultima Thule a billion miles past Pluto, including the sharpest view yet of the twin-lobe body.

In a brief release from the Johns Hopkins University Applied Physics Laboratory, researchers said the latest high-resolution image "is the clearest view yet of this remarkable, ancient object in the far reaches of the solar system."

The image was captured by the wide-angle Multi-color Visible Imaging Camera, or MVIC, taken at a distance of 4,200 miles from Ultima Thule just seven minutes before New Horizons made its closest approach. The image was stored aboard the spacecraft and transmitted back to Earth on Jan. 18-19.

"The oblique lighting of this image reveals new topographic details along the day/night boundary, or terminator, near the top," according to the APL release. "These details include numerous small pits up to about 0.4 miles in diameter. The large circular feature, about 4 miles across, on the smaller of the two lobes, also appears to be a deep depression.

"Not clear is whether these pits are impact craters or features resulting from other processes, such as 'collapse pits' or the ancient venting of volatile materials."

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The two lobes show "intriguing light and dark patterns of unknown origin, which may reveal clues about how this body was assembled during the formation of the solar system 4.5 billion years ago. One of the most striking of these is the bright 'collar' separating the two lobes."

Launched 13 years ago, New Horizons flew past Pluto in July 2015, racing by at a distance of 7,800 miles to collect the first close-up pictures and a wealth of data about the solar system's most famous dwarf planet.

Looking for another target beyond Pluto, the Hubble Space Telescope spotted a small body catalogued as 2014 MU69 that later was named Ultima Thule in a NASA naming contest. After the Pluto flyby was complete, New Horizons was ordered to change course, setting up the Jan. 1 Ultima Thule flyby.

The strange-looking body is one of the countless chunks of debris in the Kuiper Belt beyond Pluto thought to be left over from the original cloud of gas and dust that coalesced to form the solar system. It appears to be made up of two bodies that gently collided and stuck together in the distant past.

"This new image is starting to reveal differences in the geologic character of the two lobes of Ultima Thule, and is presenting us with new mysteries as well," Alan Stern, the New Horizons principal investigator, said in a statement.

"Over the next month there will be better color and better resolution images that we hope will help unravel the many mysteries of Ultima Thule."

Source: CBS News Return to Contents

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2. One of Our Best Views of the Supermassive Black Hole at the Heart of the Milky Way

One of Our Best Views of the Supermassive Black Hole at the Heart of the Milky Way

An almost unimaginably enormous black hole is situated at the heart of the Milky Way. It’s called a Supermassive Black Hole (SMBH), and astronomers think that almost all massive galaxies have one at their center. But of course, nobody’s ever seen one (sort of, more on that later): It’s all based on evidence other than direct observation.

The Milky Way’s SMBH is called Sagittarius A* (Sgr. A*) and it’s about 4 million times more massive than the Sun. Scientists know it’s there because we can observe the effect it has on matter that gets too close to it. Now, we have one of our best views yet of Sgr. A*, thanks to a team of scientists using a technique called interferometry.

As Sgr. A*’s powerful gravity draws gas and dust towards it, the gas and dust swirls around the hole. An enormous amount of energy is radiated somehow, which astronomers can see. But astronomers aren’t exactly certain what releases this energy. Is it coming from the swirling material? Or is it coming from jets of material shooting away from the hole?

“The source of the radiation from Sgr A* has been debated for decades,” says Michael Johnson of the Center for Astrophysics | Harvard and Smithsonian (CfA). “Some models predict that the radiation comes from the

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disk of material being swallowed by the black hole, while others attribute it to a jet of material shooting away from the black hole. Without a sharper view of the black hole, we can’t exclude either possibility.”

So understanding black holes means astronomers need to see more clearly into the region of the hole. But events at Sgr. A* are obscured by lumpy clouds of electrons between us and center of the galaxy. And these clouds blur and distort our view of the black hole.

A team of astronomers have succeeded in looking through these electron clouds to see more clearly what’s going on at Sgr. A*. The team is led by Radboud University PhD student Sara Issaoun, and to see into Sgr. A*’s neighborhood, they relied on a technique called Very Long Baseline Interferometry (VLBI).

The result? One of our clearest images yet of what goes on at our galaxy’s supermassive black hole.

Interferometry is the technique of harnessing multiple telescopes together to image a distant object more effectively. The further apart the ‘scopes are, the longer the baseline is and the larger the effective aperture is. With VLBI, used in this research, the individual telescopes span the globe, creating an enormous sort of virtual telescope.

But there have been other interferometers, and they didn’t see Sgr. A* this clearly. The team behind this study made one other advance in interferometry. They equipped the powerful ALMA (Atacama Large Millimeter Array) in Chile with new electronics, called a phasing system. That allowed ALMA, which is already an interferometer, to join a network of 12 other telescope called GMVA (Global 3mm VLBI Array). As the name says, GMVA is already a Very Long Baseline Interferometer. So joining GMVA with ALMA creates a sort of Super VLBI.

“ALMA itself is a collection of more than 50 radio dishes. The magic of the new ALMA Phasing System is to allow all these dishes to function as a single telescope, which has the sensitivity of a single dish more than 75 meters across. That sensitivity, and its location high in the Andes mountains, makes it perfect for this Sgr A* study,” says Shep Doeleman of the CfA, who was Principal Investigator of the ALMA Phasing Project.

“The breakthrough in image quality came from two factors,” explains Lindy Blackburn, a radio astronomer at the CfA. “By observing at high frequencies, the image corruption from interstellar material was less significant, and by adding ALMA, we doubled the resolving power of our instrument.”

So what have scientists learned from this innovation? How have these superior images helped them understand our supermassive black hole, Sgr. A*?

The new images show that the radiation from Sgr A* has a symmetrical morphology and is smaller than expected – it spans a mere 300 millionth of a degree. “This may indicate that the radio emission is produced in a disk of infalling gas rather than by a radio jet,” explains Issaoun, who tested computer simulations against the images. “However, that would make Sgr A* an exception compared to other radio-emitting black holes. The alternative could be that the radio jet is pointing almost directly at us.”

There’s a lot of debate around the energy radiated by Sgr. A*, and whether or not it’s from swirling, heated material in the accretion disc, or from jets of material directed away from the hole. It might depend on our vantage point.

Issaoun’s supervisor is Heino Falcke, Professor of Radio Astronomy at Radboud University. Falcke was surprised by this result, and last year, Falcke would have considered this new jet model implausible. But recently another set of researchers came to a similar conclusion using ESO’s Very Large Telescope

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Interferometer of optical telescopes and an independent technique. “Maybe this is true after all,” concludes Falcke, “and we are looking at this beast from a very special vantage point.”

Astronomers aren’t finished with Sgr. A* yet. They plan on getting better and better looks at the supermassive black hole. “The first observations of Sgr A* at 86 GHz date from 26 years ago, with only a handful of telescopes. Over the years, the quality of the data has improved steadily as more telescopes join,” says J. Anton Zensus, director of the Max Planck Institute for Radio Astronomy.

Next up is the Event Horizon Telescope.

The EHT is an international collaboration designed to investigate the immediate surroundings of a black hole. It’s not one telescope, but rather a linked system of radio telescopes across the globe all working together using interferometry. By measuring the electromagnetic energy from the region surrounding the black hole with multiple radio dishes at multiple locations, some of the properties of the source can be derived.

Astronomers spent a four year period using the EHT to study supermassive black hole Sgr. A*. That period ended in April 2017, but a team of 200 scientists and engineers is still working on the data. So far, they’ve released only a computer model image of what they hope to see.

Michael Johnson is optimistic. “If ALMA has the same success in joining the Event Horizon Telescope at even higher frequencies, then these new results show that interstellar scattering will not stop us from peering all the way down to the event horizon of the black hole.”

The team’s results were published in the Astrophysical Journal.

Source: Universe Today Return to Contents

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3. Making the Hubble's deepest images even deeper

It has taken researchers at the Instituto de Astrofísica de Canarias almost three years to produce the deepest image of the universe ever taken from space, by recovering a large quantity of "lost" light around the largest galaxies in the Hubble Ultra-Deep Field survey.

To produce the deepest image of the universe, a group of researchers from the Instituto de Astrofísica de Canarias (IAC) led by Alejandro S. Borlaff used original images from the Hubble Space Telescope (HST) taken over a region in the sky called the Hubble Ultra-Deep Field (HUDF). After improving the process of combining several images, the group was able to recover a large quantity of light from the outer zones of the largest galaxies in the HUDF. Recovering this light emitted by the stars in these outer zones was equivalent to recovering the light from a complete galaxy ("smeared out" over the whole field) and this missing light shows that some galaxies have diameters almost twice as large as previously measured.

The HUDF is the result of combining hundreds of images taken with the Wide Field Camera 3 (WFC3) of the HST during over 230 hours of observation which, in 2012, yielded the deepest image of the universe taken until then. But the method of combining the individual images was not ideally suited to detect faint extended objects. Borlaff says, "What we have done is to go back to the archive of the original images taken by the HST, and improve the process of combination, aiming at the best image quality not only for the more distant smaller galaxies, but also for the extended regions of the largest galaxies.

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The WFC3 was installed by astronauts in May 2009, when the Hubble had already been in space for 19 years. This presented a major challenge for the researchers because the complete instrument (telescope and camera) could not be tested on the ground, which made calibration more difficult. To overcome the problems, they analysed several thousand images of regions across the sky with the aim of improving the calibration of the telescope on orbit.

"The deepest image of the universe has been possible thanks to a striking improvement in the techniques of image processing which has been achieved in recent years, a field in which the group working in the IAC is at the forefront," says Borlaff.

Source: Phys.org Return to Contents

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The Night Sky Friday, January 25

• Right after dark, face east and look very high. The bright star there is Capella, the Goat Star. To the right of it, by a couple of finger-widths at arm's length, is a small, narrow triangle of 3rd and 4th magnitude stars known as "the Kids." They're not exactly eye-grabbing, but they form a never-forgotten asterism (informal star pattern) with Capella.

Saturday, January 26

• Orion is high in the southeast right after dark, and he stands highest due south around 10 p.m. Orion is the brightest of the 88 constellations, but his main pattern is surprisingly small compared to some of his dimmer neighbors. The biggest of these is Eridanus the Euphrates River just to his west, enormous but hard to trace. Dimmer Fornax the Furnace, to Eridanus's lower right, is almost as big as Orion! Even the main pattern of Lepus, the Hare cowering under Orion's feet, isn't much smaller than he is.

Sunday, January 27

• Last-quarter Moon (exact at 4:10 p.m. EST). The Moon rises around 1 a.m. tonight in dim Libra. As it climbs high, its curved edge points lower left to the spot on the horizon where Jupiter will rise around 4 a.m. and Venus about 15 minutes later (depending on your location).

Monday, January 28

• After dark the Great Square of Pegasus is sinking low in the west, tipped onto one corner. Look for it to the right of Mars. Meanwhile the Big Dipper is creeping up in the north-northeast, tipped up on its handle.

Tuesday, January 29

• In this dark-of-the-Moon period, use binoculars to get acquainted with the little asterisms a few degrees north of the main Hyades V pattern. (Zoom in on the View here.) I call two of these the Jumping Minnow and Dragonfly, imagining warm summer afternoons by a riverbank far separated from these icy winter nights.

Source: Sky & Telescope Return to Contents

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ISS Sighting Opportunities

For Denver: Date Visible Max Height Appears Disappears

Fri Jan 25, 6:16 PM 3 min 37° 28° above WNW 16° above NNE

Sat Jan 26, 7:00 PM 2 min 15° 10° above NW 15° above NNW

Sun Jan 27, 6:09 PM 4 min 20° 14° above WNW 10° above NNE

Mon Jan 28, 6:55 PM 1 min 11° 10° above NNW 11° above N

Tue Jan 29, 6:03 PM 3 min 13° 10° above NW 10° above NNE

Sighting information for other cities can be found at NASA’s Satellite Sighting Information NASA-TV Highlights (all times Eastern Daylight Time) Thursday, January 31, 1:15 p.m.: Canadian Space Agency PAO event with astronaut David Saint-Jacques from the Destiny Laboratory on the International Space Station with Kids Code Jeunesse in Vancouver, British Columbia.

Watch NASA TV on the Net by going to the NASA website. Return to Contents

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Space Calendar • Jan 25 - Comet C/2010 U3 (Boattini) At Opposition (7.930 AU) • Jan 25 - [Jan 18] Apollo Asteroid 2019 AJ13 Near-Earth Flyby (0.020 AU) • Jan 25 - Apollo Asteroid 2019 AG11 Near-Earth Flyby (0.022 AU) • Jan 25 - Apollo Asteroid 2019 AN12 Near-Earth Flyby (0.023 AU) • Jan 25 - Asteroid 4037 Ikeya Closest Approach To Earth (1.430 AU) • Jan 25 - Asteroid 12485 Jenniferharris Closest Approach To Earth (1.509 AU) • Jan 25 - Asteroid 13752 Grantstokes Closest Approach To Earth (1.893 AU) • Jan 25 - Asteroid 7028 Tachikawa Closest Approach To Earth (2.064 AU) • Jan 25 - Asteroid 8990 Compassion Closest Approach To Earth (2.079 AU) • Jan 25 - Apollo Asteroid 3671 Dionysus Closest Approach To Earth (2.306 AU) • Jan 25 - Plutino 208996 (2003 AZ84) At Opposition (43.494 AU) • Jan 25 - 15th Anniversary (2004), Mars Exploration Rover B (Opportunity), Mars Landing • Jan 25 - 25th Anniversary (1994), Clementine Launch (USA Moon Orbiter) • Jan 26 - Comet 98P/Takamizawa At Opposition (3.943 AU) • Jan 26 - Apollo Asteroid 2019 AA10 Near-Earth Flyby (0.014 AU) • Jan 26 - Apollo Asteroid 136617 (1994 CC) (2 Moons) Closest Approach To Earth (1.319 AU) • Jan 26 - Asteroid 4444 Escher Closest Approach To Earth (1.653 AU) • Jan 26 - Asteroid 224 Oceana Closest Approach To Earth (1.767 AU) • Jan 26 - Asteroid 85185 Lederman Closest Approach To Earth (1.803 AU) • Jan 27 - Comet 223P/Skiff Perihelion (2.431 AU) • Jan 27 - Asteroid 727 Nipponia Closest Approach To Earth (1.513 AU) • Jan 27 - Asteroid 11947 Kimclijsters Closest Approach To Earth (2.866 AU) • Jan 27 - Isaac Roberts' 190th Birthday (1829) • Jan 28 - Comet C/2010 U3 (Boattini) Closest Approach To Earth (7.929 AU) • Jan 28 - Comet 1P/Halley At Opposition (33.845 AU) • Jan 28 - Aten Asteroid 2019 AP11 Near-Earth Flyby (0.026 AU) • Jan 28 - Asteroid 32096 Puckett Closest Approach To Earth (1.949 AU) • Jan 28 - Asteroid 4356 Marathon Closest Approach To Earth (2.212 AU) • Jan 28 - Asteroid 10792 Ecuador Closest Approach To Earth (2.340 AU) • Jan 28 - Asteroid 1134 Kepler Closest Approach To Earth (2.666 AU) • Jan 28 - Donald Parker's 80th Birthday (1939) • Jan 28 - Lucien d'Azambuja's 135th Birthday (1884) • Jan 28 - Auguste Piccard's 135th Birthday (1884) • Jan 28 - Jean Felix Piccard's 135th Birthday (1884) • Jan 29 - Comet 360P/WISE At Opposition (3.151 AU) • Jan 29 - Aten Asteroid 2019 AN11 Near-Earth Flyby (0.033 AU) • Jan 29 - Aten Asteroid 2013 CW32 Near-Earth Flyby (0.036 AU) • Jan 29 - Asteroid 6318 Cronkite Closest Approach To Earth (1.037 AU) • Jan 29 - Asteroid 5945 Roachapproach Closest Approach To Earth (1.560 AU) • Jan 29 - Asteroid 5515 Naderi Closest Approach To Earth (1.663 AU)

Source: JPL Space Calendar Return to Contents

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Food for Thought

We May Have Found Earth's Oldest Known Rock. It Was on The Moon

Earth's oldest known rock may have been found, in the last place anyone would have thought to look for it: in samples of rock from the Moon, brought back home to Earth by Apollo 14 astronauts in 1971.

We're not talking about a "Moon was once part of Earth" rock (that's just one hypothesis for the Moon's origin, anyway).

Nope. According to an international team of scientists, there's evidence the rock was terrestrial in origin - it's a 2-gram piece of quartz, feldspar, and zircon embedded in a larger chunk of rock called Big Bertha - minerals that are rare on the Moon, but really common here on Earth.

And chemical analysis has revealed that it formed in an oxidised system like Earth's, in Earth-like temperatures, rather than the Moon's temperature conditions. If it had formed on the Moon, that would require conditions never before inferred from lunar samples.

So how the heck did it get there, then?

According to the scientists, it was launched off Earth about 4 billion years ago when an asteroid or comet slammed into our young, roughly 540-million-year-old planet, sending rock fragments flying off into space.

Because the Moon was much closer to Earth at that point - about three times closer than it is now - it was in a better position for pieces of this debris to end up there.

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"It is an extraordinary find that helps paint a better picture of early Earth and the bombardment that modified our planet during the dawn of life," said earth and planetary scientist David Kring of the Lunar and Planetary Institute.

(Kring had challenged the team, led by Jeremy Bellucci of the Swedish Museum of Natural History and Alexander Nemchin of Curtin University in Australia, to find a piece of Earth on the Moon. Guess they won.)

The team was able to perform more detailed analyses on the rock. The inclusion of zircon was particularly useful, since zircon contains uranium, the known half-life of which allows for accurate dating.

The formation of the rock was therefore dated to about 4 to 4.1 billion years ago. It formed under the planet's surface at a depth of about 20 kilometres (12.4 miles), where it remained until a violent impact hurled it into space.

From there, it made its way to the Moon, where further impact events probably partially melted and buried it around 3.9 billion years ago.

It was then returned to the surface around 26 million years ago, during the impact event that produced the Cone Crater - where it remained until Big Bertha was collected by Apollo 14 astronauts just a few decades ago.

It's possible that the fragment did indeed form on the Moon, but the conditions for that would be unlike anything we've seen on the satellite. It would've had to have formed 30 to 70 kilometres below the surface, in an "unusually oxidising magmatic environment" with oxygen levels much higher than those in the lunar mantle 4 billion years ago.

By contrast, the terrestrial conditions seem much more likely - even if it seems a spectacular coincidence that this tiny fragment was later returned to Earth.

But it might not be so hard to verify. If one fragment could be found, there should be others, and studies of other lunar samples may locate them. In addition, with NASA's plan to return humans to the Moon, there could be future opportunities to collect even more samples. The team's research has been published in Earth and Planetary Science Letters.

Source: Science Alert Return to Contents

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Space Image of the Week

Moon Struck Image Credit & Copyright: Petr Horálek

Explanation: Craters produced by ancient impacts on the airless Moon have long been a familiar sight. But only since the 1990s have observers began to regularly record and study optical flashes on the lunar surface, likely explosions resulting from impacting meteoroids. Of course, the flashes are difficult to see against a bright, sunlit lunar surface. But during the January 21 total eclipse many imagers serendipitously captured a meteoroid impact flash against the dim red Moon. Found while examining images taken shortly before the total eclipse phase began, the flash is indicated in the inset above, near the Moon's darkened western limb. Estimates based on the flash duration recorded by the Moon Impact Detection and Analysis System (MIDAS) telescopes in southern Spain indicate the impactor's mass was about 10 kilograms and created a crater between seven and ten meters in diameter.

Source: APOD Return to Contents