Cool astronomy photos

[Witness]

Never noticed these stripes on the sun (look quite like the clouds of Venus in UV).

Another, slower, recent one:

Link: https://twitter.com/esa/status/1072798121162366976

[Rob Lister]

Here’s why China’s launch to the far side of the Moon is a big deal

This may be aprecursor for a space race back to the Moon.

Funking tabloid media. What's the point of the instigation? Besides, it's going to be hard for them to win a race that was already won 50 years before they even mosied up to the starting line.

But I applaud their endeavor to further explore.

If successful, this mission will carry out several lines of important scientific research on the still somewhat unknown far unlanded upon side of the Moon.

A nit worth picking?

China has not said when it will attempt to land on the far side of the Moon, ... Chang'e-4 will have to link up with the Queqiao relay spacecraft, which will have line-of-sight communications with both the lander, which is expected to set down in the South Pole-Aitken Basin, as well as Earth.

That's pretty cool. Of course, there will be blackout periods on every orbit but I figure with an elliptical enough orbit, maybe less than 10% of the orbit. It would be fun to work that out exactly ... but also too fucking hard.

[Witness]

Funking tabloid media.

Wholeheartedly agree!

[Witness]

For our resident astronomers:

How to see 2018’s brightest comet

Have you heard about comet 46P/Wirtanen? It passes closest to the sun on December 12, 2018, and closest to Earth just a few days later, on December 16. Comet Wirtanen is the brightest comet in the night sky now; it’s the brightest comet of 2018. Although theoretically visible to the eye now, this comet is not easily visible to the eye.

Details & links: https://earthsky.org/space/46p-wirtanen ... e-dec-2018

[Anaxagoras]

Witness posted a GIF of this a couple pages back, but here's a higher-res still image:

This mosaic image, composed of 12 Polycam images collected on December 2, 2018, and provided by NASA, shows the asteroid Bennu. NASA's first look at a tiny asteroid shows that the space rock is more moist and studded with boulders than originally thought. On December 10, scientists released the first morsels of data collected since their spacecraft Osiris-Rex hooked up last week with the asteroid, which is only about three blocks wide and weighs about 80 million tons. Bennu regularly crosses Earth's orbit and will come perilously close to Earth in about 150 years.

More photos here

[Bruce]

When I think of asteroids, I don't think "moist", but thanks to this article, I will now.

[Bruce]

Name three things that are moist.

1. Disposable towellets
2. Good chocolate cake
3. Asteroids

Thanks NASA.

[Anaxagoras]

Can't please everyone. But remember that much of the water on earth came from asteroids and comets that bombarded the planet in the early days. Or at least that's how some theories go I think. Too lazy to look it up right now.

[Witness]

When I think of asteroids, I don't think "moist", but thanks to this article, I will now.

Always complainin'. Don't you see that it's a giant, crunchy, awesome cookie?

[Bruce]

Can't please everyone. But remember that much of the water on earth came from asteroids and comets that bombarded the planet in the early days. Or at least that's how some theories go I think. Too lazy to look it up right now.

That theory lost some popularity when we landed a probe on that comet a few years ago. The isotopic ratios in the hydrogen and oxygen didn't match those on earth. I don't know why that matters because comets get bombarded by radiation for billions of years that we are shielded from on earth due to our magnetic field, so of course the isotopic ratios are going to be different.

[Witness]

That theory lost some popularity when we landed a probe on that comet a few years ago. The isotopic ratios in the hydrogen and oxygen didn't match those on earth. I don't know why that matters because comets get bombarded by radiation for billions of years that we are shielded from on earth due to our magnetic field, so of course the isotopic ratios are going to be different.

I wonder, is there really a spallation process producing hydrogen (i. e. protons) or one of its isotopes?

As for the different isotopic contents in the Solar System and their (multiple!) causes, there is a long discussion thread here: https://www.researchgate.net/post/What_ ... lar_System

I extract the first post:

Christian Vollmer
University of Münster

Isotopic anomalies in solar system objects can be due to 1) nucleosynthetic effects, i.e., material that has been synthesized in other stars and preserved in presolar stardust grains, 2) molecular cloud fractionation effects at very low temperatures that have been preserved in very primitive organic matter as H-C-N anomalies, 3) anomalies in short-lived radionuclides like 26Al that are due to their different decay at different times after solar system formation, 4) cosmogenic effects due to exposure to the galactic high energy environment (e.g., spallation reactions), 5) Anomalies in oxygen isotopes that are due to CO self shielding under UV irradiation of the young Sun (mass-independent fractionation), and 6) mass dependent fractionation. The question is to what composition you want to refer your anomalies. For instance, the Earth and most meteoritic materials are isotopically anomalous in N and O with respect to the Sun (see results by the GENESIS mission)!

---

Now for an astronomical seasonal snowman:

Sometimes it's all about perspective. This very convincing image of a conjoined moon masquerading as a snowman is actually two separate Saturnian moons – Dione and Rhea – taken from such an angle by the international Cassini spacecraft that they appear as one.

Dione (top) was actually closer to the spacecraft at the time the image was taken, at around 1.1 million kilometres, compared to Rhea (bottom) which was around 1.6 million kilometres from Cassini. Dione has a diameter of 1123 kilometres and Rhea is larger with a diameter of 1528 kilometres, but they appear to have a similar size in this image due to the difference in distance.

The moons also orbit Saturn at different distances: Dione lies at roughly the same distance as the Moon from the Earth and orbits around the ringed planet in just 2.7 days, while Rhea sits slightly further away and has a 4.5 day orbit.

https://phys.org/news/2018-12-image-dione-rhea.html

[Bruce]

Thanks. Cool stuff.

I still think water came from comets. However, it's not like these comets land, melted, and gave us oceans. It was probably more like millions of years of explosive impacts that blasted water vapor into space, which was then slowly pulled back into earth's orbit.

[Witness]

NASA's InSight spacecraft, its heat shield and its parachute were imaged on Dec. 6 and 11 by the HiRISE camera onboard NASA's Mars Reconnaissance Orbiter.

On Nov. 26, NASA's InSight mission knew the spacecraft touched down within an 81-mile-long (130-kilometer-long) landing ellipse on Mars. Now, the team has pinpointed InSight's exact location using images from HiRISE, a powerful camera onboard another NASA spacecraft, Mars Reconnaissance Orbiter (MRO).

https://www.sciencedaily.com/releases/2 ... 204347.htm

There's no privacy anywhere anymore.

[Witness]

No spectacular pictures, but:

It’s the Solar System’s Most Distant Object. Astronomers Named It Farout.

Orbiting 11 billion miles from the sun, this tiny world offers additional clues in the search for the proposed Planet Nine.

Astronomers have discovered a far-out world circling the sun.

How far out? It’s so far out that the discoverers nicknamed it “Farout.” All they can see is a pinkish dot of light in the night sky, but that is enough to infer that they are looking at a 300-mile ice ball orbiting more than 11 billion miles from the sun — more than three times as far out as Pluto, and the farthest object ever observed within the solar system.

It is the latest revelation in a distant region that was once expected to be empty, and studying its trajectory may help point to an as-yet-unseen ninth planet circling the sun far beyond Neptune.

On Monday, the International Astronomical Union’s Minor Planet Center announced the discovery and gave this object the designation 2018 VG18.

“Last month, we came across it moving very, very slow,” said Scott S. Sheppard of the Carnegie Institution for Science, one of the discoverers of VG18. “Immediately we knew it was an interesting object.”

https://www.nytimes.com/2018/12/17/scie ... ystem.html (more details)

Farout was observed by the Subaru Telescope, on Mauna Kea Observatory in Hawaii, on Nov. 10.In the hour between exposures, the object moved relative to the background stars and galaxies.
CreditScott S. Sheppard and David Tholen/Carnegie Institution for Science

[Witness]

Stunning Photos Show Huge Crater on Mars Absolutely Brimming With Water Ice

The Mars orbiter has obtained a stunning view of a feature called the Korolev crater, an 81.4-kilometre (50.6-mile) diameter crater just south of the Olympia Undae dunes circling the northern polar cap. The crater is filled almost to the brim with pristine ice year-round.

Like Earth, Mars does have seasons. And like Earth, the warmer seasons result in receding ice. But Korolev crater, created by a massive impact sometime in Mars's distant past, and named for Soviet rocket engineer Sergei Korolev, is a bit of an oddball.

It's a type of geological feature known as a 'cold trap', and that's exactly what it sounds like. The floor of the crater is very deep, just over 2 kilometres (1.2 miles) below the rim. From the floor of the crater rises a dome of water ice, 1.8 km (1.1 miles) thick and up to 60 km (37.3 miles) in diameter.

In volume, it contains around 2,200 cubic kilometres (528 cubic miles) of ice (although an unknown proportion of it is probably Mars dust).

https://www.sciencealert.com/a-mars-sat ... artian-ice

[Grammatron]

"Photos"

[sparks]

You're making a point?

[Witness]

For our resident astronomers:

How to see 2018’s brightest comet

Technical details: https://old.reddit.com/r/Astronomy/comm ... comet_46p/
Timelapse: https://www.instagram.com/p/BriLUbzDN0I/

[Witness]

Something like this has already been posted, but it still impresses me – if only Andromeda were brighter:





Details: https://waitbutwhy.com/2014/06/andromed ... d-see.html

[Witness]

Holiday asteroid imaged with NASA radar



The December 2018 close approach by the large, near-Earth asteroid 2003 SD220 has provided astronomers an outstanding opportunity to obtain detailed radar images of the surface and shape of the object and to improve the understanding of its orbit.

The radar images reveal an asteroid with a length of at least one mile (1.6 kilometers) and a shape similar to that of the exposed portion of a hippopotamus wading in a river. They were obtained Dec. 15-17 by coordinating the observations with NASA's 230-foot (70-meter) antenna at the Goldstone Deep Space Communications Complex in California, the National Science Foundation's 330-foot (100-meter) Green Bank Telescope in West Virginia and the Arecibo Observatory's 1,000-foot (305-meter) antenna in Puerto Rico.

The Green Bank Telescope was the receiver for the powerful microwave signals transmitted by either Goldstone or the NASA-funded Arecibo planetary radar in what is known as a "bistatic radar configuration." Using one telescope to transmit and another to receive can yield considerably more detail than would one telescope, and it is an invaluable technique to obtain radar images of closely approaching, slowly rotating asteroids like this one.

"The radar images achieve an unprecedented level of detail and are comparable to those obtained from a spacecraft flyby," said Lance Benner of the Jet Propulsion Laboratory in Pasadena, California, and the scientist leading the observations from Goldstone. "The most conspicuous surface feature is a prominent ridge that appears to wrap partway around the asteroid near one end. The ridge extends about 330 feet [100 meters] above the surrounding terrain. Numerous small bright spots are visible in the data and may be reflections from boulders. The images also show a cluster of dark, circular features near the right edge that may be craters."

The images confirm what was seen in earlier "light curve" measurements of sunlight reflected from the asteroid and from earlier radar images by Arecibo: 2003 SD220 has an extremely slow rotation period of roughly 12 days. It also has what seems to be a complex rotation somewhat analogous to a poorly thrown football. Known as "non-principal axis" rotation, it is uncommon among near-Earth asteroids, most of which spin about their shortest axis.

With resolutions as fine as 12 feet (3.7 meters) per pixel, the detail of these images is 20 times finer than that obtained during the asteroid's previous close approach to Earth three years ago, which was at a greater distance. The new radar data will provide important constraints on the density distribution of the asteroid's interior -- information that is available on very few near-Earth asteroids.

https://www.sciencedaily.com/releases/2 ... 162221.htm

[Anaxagoras]

Clearly fake!!!11!

[Witness]

Clearly fake!!!11!

Indeed. Fisheye lens to hide the flatness of the Earth!

---

If you have time on your hands:

[Witness]

How to spend New Year’s Eve with NASA watching New Horizons’ flyby of Ultima Thule

This New Year's, you can go to a boring old bar like everyone else, or you can celebrate the dawning of another year by watching NASA's New Horizons spacecraft make history.

At 12:33 a.m. EST on January 1, the craft will fly within 2,200 miles (3,540 km) of 2014 MU69, more commonly known as Ultima Thule, an object far out beyond Pluto in the Kuiper Belt. NASA will be broadcasting the event on NASA TV and providing updates through their social media channels. You can find more details through the New Horizons mission page.

This will be the farthest object ever visited by a spacecraft, and New Horizons will come three times closer to Ultima Thule than it came to Pluto in 2015. The object is around 19 miles (30km) in diameter, shaped something like a peanut and is likely red in color. Ultima Thule orbits the sun about once every 295 years, and has likely been almost undisturbed since it was formed during the early days of the solar system, making it an exciting target for astronomers.

The flyby will take place about four billion miles (6.6 billion km) from Earth. Because of this, radio signals carrying information from New Horizons to NASA's Deep Space Network will take more than six hours to make the trip, and we'll have to wait just a little bit longer to see Ultima Thule.
[…]
Johns Hopkins University Applied Physics Laboratory will provide a live webcast of the event which can be viewed here.

http://www.astronomy.com/news/2018/12/h ... tima-thule

[Anaxagoras]

Link to discussion or higher-res version

[Witness]

[Anaxagoras]

[Bruce]

Space gourd

[Witness]

Chang’e 4 successfully landed on the far side of the moon.

[Rob Lister]

Chang’e 4 successfully landed on the far side of the moon.

https://www.cnbc.com/2019/01/02/china-l ... -moon.html

Looks surprisingly like a pretzel or hotdog street vendor cart.



In the earlier post, I wondered what the orbit of the relay satellite would be. I figured a very elliptical orbit to minimize black-out time. Wow was I way off track.



Those clever fuckers.

[Anaxagoras]

Chang’e 4 successfully landed on the far side of the moon.

First photos published:



https://www.businessinsider.com/photos- ... ing-2019-1

[Witness]

[Anaxagoras]

https://gfycat.com/HospitableObedientCurassow

[Witness]

And then it will capsize in the crater ahead, I presume.

[Anaxagoras]

I wonder if it can go into the crater safely, and if it does, whether it can get back out again.

I suspect they won't take that risk. At least not yet anyway.

But gravity being so light there, I would imagine it would be possible. Going up a slope would be easier than going up a similar slope under Earth gravity.

[Rob Lister]

But gravity being so light there, I would imagine it would be possible. Going up a slope would be easier than going up a similar slope under Earth gravity.

But only 16% the traction. And those wheels ain't exactly snow tires.

[Anaxagoras]

But gravity being so light there, I would imagine it would be possible. Going up a slope would be easier than going up a similar slope under Earth gravity.

But only 16% the traction. And those wheels ain't exactly snow tires.

True, and although the weight would be less, the mass is unchanged.

The Apollo astronauts had a moon buggy. I wonder if it even got stuck and needed someone to get out and push.

[Witness]

Hubble takes gigantic image of the Triangulum Galaxy

This new image of the Triangulum Galaxy—also known as Messier 33 or NGC 598—has a staggering 665 million pixels and showcases the central region of the galaxy and its inner spiral arms. To stitch together this gigantic mosaic, Hubble's Advanced Camera for Surveys needed to create 54 separate images.

Under excellent dark-sky conditions, the Triangulum Galaxy can be seen with the naked eye as a faint, blurry object in the constellation of Triangulum (the Triangle), where its ethereal glow is an exciting target for amateur astronomers.

At only three million light-years from Earth, the Triangulum Galaxy is a notable member of the Local Group—it is the group's third-largest galaxy, but also the smallest spiral galaxy in the group. It measures only about 60 000 light-years across, compared to the 200 000 light-years of the Andromeda Galaxy; the Milky Way lies between these extremes at about 100 000 light-years in diameter.

The Triangulum Galaxy is not only surpassed in size by the other two spirals, but by the multitude of stars they contain. The Triangulum Galaxy has at least an order of magnitude less stars than the Milky Way and two orders of magnitude less than Andromeda. These numbers are hard to grasp when already in this image 10 to 15 million individual stars are visible.

https://phys.org/news/2019-01-hubble-gi ... alaxy.html

[Witness]

https://i.imgur.com/2HAQexm.gifv

Sidereal day length and axial tilt for the 8 largest planets in our Solar System.

[Witness]

The Chinese rover has awakened and taken a picture of the lander (he's mirrored next to the flag):


https://gbtimes.com/yutu-2-rover-reawak ... objectives

I'm astonished by the whitish stones looking out of the regolith. Don't remember anything similar on the other face.

[sparks]

Perhaps it comes down to better camera technology?