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Jupiter and Saturn in rare celestial ‘Great Conjunction’ – Al Jazeera English

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Solar system’s two biggest planets come within planetary kissing range, an intimacy that will not occur again until 2080.

The solar system’s two biggest planets, Jupiter and Saturn, came within planetary kissing range in Monday’s evening sky, an intimacy that will not occur again until 2080.

This “Great Conjunction”, as it is known to astronomers, occurred fortuitously on the winter solstice for those in the Northern Hemisphere and the beginning of summer in the global south.

The two planets were, in fact, more than 730 million kilometres (400 million miles) apart. But because of their alignment in relation to Earth, they appeared to be closer to each other than at any time in almost 400 years.

Optimal conjunction took place at 18:22 GMT.

Saturn and Jupiter set behind a church in New Jersey, US ahead of their conjunction that is being called The Christmas Star, in this December 18, 2020 photo [Gary Hershorn/Getty Images]

The best viewing conditions on Monday were in clear skies and close to the Equator, while people in Western Europe and along a vast swath of Africa had to train their sight to the southwest.

But hundreds of space fans also gathered in India’s Kolkata city to watch through a telescope at a technology museum in the city, or from surrounding rooftops and open areas.

And in Kuwait, astrophotographer travelled into the desert west of Kuwait City to capture the once-in-a-lifetime event.

Looking through a telescope or even a good pair of binoculars, the two gas giants were separated by no more than a fifth of the diameter of a full moon.

But with the naked eye, they would merge into a “highly luminous” double planet, said Florent Deleflie from the Paris Observatory.

“The Grand Conjunction refers to the period when two planets have relatively similar positions in relation to Earth,” said Deleflie.

“With a small instrument – even a small pair of binoculars – people can see Jupiter’s equatorial bands and its main satellites and Saturn’s rings.”

The last time Jupiter and Saturn nuzzled up this close was in 1623, but weather conditions in regions where the reunion could be seen blocked the view.

Visibility was apparently better the time before that during the Middle Ages, on March 4, 1226, to be precise.

Jupiter, which is the larger planet, takes 12 years to revolve around the sun, while Saturn takes 29 years.

Every 20 years or so, they appear to observers on Earth to come closer to each other.

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Creation by catastrophe – Skywatching – Castanet.net

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Collision of the Galaxies sounds like a good title for a spectacular disaster movie.

Actually, a lot of things in the universe depend on things smashing together, including galaxies. The object
Arp 299 is two galaxies in collision.

The two, designated NGC 3690 and IC 694, lying about 134 million light years away from us, have been in the process of collision for around 700 million years. The Hubble Space Telescope image can be found at https://en.wikipedia.org/wiki/Arp_299. The image is dotted with many bright, blue stars.

This is interesting because there are only two types of bright, blue star. One kind are young stars that will dim down a bit as they settle down.

The other kind are stars that collected an exceptionally large amount of hydrogen when they formed. These stars shine extremely brightly, run out of fuel soon, collapse and then explode. These explosions are called supernovae.

In either case, these blue stars cannot be very old. This relates to another interesting aspect of this pair of galaxies: the oddly large number of supernova explosions. What has produced these unusual circumstances?

If you look at a nearby spiral galaxy, such as our close neighbour, the Andromeda Galaxy, you will see the spiral arms glowing with little knots of pink, and sparkling with young stars.

If we could go a couple of million light years off into space, our galaxy, the Milky Way, would look much the same. The reason is that the spiral arms of galaxies are loaded with hydrogen gas, the primary ingredient for making stars.

If we look closer, we will see that these clouds are not uniform; some regions are much denser than others. On occasion, something triggers one of these denser regions to collapse, forming one or more stars.

These youngsters are hot and blue, and their high output of ultraviolet radiation makes the surrounding clouds glow pink. This pink, a characteristic of hydrogen, is known as hydrogen-alpha emission.

Therefore, when we look at a distant galaxy, those pink glows mean two things:

  • There is hydrogen to glow
  • Hot, blue stars to make it glow.

However, the jewel-box of bright, blue stars we see in the Arp 299 pair of galaxies is really unusual. Some major event caused massive collapses of hydrogen clouds, forming showers of new stars. We are pretty sure this outburst of star formation was caused by the two galaxies colliding.

Paradoxically, collisions between galaxies are not totally catastrophic; they trigger the formation of new stars and planets.

When we look at the computer simulations of collisions between galaxies (there are many on the web), they look pretty catastrophic. One can imagine stars and planets being annihilated on a huge scale.

The youtube on this link is a good example of what we believe a collision between two galaxies would look like. However, the situation is nothing like as bad as it looks.

The nearest star to us, after the Sun, lies about four light years away. This distance is fairly typical of the average distance between stars. So the chance of stars in two colliding galaxies passing close to one another is tiny. Even as fragments fly around and the galaxies combine, all the inhabitants of worlds in those galaxies will see is their equivalent of the Milky Way changing shape over millions of years.

However, for the gas clouds between the stars it’s a different matter. These will collide and collapse, forming lots of new stars.

We will get a chance to experience this first hand. The Milky Way and the Andromeda Galaxy are racing toward each other at 110 km/s, and will collide in about four billion years. There are computer simulations of this collision on the web.

  • The only easily visible planet is Mars, which can be found high in the southwest during the evening.
  • The Moon will reach First Quarter on the 20th.

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Oldest quasar and supermassive black hole discovered in the distant universe – CTV News

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The most distant quasar and the earliest known supermassive black hole have been discovered, shedding light on how massive galaxies formed in the early universe.

This discovery was revealed Tuesday at the 237th meeting of The American Astronomical Society, happening virtually due to the pandemic. The study has been accepted for publication in the Astrophysical Journal Letters.

A quasar, or quasi-stellar object, is the compact region at the center of a galaxy that throws off enormous energy. They emit so much energy that quasars appear like stars through a telescope. Astronomers believe that the supermassive black holes at the centers of galaxies actually power quasars, acting like an engine.

When gas falls into quasars at the centers of galaxies, they form disks of gas and dust that emit electromagnetic energy. This creates a brightness greater than entire galaxies.

Jets shoot out of the quasar, pulsing with X-rays, and they are some of the hottest things in the entire universe. The jets blow gas and dust, which are essential to form stars, out of the galaxy. When a quasar forms, it signals the end of a galaxy’s star-forming days.

This quasar is a thousand times more luminous than our Milky Way galaxy, and it’s powered by the earliest known supermassive black hole. The light from this quasar took more than 13 billion years to reach Earth, and astronomers were able to observe it as the quasar appeared just 670 million years after the Big Bang.

Its black hole engine weighs more than 1.6 billion times the mass of our sun, making it twice as massive as that of the previous record holder.

“This is the earliest evidence of how a supermassive black hole is affecting the galaxy around it,” said Feige Wang, lead study author and NASA Hubble fellow at the University of Arizona, in a statement. “From observations of less distant galaxies, we know that this has to happen, but we have never seen it happening so early in the Universe.”

The quasar has been dubbed J0313-1806 by the astronomers who discovered it.

“The most distant quasars are crucial for understanding how the earliest black holes formed and for understanding cosmic reionization — the last major phase transition of our Universe,” said Xiaohui Fan, study coauthor and regents professor of astronomy at the University of Arizona, in a statement.

To picture the brightness of this highly energetic object, imagine our sun — but 10 trillion times more luminous.

Astronomers were surprised to discover this quasar was fully formed in such a short time, astronomically speaking, after the Big Bang. The presence of the massive black hole that powers it at this early point in the universe’s timeline also challenges how astronomers understand black hole formation.

For example, how did this black hole have time to form?

“Black holes created by the very first massive stars could not have grown this large in only a few hundred million years,” Wang said.

Typically, such massive black holes form when giant stars explode and collapse, forming black holes that grow in size. They can also form when a dense cluster of stars collapses. Both of these take time.

“This tells you that no matter what you do, the seed of this black hole must have formed by a different mechanism,” Fan said. “In this case, it’s a mechanism that involves vast quantities of primordial, cold hydrogen gas directly collapsing into a seed black hole.”

The brightness of the quasar indicates that the black hole is gobbling up about 25 stars like our sun each year, which powers an outflow of gas moving at 20% the speed of light.

This loss of gas typically halts the birth of stars in a galaxy because that gas is a necessary ingredient in star formation.

“We think those supermassive black holes were the reason why many of the big galaxies stopped forming stars at some point,” Fan said.

Ultimately, the black hole will eventually run out of food, stunting its growth, Fan said.

Multiple telescopes were used in the discovery and astronomers are eager to observe it more in the future.

The galaxy that hosts the quasar is rapidly producing stars at a rate that is 200 times faster than the Milky Way.

“This would be a great target to investigate the formation of the earliest supermassive black holes,” Wang said. “We also hope to learn more about the effect of quasar outflows on their host galaxy — as well as to learn how the most massive galaxies formed in the early Universe.”

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Meet NASA Astronaut & Artemis Team Member Victor Glover [Video] – SciTechDaily

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Victor J. Glover, NASA astronaut candidate class of 2013. Credit: NASA

NASA astronaut Victor Glover is a member of the Artemis Team, a select group of astronauts charged with focusing on the development and training efforts for early Artemis missions.

Victor J. Glover, Jr. was selected as an astronaut in 2013 while serving as a Legislative Fellow in the United States Senate. He is currently serving as pilot and second-in-command on the Crew-1 SpaceX Crew Dragon, named Resilience, which launched November 15, 2020. It is the first post-certification mission of SpaceX’s Crew Dragon spacecraft – the second crewed flight for that vehicle – and a long duration mission aboard the International Space Station. He will also serve as Flight Engineer on the International Space Station for Expedition 64.

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The California native holds a Bachelor of Science in General Engineering, a Master of Science in Flight Test Engineering, a Master of Science in Systems Engineering and a Master of Military Operational Art and Science. Glover is a Naval Aviator and was a test pilot in the F/A‐18 Hornet, Super Hornet and EA‐18G Growler. He and his family have been stationed in many locations in the United States and Japan and he has deployed in combat and peacetime.

Through the Artemis program NASA and a coalition of international partners will return to the Moon to learn how to live on other worlds for the benefit of all. With Artemis missions NASA will send the first woman and the next man to the Moon in 2024 and about once per year thereafter.

Through the efforts of humans and robots, we will explore more of the Moon than ever before; to lead a journey of discovery that benefits our planet with life changing science, to use the Moon and its resources as a technology testbed to go even farther and to learn how to establish and sustain a human presence far beyond Earth.

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