Monthly Archives: February 2022

Astronomers have discovered the largest radio galaxy ever, stretching at least 16 million light-years through space, new research shows.

The galaxy named Alcyoneus after the son of Ouranos, the Greek primordial god of the sky was discovered about 3 billion light-years from Earth by a "stroke of luck," according to a statement from Leiden University in the Netherlands.

Radio galaxies house supermassive black holes at their cores. As matter falls into the black hole, it releases energy in the form of two radio jets from opposite sides from the galaxy's center, also known as an active galactic nucleus.

Related: Discovery of two new giant radio galaxies offers fresh insights into the universe

Using data from the Low-Frequency Array (LOFAR) network of radio telescopes located across Europe, researchers detected two massive plasma plumes emitted from a seemingly normal supermassive black hole at the center of the galaxy. Measuring at least 16 million light-years in length, these two jet streams stretch more than one hundred Milky Ways in diameter, representing the largest known structure of galactic origin, according to the statement.

The material blasted into space by these two jet streams includes the building blocks for new star formation. Traveling at almost the speed of light, this material heats up and dissolves into plasma, which glows in radio light that LOFAR is able to detect.

Astronomers using the radio telescopes were previously unable to detect Alcyoneus because the plumes are relatively faint. The researchers reprocessed existing images of the galaxy, revealing subtle, new patterns that alerted the team to the massive galactic structure.

While radio jets have been detected in many galaxies, including the Milky Way, the researchers are unsure how Alcyoneus grew to be so massive. At first, they thought it could be due to an usually large black hole, an exorbitant amount of stardust or incredibly powerful jet streams. However, these features appear relatively normal compared to other radio galaxies, according to the statement.

Alcyoneus may offer new clues about the structure of our universe, also known as the cosmic web, which is believed to connect all galaxies. This complex network is composed of filaments of clustered galaxies, separated by giant voids.

The intergalactic medium between galaxies may play a role in shaping the galaxy's massive plasma plumes. Therefore, the researchers plan to further investigate Alcyoneus' environment to see if anything in its surroundings can explain its unusual growth, according to the statement.

The findings have been accepted for publication in the journal Astronomy & Astrophysics.

Follow Samantha Mathewson @Sam_Ashley13. Follow us on Twitter @Spacedotcom and on Facebook.

See the article here:

Astronomers discover massive radio galaxy 100 times larger than the Milky Way - Space.com

The Milky Way galaxy feasted on more galaxies in its early days than astronomers thought.

The Gaia spacecraft uncovered the remains of an ancient cosmic collision in our Milky Way, revealing a previously unknown galaxy, now nicknamed "Pontus," absorbed by the Milky Way long before our galaxy looked the way it does now.

Pontus was a galaxy that strayed too close to the Milky Way and "fell in" to our galaxy's gravity about 8 billion to 10 billion years ago, the European Space Agency, which operates Gaia, said in a statement Thursday (Feb. 17).

Related: See a virtual Milky Way map from Europe's Gaia spacecraft

Events like this merger are important to learning about the Milky Way, ESA added, as it shows "the 'family tree' of smaller galaxies that has helped make the Milky Way what it is today."

Gaia launched into space nearly a decade ago, in 2013, on an ambitious mission to chart the sky in three dimensions more precisely than ever. Movements of stars and other objects nearby us will in turn reveal insights about the Milky Way's composition, formation and evolution, mission managers say on the Gaia website.

This latest work on galactic mergers arose from a study of the Milky Way's halo, which is a zone filled with globular clusters of older stars, stars that have low metallicity, and other interesting objects. "Foreign galaxies" in the halo may show up in this region in different ways, depending on the speed of the collision, ESA stated in the press release about the study.

"When a foreign galaxy falls into our own, great gravitational forces known as tidal forces pull it apart," ESA stated. "If this process goes slowly, the stars from the merging galaxy will form a vast stellar stream that can be easily distinguished in the halo. If the process goes quickly, the merging galaxy's stars will be more scattered throughout the halo and no clear signature will be visible."

Stars are not the only way by which we may detect a merging galaxy, however. If the intruder contains globular stars or small satellite galaxies, these may also show up in the halo. The new study focused on looking for this data.

Scientists named the incident after Greek mythology, which identifies Pontus as one of the first children of Gaia, the goddess of the Earth.

Besides finding the Pontus event, the team identified five other distinct merging groups (already known to science) and a possible sixth in the data. The already known five events are called Sagittarius, Cetus, Gaia-Sausage/Enceladus, LMS-1/Wukong, and Arjuna/Sequoia/Iitoi.

ESA noted that Pontus and most of these other events happened around the same time period, 8 billion to 10 billion years ago, but Sagittarius is more recent at 5 billion to 6 billion years ago. "As a result, the Milky Way has not yet been able to completely disrupt it," the agency added of the Sagittarius event.

A study based on the research was published Thursday (Feb. 17) in The Astrophysical Journal, led by Khyati Malhan, an astrophysicist at the Max Planck Institute for Astronomy in Heidelberg, Germany. The work was based upon an early release of Gaia's third large set of data, set to drop on June 13.

Follow Elizabeth Howell on Twitter@howellspace. Follow us on Twitter@Spacedotcomor Facebook.

Read this article:

Astronomers spot remains of long-lost galaxy eaten by the Milky Way - Space.com

Over the years, many have asked me to recommend books to help them in their study of the stars and constellations.

In this column, I'll provide reviews of three books that I consulted during my formative years in the hobby.

All three proved most valuable to me for my then-burgeoning interest in astronomy and I'm sure the same would hold true for most anyone who will take the time to use them today.

A Golden Guide from St. Martin's Press, 2001160 pages

This was my very first astronomy book, which I received at the age of 8, and is in my opinion still among the very best as an introduction to not only the stars and constellations, but astronomy as well. "Stars," first published in 1951, is one of a series of pocket Golden Guides on nature and physical science, which has been updated over the years, most recently in 2001.

The book was written by naturalist Herbert S. Zim (1909-1994) and astronomer Robert H. Baker (1883-1964). The latter was once head of the University of Illinois Department of Astronomy and was also the author of what is still considered a classic among college textbooks on astronomy ("Introduction to Astronomy," Van Nostrand publishers). Baker also authored two other excellent books, "When the Stars Come Out" and "Introducing the Constellations," both published by Viking Press.

Augmenting the text by Zim and Baker are 150 beautiful color paintings rendered by James Gordon Irving (1913-2012), whose paintings were exhibited at the American Museum of Natural History and the National Audubon Society in New York City.

This book was an immense help to me in identifying the brightest stars and constellations at a very young age. There are 23 maps that show constellations as lines connecting the principal naked-eye stars, traced within pictorial images of what each star pattern supposedly represented.

Additional charts and diagrams help, although the four seasonal star maps which are used to locate these stars are a bit confusing.

Nonetheless, the book contains a lot of valuable information and observing tips regarding the sun, moon, planets and stars, as well explanations for unusual atmospheric phenomena such as the sun's red color at sunrise and sunset, rainbows, lunar and solar haloes as well as the aurora borealis or northern lights.

If you're just starting out with astronomy as a hobby, this little handbook is perfect for anyone who wants to enjoy the wonders of the night sky. Written in easy-to-read language, it is ideal for use at home, as well as to take along on a vacation or a camping trip.

Houghton Mifflin Company, Boston, 2008160 pages

As I noted for the Golden Guide's "Stars," there were pictorial images of the person, creature or object that a constellation represented. But 70 years ago, Hans Augusto Rey (1898-1977) devised a different methodology of identifying the constellations using his own stick-figure star patterns and introducing them in "The Stars: A New Way to See Them," a guidebook published in 1952 and revised several times ever since. Indeed, this book has been extremely popular, going through a number of printings and selling hundreds of thousands of copies. Many people swear by Rey's patterns, claiming they are easier to learn and see in the sky.

I first came across a copy of Rey's book when I was 10 years old and was immediately intrigued by a number of his clever creations, such as the Gemini twins holding hands (most often used in advertising the book).

There are, however, many legends and mythological stories that date back thousands of years explaining the creation of the constellations. But for his book, Rey for the most part has ignored these ancient legends and performed radical surgery on virtually all of the constellations, seemingly to conform solely to his ideas as to what a particular star picture should look like.

It makes one wonder who had the more fertile imagination: those cultures who actually invented the constellations all those many centuries ago, or Rey himself?

Some examples:

For Ursa Major, Rey made the end of the Big Dipper's handle long regarded in mythology as the tail of the Great Bear into its nose!

In the case of Cetus, the whale, he turned that mammal's tail into its face, even though the star Deneb Kaitos is located there; Arabic for the southern tail of Cetus.

Hercules has always been considered a kneeling giant with its brightest star, Rasalgethimarking "the head of the kneeler." But Rey turns Hercules into a man wielding a club with Rasalgethi marking his left foot.

As for Virgo, her brightest star, Spica, is supposed to mark a spike of wheat held in her hand. But according to Rey, Spica is the Virgin's "brightest jewel," positioned he writes, "on an unusual spot" (her derrire).

And then in those cases where some constellations came reasonably close to depicting what they represented, Rey could not leave well enough alone. In some cases, like with Pegasus, the flying horse and Taurus, the bull, his stick-figure renditions were decidedly forced and not really all that obvious, looking more like abstract art something resembling sketches by Pablo Picasso.

Despite these drawbacks, I still very much like "The Stars: A New Way to See Them" as an easy-to-comprehend work that, among other things, explains to the novice how not mistake a planet for a star and cites the reasons for planetary movements. The speed of light and light-years are explained on a totally non-technical level, and overall, this book does an admirable job in explaining some of the complicated concepts about the night sky and what it contains.

And I would even regard Rey's abstract patterns as a challenge to those who wish to hone their star-finding skills.

Harper and Row, New York, 1970334 pages

From time to time, I have mentioned Henry M. Neely (1877-1963) who, after a distinguished career in radio, took up astronomy relatively late in life. He was a longtime lecturer at New York's Hayden Planetarium and became one of the nation's leading popularizers of astronomy. Sadly, he died before I had a chance to hear any of his lectures, but Neely wanted everyone to share in the beauty and splendor of the heavens. His 1946 book "A Primer for Star-Gazers" was last updated in 1970 and remains a powerful yet simple tool in the study of the stars and constellations.

Unfortunately, revised distances for many stellar and deep-sky objects dating back to the book's first edition were never updated. Thus, on page 195, the Andromeda galaxy is listed as being 750,000 light-years away, whereas current figures are more than three times as great. But the author's aim in this book is to help you find the stars, not to fill you with facts and figures. Neely visualized his reader as wanting simply to recognize the principal stars and constellations without making a real study of astronomy.

"A Primer" follows this philosophy from cover to cover. It contains 96 sky maps all drawn by Neely, with all navigational stars indicated as such, and with a unique calendar that tells which maps to use for prominent objects. This book proves itself to be an elaborate yet easy-to-use star finder. Follow the instructions in Chapter 5 ("How to Use This Book"), then go outside, select the proper map for the evening, rotate the book as directed, look at the page, then at the sky, and there should be the desired constellation. Phonetic spellings of star and constellation names are given next to the regular spellings. The Big and Little Dippers and Cassiopeia's "W" are chosen as the first groups to recognize, for later use in locating others. The book provides excellent descriptions of how to find each constellation and notable objects within it.

Neely had a predilection for turning some classical star patterns into geometric shapes. Thus, we are introduced to "The Kite in Auriga," "The Long Wedge of Gemini," "The Great Virgo Triangle," and depicting Hercules as yet another kite ... but also with a tail.

He may well have been the very first to turn Sagittarius from an archer into a teapot (Chapter XXIV) and on page 187, he incorporated the stars of Cygnus, Lyra and Aquila into a baseball game in the sky. Deneb was home plate; Epsilon Cygni, first base; Eta, second base; Delta, third base; and Sadr, the pitcher's mound. Left fielder Vega and center fielder Albireo are running to catch a fly ball in left-center field, while Altair, the right fielder, watches. Such imaginative variants of constellations are quite effective in teaching the sky, especially to youngsters.

The only negative for this book that I would register is in Chapter 16, where Neely turns the constellations of Andromeda, Perseus, Aries and Triangulum into his own creation: The Yacht.

I must tell you that in all my years of skywatching, I have never been able to visualize it, even though Neely claims that, "... it does not require nearly as great a stretch of the imagination as many of the traditional figures allegedly seen by ancient stargazers."

With all due respect to Neely, I disagree!

Like some of Rey's creations, The Yacht is a highly abstract star pattern. Good luck with it!

Overall, however, this fine book should make the task of a beginner to locate all the stars and constellations noted in this text quite easy and, as Henry Neely himself would like it to be, most enjoyable.

Joe Rao serves as an instructor and guest lecturer at New York'sHayden Planetarium. He writes about astronomy forNatural History magazine, theFarmers' Almanacand other publications. Follow uson Twitter@Spacedotcomand onFacebook.

Link:

Book reviews for three guides to the stars and constellations - Space.com

University of Arizona astronomy students are tracking the object projected to crash into the Moon later this spring.

UA planetary sciences professor Vishnu Reddy says his students met the challenge of confirming the object is a spent booster stage of a Chinese rocket launched in 2014.

We observed it with a telescope on campus and were able to compare similar boosters left in Earth orbit by other missions," explained Reddy. "We compared one from Space X and one from the Chinese mission and it turns out we got a pretty good match.

Scientists predict the rocket stage will impact the far side of the Moon in early March.

It wont be visible from Earth, but Reddy says astronomers are aiming to get photographs of the eventual crash site from the Lunar Reconnaissance Orbiter already circling the Moon.

Follow this link:

University of Arizona astronomy researchers track space junk to the Moon - AZPM - Arizona Public Media

View larger. | Location of asteroid 1999 VF22 on the night of February 21, 2022, just hours before its closest approach. Facing north with a 12 or larger diameter telescope. Illustration by Eddie Irizarry/ Stellarium.

A cruise-ship-sized space rock called 1999 VF22 will safely pass Earth on February 22, 2022. Itll be this particular space rocks closest approach in more than 100 years. Closest approach will be at 2:54 a.m. EST (07:54 UTC) on February 22. The asteroid will pass us at a distance of 3.3 million miles (5.4 million km) or almost 14 times the Earth-moon distance. Despite this safe expanse, it will still be close enough for astronomers to study the asteroid using radar. The Virtual Telescope will also air its flyby live. And you can use a (large) backyard telescope to watch it slide past.

Asteroid 1999 VF22 will come slightly closer in 128 years, when it returns on February 23, 2150.

This isnt a newly discovered asteroid. The Catalina Sky Survey in Arizona discovered it way back on November 10, 1999. The date of discovery is how asteroid 455176 got its designation of 1999 VF22.

The 2022 lunar calendars are still available. Order yours before theyre gone!

Asteroid 1999 VF22 is traveling at 56,158 miles per hour (25.1 km/s) relative to Earth. Even though it will pass at a safe distance, its still classified as a Potentially Hazardous Asteroid due to its predicted close passes by Earth.

From February 19 to 24, astronomers will point the 230-foot (70-meter) DSS-14 Goldstone Radar Antenna in California at the space rock.They plan to study this asteroid, which appears to completeone revolutionevery four hours.

What do we already know? We know that asteroid 1999 VF22 has an average size of 1,017 feet (310 meters) in diameter. Previous radar studies from the Arecibo Observatory revealed it to be a rounded space rock.

And we know that 1999 VF22 orbits the sun every 1 1/2 years. So it sometimes passes close not only to Earth, but also to Mars, Venus and Mercury.

You can see the asteroid yourself with a 12-inch or larger diameter telescope. No telescope? No problem. You can also watch it live from the Virtual Telescope starting at 00:00 UTC on February22.

Bottom line: Asteroid 1999 VF22 will swing past Earth at a safe distance on February 22, 2022. You can watch the event live via Virtual Telescope.

Eddie Irizarry of the Sociedad de Astronoma del Caribe (Astronomical Society of the Caribbean) has been a NASA Solar System Ambassador since 2004. He loves public outreach and has published multiple astronomy articles for EarthSky, as well as for newspapers in Puerto Rico. He has also offered dozens of conferences related to asteroids and comets at the Arecibo Observatory. Asteroid 33012EddieIrizarry, a 7.8 km space rock, has been named in his honor.

The rest is here:

Watch live as an asteroid safely passes Earth on February 22 - EarthSky

February 16, 2022 marked the 66th death anniversary of Indian astrophysicist Meghnad Saha, who is widely renowned for his 'Saha ionisation equation', mainly used to describe physical and chemical conditions in stars. It is also thanks to Saha's work astronomers can accurately relate the spectral classes of stars to their actual temperatures.

The late astrophysicist's research work on the thermal ionisation of elements led him to come up with what is now known as the Saha equation. As per the equation, it is the basic tool for interpreting the spectra of stars in astrophysics. Through the study of the ranges of various stars, one can find their temperature and, using Saha's equation, determine the ionisation state of the various elements making up the star. His work was also soon extended by Edward Arthur Milne and Ralph H. Fowler, as per Wikipedia.

Meghnad Saha also was the one who invented an instrument to measure the pressure and weight of solar rays and assisted in building numerous scientific institutions, such as the Institute of Nuclear Physics in Calcutta and the Physics Department in Allahabad University. The late astrophysicist founded the journal Science and Culture and was also the editor until he passed away.

Furthermore, Saha was also the leading spirit in organising several scientific societies, such as the Indian Institute of Science (1935), the Indian Physical Society (1934), National Academy of Science (1930). The visionary Indian was also the Director at the Indian Association for the Cultivation of Science between 19531956. Founded in 1943, the Saha Institute of Nuclear Physics in Kolkata is named after him as well.

Born on October 6, 1893, in Shaoratoli, a small village near Dhaka, in the former Bengal Presidency of British India (now Bangladesh), Meghnad Saha struggled to rise in life and was forced to leave Dhaka Collegiate School due to his participation in the Swadeshi movement.

Saha died on February 16, 1956, at the age of 62, due to a cardiac arrest in New Delhi while he was on his way to the office of the Planning Commission in Rashtrapati Bhavan. He reportedly collapsed a few yards away from there and passed away on the way to the hospital at 10:15 a.m. (IST).

Furthermore, reports also revealed that he had been suffering from hypertension for ten months before his death. His remains were cremated at the Keoratola crematorium in Kolkata the following day.

Also Read: Drones Made By IIT-Delhi-Incubated Startup Lit Up Sky At Beating Retreat Ceremony

More here:

Meghnad Saha: Indian Astrophysicist Who Revolutionised Astronomy With His Saha Ionisation Equation - The Logical Indian