milky way Archives

February 14, 2022February 14, 2022 by Evan Gough

Astronomers Scan the Center of the Milky Way for Any Sign of Intelligent Civilizations. Nothing but Silence.

This is an image of the center of the Milky Way. The bright white area right of center is home of the supermassive black hole Sagittarius A star. Image Credit: By NASA/JPL-Caltech/ESA/CXC/STScI - http://photojournal.jpl.nasa.gov/catalog/PIA12348See also http://www.spacetelescope.org/images/opo0928a/ and http://hubblesite.org/newscenter/archive/releases/2009/28/image/a/, Public Domain, https://commons.wikimedia.org/w/index.php?curid=24958921

Are there civilizations somewhere else in the Universe? Somewhere else in the Milky Way? That’s one of our overarching questions, and an answer in the affirmative would be profound.

Humanity’s pursued the Search for Extraterrestrial Intelligence (SETI) in one form or another since shortly after the advent of radio waves in the early 20th century. Efforts have waxed and waned over the decades, but the search has never been completely abandoned.

The search detected transient hints in the form of unexplained radio waves in the past, but nothing that comprises reliable evidence. Now a new search for technosignatures in the Milky Way’s center has turned up nothing.

January 14, 2022January 14, 2022 by Evan Gough

Nearby Supernovae Exploded Just a few Million Years Ago, Leading to a Wave of Star Formation Around the Sun

Artist's illustration of the Local Bubble with star formation occurring on the bubble's surface. Scientists have now shown how a chain of events beginning 14 million years ago with a set of powerful supernovae led to the creation of the vast bubble, responsible for the formation of all young stars within 500 light years of the Sun and Earth. Credit: Leah Hustak (STScI)

The Sun isn’t the only star in this galactic neighbourhood. Other stars also call this neighbourhood home. But what’s the neighbourhood’s history? What triggered the birth of all those stars?

A team of astronomers say they’ve pieced the history together and identified the trigger: a series of supernovae explosions that began about 14 million years ago.

January 6, 2022January 6, 2022 by Evan Gough

An Incredible View Into the Heart of the Small Magellanic Cloud

A radio-telescope image of the Small Magellanic Cloud reveals more detail than ever seen before. Image Credit: N. Pingel et al.

The Small Magellanic Cloud (SMC) is over 200,000 light-years away, yet it’s still one of our galaxy’s closest neighbours in space. Ancient astronomers knew of it, and modern astronomers have studied it intensely. But the SMC still holds secrets.

By studying it and revealing its structure in more detail, astronomers at The Australian National University hope to grow our understanding of the SMC and galaxies in general.

December 23, 2021December 23, 2021 by Matt Williams

Best Image Ever Taken of Stars Buzzing Around the Milky Way’s Supermassive Black Hole

This visible light wide-field view shows the rich star clouds in the constellation of Sagittarius (the Archer) in the direction of the centre of our Milky Way galaxy. The entire image is filled with vast numbers of stars — but far more remain hidden behind clouds of dust and are only revealed in infrared images. This view was created from photographs in red and blue light and forming part of the Digitized Sky Survey 2. The field of view is approximately 3.5 degrees x 3.6 degrees.

It all began with the discovery of Sagittarius A*, a persistent radio source located at the Galactic Center of the Milky Way that turned out to be a supermassive black hole (SMBH). This discovery was accompanied by the realization that SMBHs exist at the heart of most galaxies, which account for their energetic nature and the hypervelocity jets extending from their center. Since then, scientists have been trying to get a better look at Sag A* and its surroundings to learn more about the role SMBHs play in the formation and evolution of our galaxy.

This has been the goal of the GRAVITY collaboration, an international team of astronomers and astrophysicists that have been studying the core of the Milky Way for the past thirty years. Using the ESO’s Very Large Telescope Interferometer (VLTI), this team obtained the deepest and sharpest images to date of the region around Sag A*. These observations led to the most precise measurement yet of the black hole’s mass and revealed a never-before-seen star that orbits close to it.

November 23, 2021 by Nancy Atkinson

Once New Horizons was out Beyond Pluto, it Could Finally Measure the Brightness of the Milky Way

This false-color map shows several scans of the Lyman-alpha background over the sky, obtained by the Alice ultraviolet spectrograph on the New Horizons spacecraft when it was 45 AU from the Sun. The data agrees well with an underlying model of the solar component of the Lyman-alpha background to which a constant brightness from the Milky Way has been added. The background is brighter at both directions near our Sun, which is marked here by an orange dot. Credit: SwRI

The New Horizons spacecraft has been speeding away from Earth since it launched in 2006. Scientists using the Alice UV imaging spectrograph on board New Horizons, have been patiently but sporadically gathering data during those 15 years, but also waiting to get far enough away from the Sun to make a specific measurement: the brightness of the Lyman-alpha background of the Milky Way. Until now, this had never been measured accurately.

November 15, 2021November 15, 2021 by Nancy Atkinson

A Black Hole has been Found Lurking Just Outside the Milky Way

This artist’s impression shows a compact black hole 11 times as massive as the Sun and the five-solar-mass star orbiting it. The two objects are located in NGC 1850, a cluster of thousands of stars roughly 160 000 light-years away in the Large Magellanic Cloud, a Milky Way neighbour. The distortion of the star’s shape is due to the strong gravitational force exerted by the black hole. Not only does the black hole’s gravitational force distort the shape of the star, but it also influences its orbit. By looking at these subtle orbital effects, a team of astronomers were able to infer the presence of the black hole, making it the first small black hole outside of our galaxy to be found this way. For this discovery, the team used the Multi Unit Spectroscopic Explorer (MUSE) instrument at ESO’s Very Large Telescope in Chile. Credit: ESO/M. Kornmesser

Astronomers have found a smaller, stellar-mass black hole lurking in a nearby satellite galaxy of our own Milky Way. The black hole has been hiding in a star cluster named NGC 1850, which is one of the brightest star clusters in the Large Magellanic Cloud. The black hole is 160,000 light-years away from Earth, and is estimated to be about 11 times the mass of our Sun.

October 20, 2021October 20, 2021 by Evan Gough

The Large Magellanic Cloud Stole one of its Globular Clusters

The Milky Way with the Small and Large Magellanic Clouds on the left. Image Credit: ESO/Y. Beletsky. CC 4.0

Astronomers have known for years that galaxies are cannibalistic. Massive galaxies like our own Milky Way have gained mass by absorbing smaller neighbours.

Now it looks like smaller galaxies like the Large Magellanic Cloud have also feasted on smaller neighbours.

October 18, 2021October 18, 2021 by Evan Gough

What’s Causing the Mysterious Radio Waves Coming From the Center of the Milky Way?

An artist's impression of ASKAP J173608.2-321635, the mysterious radio source at the center of the Milky Way. Image Credit: Sebastian Zentilomo.

The center of the Milky Way is a mysterious place. Astronomers think there’s a supermassive black hole there, though it could be dark matter instead. The region is densely packed with stars, dominated by red giants. And because of all the dust between Earth and the galactic center, we can’t see anything with visible light, ultraviolet light, or low-energy x-rays.

But we can detect radio waves, and there are some unexplained ones coming from the center of the galaxy, and adding to the mystery.

October 18, 2021October 18, 2021 by Evan Gough

A Magnetic Tunnel Surrounds the Earth

The sky as it would appear in radio polarized waves. The Van-Gogh-like lines show magnetic field orientation. Image Credit: Pixabay/wal_172619, with edits by J. West.

What if our eyes could see radio waves?

If we could, we might be able to look up into the sky and see a tunnel of rope-like filaments made of radio waves. The structure would be about 1,000 light-years long and would be about 350 light-years away.

This tunnel explains two of the brightest radio features in the sky.

September 13, 2021September 10, 2021 by Paul M. Sutter

The Milky Way Hasn’t Been Evenly Mixed

Artist impression: Clouds and streams of cosmic pristine gas (magenta) accrete onto the Milky Way, but this gas does not efficiently mix in the Galactic disk, as highlighted for the Solar neighborhood (zoom-in). © Dr Mark A. Garlick

Gas from the intergalactic medium constantly rains down on galaxies, fueling continued star formation. New research has shown that this gas is not evenly mixed, and stars are not equal across the galaxy. This result means that solar systems are not the same within the Milky Way.