milky way galaxy Archives

October 25, 2022October 25, 2022 by Evan Gough

Maybe We Don’t See Aliens Because Nobody Wants to Come Here

Artist impression of an alien civilization. Image credit: CfA

The Fermi Paradox won’t go away. It’s one of our most compelling thought experiments, and generations of scientists keep wrestling with it. The paradox pits high estimates for the number of civilizations in the galaxy against the fact that we don’t see any of those civs. It says that if rapidly expanding civilizations exist in the Milky Way, one should have arrived here in our Solar System. The fact that none have implies that none exist.

Many thinkers and scientists have addressed the Fermi Paradox and tried to come up with a reason why we don’t see any evidence of an expanding technological civilization. Life may be extraordinarily rare, and the obstacles to interstellar travel may be too challenging. It could be that simple.

But a new paper has a new answer: maybe our Solar System doesn’t offer what long-lived, rapidly expanding civilizations desire: the correct type of star.

August 18, 2022August 18, 2022 by Matt Williams

A New Image From Webb Shows Galaxy NGC 1365, Known to Have an Actively Feeding Supermassive Black Hole

The barred spiral galaxy NGC 1365. Credit: NASA/JPL-Caltech/Judy Schmidt

The James Webb Space Telescope continues to deliver stunning images of the Universe, demonstrating that the years of development and delays were well worth the wait! The latest comes from Judy Schmidt (aka. Geckzilla, SpaceGeck), an astrophotographer who processed an image taken by Webb of the barred spiral galaxy NGC 1365. Also known as the Great Barred Spiral Galaxy, NGC 1365 is a double-barred spiral galaxy consisting of a long bar and a smaller barred structure located about 56 million light-years away in the southern constellation Fornax.

March 29, 2022March 29, 2022 by Evan Gough

Part of the Milky Way Is Much Older Than Previously Believed

Basic structure of our home galaxy, edge-on view. The new results from ESA's Gaia mission provide for a reconstruction of the history of the Milky Way, in particular of the evolution of the so-called thick disc. Image Credit: Stefan Payne-Wardenaar / MPIA

The Milky Way is older than astronomers thought, or part of it is. A newly-published study shows that part of the disk is two billion years older than we thought. The region, called the thick disk, started forming only 0.8 billion years after the Big Bang.

January 1, 2022January 1, 2022 by Matt Williams

A Detailed Scan of the Milky Way Finds Possible “Fossil” Spiral Arms

Looking deep into the Universe, the NASA/ESA Hubble Space Telescope catches a passing glimpse of the numerous arm-like structures that sweep around this barred spiral galaxy, known as NGC 2608. Appearing as a slightly stretched, smaller version of our Milky Way, the peppered blue and red spiral arms are anchored together by the prominent horizontal central bar of the galaxy. In Hubble photos, bright Milky Way stars will sometimes appear as pinpoints of light with prominent lens flares. A star with these features is seen in the lower right corner of the image, and another can be spotted just above the pale centre of the galaxy. The majority of the fainter points around NGC 2608, however, lack these features, and upon closer inspection they are revealed to be thousands of distant galaxies. NGC 2608 is just one among an uncountable number of kindred structures. Similar expanses of galaxies can be observed in other Hubble images such as the Hubble Deep Field which recorded over 3000 galaxies in one field of view.

As we learn more about the cosmos, it’s interesting how some of the greatest discoveries continue to happen close to home. This is expected to continue well into the future, where observations of Cosmic Dawn and distant galaxies will take place alongside surveys of the outer Solar System and our galaxy. In this latter respect, the ESA’s Gaia observatory will continue to play a vital role. As an astrometry mission, Gaia has been to determine the proper position and radial velocity of over a billion stars to create a three-dimensional map of the Milky Way.

Using data from Gaia’s third early Data Release (eDR3) and Legacy Survey data – from the Sloan Digital Sky Survey (SDSS) – an international team of astronomers created a new map of the Milky Way’s outer disk. In the process, they discovered evidence of structures in this region that include the remnants of fossil spiral arms. This discovery will shed new light on the formation and history of the Milky Way and may lead to a breakthrough in our understanding of galactic evolution.

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.

August 21, 2021August 21, 2021 by Brian Koberlein

The Milky Way Broke one of its Arms

A contingent of stars and star-forming clouds was found jutting out from the Milky Way's Sagittarius Arm. Credit: NASA/JPL-Caltech

The Milky Way galaxy is our home, and yet in some ways, it is the least understood galaxy. One of the biggest challenges astronomers have is in understanding its large-scale structure. Because we’re in the midst of it all, mapping our galaxy is a bit like trying to map the size and shape of a wooded park while standing in the middle of it.

January 6, 2021January 5, 2021 by Paul M. Sutter

There Should be a few Supernovae in the Milky Way Every Century, but we’ve Only Seen 5 in the Last 1000 Years. Why?

This image of the supernova remnant SN 1987A was taken by the NASA/ESA Hubble Space Telescope in January 2017 using its Wide Field Camera 3 (WFC3). Since its launch in 1990 Hubble has observed the expanding dust cloud of SN 1987A several times has helped astronomers get a better understanding of these cosmic explosions. Supernova 1987A is located in the centre of the image amidst a backdrop of stars. The bright ring around the central region of the exploded star is material ejected by the star about 20 000 years before the actual explosion took place. The supernova is surrounded by gaseous clouds. The clouds’ red colour represents the glow of hydrogen gas. Image Credit: NASA, ESA, and R. Kirshner (Harvard-Smithsonian Center for Astrophysics and Gordon and Betty Moore Foundation) and P. Challis (Harvard-Smithsonian Center for Astrophysics)

Our galaxy hosts supernovae explosions a few times every century, and yet it’s been hundreds of years since the last observable one. New research explains why: it’s a combination of dust, distance, and dumb luck.

January 4, 2021January 4, 2021 by Matt Williams

Astronomers Discover Hundreds of High-Velocity Stars, Many on Their Way Out of the Milky Way

Since discovering the first one in 2005, astronomers have found hundreds of stars that travel fast enough that they could escape the Milky Way as HVSs. Image Credit: NAOC/Kong Xiao

Within our galaxy, there are thousands of stars that orbit the center of the Milky Way at high velocities. On occasion, some of them pick up so much speed that they break free of our galaxy and become intergalactic objects. Because of the extreme dynamical and astrophysical processes involved, astronomers are most interested in studying these stars – especially those that are able to achieve escape velocity and leave our galaxy.

However, an international team of astronomers led from the National Astronomical Observatories of China (NAOC) recently announced the discovery of 591 high-velocity stars. Based on data provided by the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) and the ESA’s Gaia Observatory, they indicated that 43 of these stars are fast enough to escape the Milky Way someday.

November 17, 2020November 19, 2020 by Paul M. Sutter

The family tree of the Milky Way. The mergers that gave us the galaxy we see today

An edge-on view of a spiral galaxy. Credit: ESO

Galaxies build themselves up slowly over time by cannibalizing their neighbors. Using an advanced suite of computer simulations, researchers have now traced back the evolutionary history of our own Milky Way.

November 3, 2020November 3, 2020 by Evan Gough

The Spherical Structure at the Core of the Milky Way Formed in a Single Burst of Star Formation

This artist’s impression shows how the Milky Way galaxy would look seen from almost edge on and from a very different perspective than we get from the Earth. The central bulge shows up as a peanut shaped glowing ball of stars and the spiral arms and their associated dust clouds form a narrow band. Image Credit: By ESO/NASA/JPL-Caltech/M. Kornmesser/R. Hurt - http://www.eso.org/public/images/eso1339a/, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=28256788

Like other spiral galaxies, the Milky Way has a bulging sphere of stars in its center. It’s called “The Bulge,” and it’s roughly 10,000 light-years in radius. Astronomers have debated the bulge’s origins, with some research showing that multiple episodes of star formation created it.

But a new survey with the NOIRLab’s Dark Energy Camera suggests that one single epic burst of star formation created the bulge over 10 billion years ago.