galaxies Archives

September 14, 2020September 14, 2020 by Brian Koberlein

Small Amounts of Dark Matter are Creating Much Stronger Gravitational Distortions than Anyone Expected to See

A mosaic of telescopic images showing the galaxies of the Virgo Supercluster. It's part of the cosmic web in which a galaxy can exist during part of its evolution. Credit: NASA/Rogelio Bernal Andreo

Dark matter is difficult for astronomers to study, but that doesn’t keep them from trying. And with skill and determination, they continue to find exciting things about the invisible stuff.

July 7, 2020July 7, 2020 by Nancy Atkinson

NGC 2275: An Absolute Unit of Galactic Flocculence

The spiral pattern shown by the galaxy NGC 2275 in this image from the NASA/ESA Hubble Space Telescope is striking because of its delicate, feathery nature. Credit: ESA/Hubble & NASA, J. Lee and the PHANGS-HST Team; Acknowledgment: Judy Schmidt (Geckzilla)

The Hubble Space Telescope has the knack for finding every size and shape of galaxy imaginable – from small, medium to large, all the way up to that funky size of absolute units.

June 16, 2020June 16, 2020 by Evan Gough

Barred Spiral Galaxy NGC 2608, Surrounded by Many Many Other Galaxies

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.

Meet NGC 2608, a barred spiral galaxy about 93 million light years away, in the constellation Cancer. Also called Arp 12, it’s about 62,000 light years across, smaller than the Milky Way by a fair margin. The Hubble Space Telescope captured this image with its Wide-Field Camera 3 (WFC3).

June 9, 2020June 9, 2020 by Evan Gough

Hubble Photo of Globular Cluster NGC 6441, One of the Most Massive in the Milky Way

NGC 6441 is one of the most luminous and massive globular clusters in the Milky Way. It also hosts fours pulsars. Image Credit: ESA/Hubble & NASA, G. Piotto

The Hubble Space Telescope has delivered another outstanding image. This one is of NGC 6441, a massive globular cluster in the constellation Scorpius. It’s one of the most massive ones in the Milky Way, and the stars in it have a combined mass of 1.6 million solar masses.

June 5, 2020June 5, 2020 by Nancy Atkinson

Hubble Looked as Far Back in Time as it Could, and Still Couldn’t See the First Generation of Stars in the Universe

New results from the NASA/ESA Hubble Space Telescope suggest the formation of the first stars and galaxies in the early Universe took place sooner than previously thought. A European team of astronomers have found no evidence of the first generation of stars, known as Population III stars, when the Universe was less than one billion years old. This artist’s impression presents the early Universe. Image Credit: ESA/Hubble, M. Kornmesser.

Astronomers don’t know exactly when the first stars formed in the Universe because they haven’t been observed yet. And now, new observations from the Hubble Space Telescope suggest the first stars and galaxies may have formed even earlier than previously estimated.

Why? We *still* haven’t seen them, even with the best telescope we’ve got, pushed to its limits.

June 3, 2020June 3, 2020 by Brian Koberlein

Study of 200,000 Galaxies Reveals the Entire Universe Might Have Been Spinning in One Direction Early On

Some of the most dramatic events in the Universe occur when certain stars die — and explode catastrophically in the process. Such explosions, known as supernovae, mainly occur in a couple of ways: either a massive star depletes its fuel at the end of its life, become dynamically unstable and unable to support its bulk, collapses inwards, and then violently explodes; or a white dwarf in an orbiting stellar couple syphons more mass off its companion than it is able to support, igniting runaway nuclear fusion in its core and beginning the supernova process. Both types result in an intensely bright object in the sky that can rival the light of a whole galaxy. In the last 20 years the galaxy NGC 5468, visible in this image, has hosted a number of observed supernovae of both the aforementioned types: SN 1999cp, SN 2002cr, SN2002ed, SN2005P, and SN2018dfg. Despite being just over 130 million light-years away, the orientation of the galaxy with respect to us makes it easier to spot these new ‘stars’ as they appear; we see NGC 5468 face on, meaning we can see the galaxy’s loose, open spiral pattern in beautiful detail in images such as this one from the NASA/ESA Hubble Space Telescope.

Almost everything in the universe spins. Planets rotate on their axis, stars spin around black holes, and galaxies spin in great spiral structures. But what about the universe as a whole?

June 3, 2020June 3, 2020 by Evan Gough

Barred Spiral NGC 3895 Captured by Hubble

Far away in the Ursa Major constellation is a swirling galaxy that would not look out of place on a coffee made by a starry-eyed barista. NGC 3895 is a barred spiral galaxy that was first spotted by William Herschel in 1790 and was later observed by the NASA/ESA Hubble Space Telescope. Hubble's orbit high above the Earth's distorting atmosphere allows astronomers to make the very high resolution observations that are essential to opening new windows on planets, stars and galaxies — such as this beautiful view of NGC 3895. The telescope is positioned approximately 570 km above the ground, where it whirls around Earth at 28 000 kilometres per hour and takes 96 minutes to complete one orbit.

NGC 3895 is a barred spiral galaxy in the Ursa Major constellation. It’s about 145 million light years away from our home, the Milky Way, and its diameter is about 45,000 light years. William Herschel discovered it way back in 1790.

Now the Hubble Space Telescope has given us another gorgeous image of it. Thanks Hubble!

May 27, 2020May 27, 2020 by Evan Gough

A Massive Rotating Disc Discovered in the Early Universe

Artist impression of the Wolfe Disk, a massive rotating disk galaxy in the early, dusty universe. Credit: NRAO/AUI/NSF, S. Dagnello

If we want to understand how the Universe evolves, we have to understand how its large structures form and evolve. That’s why astronomers study galaxy formation. Galaxies are enormous structures of stars, planets, gas, dust, and dark matter, and understanding how they form is critical to understanding the Universe itself.

In 2017, astronomers working with ALMA (Atacama Large Millimeter/sub-millimeter Array) discovered an ancient galaxy. This massive rotating disk galaxy was born when the Universe was only about 1.5 billion years old. According to the most accepted understanding of how galaxies form and evolve, it shouldn’t exist.

But there it is.

May 27, 2020May 27, 2020 by Nancy Atkinson

This Dwarf Galaxy is all by Itself

Unlike a spiral or elliptical galaxy, the galaxy KK 246 looks like glitter spilled across a black velvet sheet. KK 246, also known as ESO 461-036, is a dwarf irregular galaxy residing within the Local Void. This image is made up of observations from Hubble’s Wide Field Camera 3 (WFC3) and Advanced Camera for Surveys (ACS) in the infrared and optical parts of the spectrum. Four filters were used to sample various wavelengths. The color results from assigning different hues to each monochromatic image associated with an individual filter. Image credit: NASA/ESA/Hubble/E. Shaya et al.

In these days of social distancing, it appears this beautiful little galaxy is leading by example, sitting all by itself in the middle of a cosmic void.

KK 246, also known as ESO 461-036, is a dwarf irregular galaxy, and ESA aptly described this picture as looking like “glitter spilled across a black velvet sheet.”

But the serene view can be deceiving.

April 1, 2020April 1, 2020 by Evan Gough

This Galaxy Has Only One Spiral Arm

NGC 4618, the one-armed galaxy. Image Credit: ESA/Hubble & NASA, I. Karachentsev; CC BY 4.0

There are all kinds of odd things in the sky. Things that defy our naming conventions, and our attempts to understand them. For instance, NGC 4618, the one-armed galaxy.