Tag: Hubble Space Telescope

Hubble data shows expansion of supernova remnant

9:57 am

Cygnus loop filament

Astronomers have created a four-second long movie using Hubble images collected over twenty years that shows the expansion of one filament in the Cygnus Loop supernova remnant, the explosion of which is thought to have occurred 20,000 years ago.

The picture above is one frame of that movie. The filament is estimated to be two light years in length.

By analyzing the shock’s location, astronomers found that the shock hasn’t slowed down at all in the last 20 years, and is speeding into interstellar space at over half a million miles per hour – fast enough to travel from Earth to the Moon in less than half an hour. While this seems incredibly fast, it’s actually on the slow end for the speed of a supernova shock wave.

Two versions of the movie are at the link, with the longer providing excellent context.

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Two galaxies merging

11:32 am

Merging galaxies
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Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken by the Hubble Space Telescope as part of a survey project to photograph the entire Arp catalog of 338 “peculiar galaxies,” put together by astronomer Halton Arp in 1966. From the caption:

The larger galaxy (in the left of this image) is an extremely energetic galaxy type known as a Seyfert galaxy, which house active galactic nuclei at their cores. Seyfert galaxies are notable because despite the immense brightness of the active core, radiation from the entire galaxy can be observed. This is evident in this image, where the spiraling whorls of the whole galaxy are readily visible. The smaller companion is connected to the larger by a tenuous-seeming ‘bridge’, composed of dust and gas. The colliding galactic duo lie about 465 million light-years from Earth.

Note that if you ignore the blue whorls of the left galaxy, the two bright cores of these merging galaxies are about the same size. As it is unclear how long this merger has been on-going, it is possible that the galaxy on the right, in circling the left galaxy, drew out those whorls and that tenuous bridge. Other scenarios are also possible, however, such as the galaxy on the left stripping and scattering the arms of the galaxy on the right.

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A galactic cloud

9:27 am

A galactic cloud
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Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken by the Hubble Space Telescope. It shows what scientists dub a lenticular galaxy, with features that put it somewhere between a spiral galaxy and an elliptical (which has no structure a appears instead a cloud of stars), sitting about 73 million light years away.

NGC 3156 has been studied in many ways … from its cohort of globular clusters, to its relatively recent star formation, to the stars that are being destroyed by the supermassive black hole at its centre.

Why this galaxy has no spiral arms is somehow related to its age and its central black hole, but the detailed theories that astronomers have to explain this are far from confirmed.

The image is interesting also because of its lack of foreground stars or background galaxies. Its location in the sky explains this, as Hubble was looking at right angle to the Milky Way’s galactic plane, essentially looking directly into the vast emptiness between the galaxies.

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A triangular spiral galaxy

9:25 am

A triangular spiral galaxy
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Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken by the Hubble Space Telescope as part of a follow-up observations of a supernova that occurred in this galaxy in 2015. The galaxy, dubbed IC 1776, is about 150 million light years away.

Hubble investigated the aftermath of the supernova SN 2015ap during two different observing programmes, both designed to comb through the debris left by supernovae explosions in order to better understand these energetic events. A variety of telescopes automatically follow up the detection of supernovae to obtain early measurements of these events’ brightnesses and spectra. Complementing these measurements with later observations which reveal the lingering energy of supernovae can shed light on the systems which gave rise to these cosmic cataclysms in the first place.

As the caption notes, the spiral arms of this galaxy “are difficult to distinguish.” At first glance the galaxy instead appears triangular in shape, an impression that dissolves with a closer look.

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A ghostly bullseye galaxy

11:18 am

A ghostly bullseye
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A cool image to start the week! The picture to the right, cropped and reduced to post here, was taken by the Hubble Space Telescope as part of a survey scientists are doing using Hubble, attempting to get high resolution images of every galaxy within about 30 million light years of the Milky Way. Prior to this census Hubble had covered about 75% of these galaxies. This particular galaxy is called a lenticular galaxy.

Lenticular galaxies like NGC 6684 (lenticular means lens-shaped) possess a large disc but lack the prominent spiral arms of galaxies like the Andromeda Galaxy. This leaves them somewhere between elliptical galaxies and spiral galaxies, and lends these galaxies a diffuse, ghostly experience. NGC 6684 also lacks the dark dust lanes that thread through other galaxies, adding to its spectral, insubstantial appearance.

The unknown is whether this is the state of a galaxy prior to becoming a spiral, or it is what it looks like as it transitions from a spiral to an elliptical. This particular galaxy is likely the latter, as it lacks the dust, but this does not have to be the rule.

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Spirals within spirals

8:58 am

Spirals within spirals
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Cool image time! The picture to the right, cropped, reduced, and annotated to post here, was taken by the Hubble Space Telescope as part of two different research projects that are studying galaxies where supernovae previously occurred. This particular galaxy is estimated to be about 192 million light years away, and is a classic example of a barred spiral.

Despite appearing as an island of tranquillity in this image, UGC 12295 played host to a catastrophically violent explosion — a supernova — that was first detected in 2015. This supernova prompted two different teams of astronomers to propose Hubble observations of UGC 12295 that would sift through the wreckage of this vast stellar explosion.

Supernovae are the explosive deaths of massive stars, and are responsible for forging many of the elements found here on Earth. The first team of astronomers used Hubble’s Wide Field Camera 3 (WFC3) to examine the detritus left behind by the supernova in order to better understand the evolution of matter in our Universe.

The second team of astronomers also used WFC3 to explore the aftermath of UGC 12295’s supernova, but their investigation focused on returning to the sites of some of the best-studied nearby supernovae. Hubble’s keen vision can reveal lingering traces of these energetic events, shedding light on the nature of the systems that host supernovae.

What struck me about this picture however were the many smaller spiral galaxies scattered nearby and behind UGC 12295, with one face-on spiral highlighted near the top. I can count at least three or four other background spiral galaxies, all reddish in color likely because their light has been shifted to the red due to their distance.

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A spiral galaxy as seen by Hubble

9:40 am

A spiral galaxy as seen by Hubble
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Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken as part of a research project to use the Hubble Space Telescope to photograph galaxies where supernovae had recently occurred. From the caption:

UGC 11860 lies around 184 million light-years away in the constellation Pegasus, and its untroubled appearance can be deceiving; this galaxy recently played host to an almost unimaginably energetic stellar explosion.

A supernova explosion — the catastrophically violent end of a massive star’s life — was detected in UGC 11860 in 2014 by a robotic telescope dedicated to scouring the skies for transient astronomical phenomena; astronomical objects which are only visible for a short period of time. Two different teams of astronomers used Hubble’s Wide Field Camera 3 to search through the aftermath and unpick the lingering remnants of this vast cosmic explosion.

This Hubble image once again illustrates the vastness of the universe. Note that every single dot surrounding UGC 11860 in this picture is another far more distant galaxy. As much as UGC 11860 is in our local intergalactic neighborhood, it is still so distant that this field of view is small enough that it contains no stars.

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A faint irregular cloud of stars

9:06 am

A faint irregular cloud of stars
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Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was released today by the science team of the Hubble Space Telescope. It shows an irregular galaxy thought to be about 44 million light years away.

Alongside its hazy shape, NGC 7292 is remarkably faint. As a result, astronomers classify NGC 7292 as a low surface brightness galaxy, barely distinguishable against the backdrop of the night sky. Such galaxies are typically dominated by gas and dark matter rather than stars.

Astronomers directed Hubble to inspect NGC 7292 during an observational campaign studying the aftermath of Type II supernovae. These colossal explosions happen when a massive star collapses and then violently rebounds in a catastrophic explosion that tears the star apart. Astronomers hope to learn more about the diversity of Type II supernovae they have observed by scrutinising the aftermath and remaining nearby stars of a large sample of historical Type II supernovae.

NGC 7292’s supernova was observed in 1964 and accordingly given the identifier SN 1964H. Studying the stellar neighbourhood of SN 1964H helps astronomers estimate the initial mass of the star that went supernova, and could uncover surviving stellar companions that once shared a system with the star that would become SN 1964H.

I searched but was unable to locate any 1964 images of this galaxy when the supernova was still visible, so I could not pinpoint its location in the picture. It has long since faded away.

Note that the reddish smudges scattered throughout the picture are likely galaxies so far distant that their light has shifted entirely into the reddish spectrum. This likely places them one to several billions of light years away, not millions.

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Hubble snaps picture of another jellyfish galaxy

10:05 am

Another jellyfish galaxy
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Astronomers today released another picture of a jellyfish galaxy taken by the Hubble Space Telescope, with that picture to the right, cropped, reduced, and sharpened to post here. From the caption:

The jellyfish galaxy JO206 trails across this image from the NASA/ESA Hubble Space Telescope, showcasing a colourful star-forming disc surrounded by a pale, luminous cloud of dust. A handful of bright stars with criss-cross diffraction spikes stand out against an inky black backdrop at the bottom of the image. JO206 lies over 700 million light-years from Earth in the constellation Aquarius.

This image is the sixth and final such photograph in this survey. You can view all of these images here. The study has found that star formation does not seem to be significantly different inside the galaxy versus the tentacles that stretch out beyond due to pressure from the intergalactic material. This suggests that the influence of this intergalactic material on the formation of stars is relatively minor.

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Jellyfish galaxy plowing its way through the intercluster medium

10:01 am

Jellyfish galaxy plowing through the intercluster medium
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The European Space Agency (ESA) today released another in a series of images taken by the Hubble Space Telescope during the past two years of what astronomers call jellyfish galaxies, so named because such galaxies have tendrils that extend out beyond the galaxy like the tendrils of jellyfish. This new picture is to the right, cropped, reduced, and sharpened to post here, and shows a galaxy about 900 million light years away.

[T]he space between galaxies in a cluster is … pervaded with a searingly hot plasma known as the intracluster medium. While this plasma is extremely tenuous, galaxies moving through it experience it almost like swimmers fighting against a current, and this interaction can strip galaxies of their star-forming gas. This interaction between the intracluster medium and the galaxies is called ram-pressure stripping, and is the process responsible for the trailing tendrils of this jellyfish galaxy.

The arrow in the image indicates the galaxy’s direction of travel through the intercluster medium, resulting in the outer parts of the leading arm to be pushed backward above the galaxy, while material at its rear trail behind. Note also the blue star-forming regions at the galaxy’s bow. The ram pressure is also apparently causing more star formation in this part of the galaxy compared to elsewhere.

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Momentus and Astroscale team up to propose Hubble servicing mission

11:29 am

Capitalism in space: The two orbital tug companies Momentus and Astroscale announced today that they have partnered to propose a servicing mission to the Hubble Space Telescope, designed to boost the telescope and extend its life.

The proposed mission concept, a commercial solution to extend the life of this important national asset without risk to humans, includes launching a Momentus Vigoride Orbital Service Vehicle (OSV) to low-Earth orbit on a small launch vehicle. Once on orbit, Astroscale’s RPOD technology built into the OSV would be used to safely rendezvous, approach and then complete a robotic capture of the telescope. Once mated, the OSV would perform a series of maneuvers to raise the Hubble by 50 km. Removal of surrounding and threatening space debris in Hubble’s new orbit using the Vigoride and Astroscale’s RPOD capabilities will be prioritized after the completion of the primary reboost mission.

As I have written repeatedly, Hubble is a telescope that refuses to die. I predicted that come the 2030s, when its orbit had decayed to a point that it either had to be de-orbited (NASA’s preferred option in the past when it ran everything) or be lifted to a higher orbit to extend its life, people would find a way to lift it.

Now that private enterprise is running the show, NASA is taking advantage of that to ask for private solutions to save Hubble, and not surprisingly it is quickly getting them.

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Hubble captures shadows on star’s outer accretion disk cast by inner accretion disk

11:07 am

Shadows cast on star's accretion disk
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Astronomers using the Hubble Space Telescope’s images taken five years apart have captured the changing shadows cast by a star’s inner accretion disk onto its outer accretion disk.

Those images are to the right, reduced and rearranged to post here. From the caption:

Comparison images from the NASA/ESA Hubble Space Telescope, taken several years apart, have uncovered two eerie shadows moving counterclockwise across a disc of gas and dust encircling the young star TW Hydrae. The discs are tilted face-on as seen from Earth and so give astronomers a bird’s-eye view of what’s happening around the star.

The [top] image, taken in 2016, shows just one shadow [A] at the 11 o’clock position. This shadow is cast by an inner disc that is slightly inclined to the outer disc and so blocks starlight. The picture on the [bottom] shows a second shadow that emerged from yet another nested disc at the 7 o’clock position, as photographed in 2021. What was originally the inner disc is marked [B] in this later view.

The shadows rotate around the star at different rates like the hand on a clock. They are evidence for two unseen planets that have pulled dust into their orbits. This makes them slightly inclined to each other. This is a visible-light photo taken with the Space Telescope Imaging Spectrograph. Artificial colour has been added to enhance details.

An artist’s conception of the system, as seen from an oblique angle, is available here. All told, this solar system of disks kind of resembles a spinning gyroscope, with its different rings tilted at different angles to conserve angular momentum.

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Two interacting galaxies, both with active supermassive black holes at their center

10:20 am

Interacting galaxies
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Cool image time! The picture to the right, cropped and reduced to post here, was taken by the Hubble Space Telescope and released today. From the caption:

This new image from NASA’s Hubble Space Telescope shows interacting galaxies known as AM 1214-255. These galaxies contain active galactic nuclei, or AGNs. An AGN is an extraordinarily luminous central region of a galaxy. Its extreme brightness is caused by matter whirling into a supermassive black hole at the galaxy’s heart.

Hubble observed the galaxy [on the right] as part of an AGN survey, with the aim of compiling a dataset about nearby AGNs to be used as a resource for astronomers investigating AGN physics, black holes, host galaxy structure, and more.

Note how the outer arms of both galaxies appear warped, with long streams of stars being pulled towards the other galaxy. Imagine living on a planet orbiting one of those stars as it finds itself over time farther and farther from its home galaxy, out in the vast emptiness of intergalactic space. While this sounds lonely, it has advantages for life, because isolated from the galaxy the star will not be threatened by supernovae, gamma ray bursts, and the host of other events that happen inside galaxies that can threaten biology.

It also means your night sky will be heralded by the rising and setting of two nearby giant galaxies.

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A nearby aging galaxy with an active supermassive black hole at its center

9:44 am

aging galaxy
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Cool image time! The picture to the right, reduced and sharpened to post here, was taken by the Hubble Space Telescope and released today. It shows a galaxy only 30 million light years away, making almost our neighbor. From the caption:

NGC 3489 has an active galactic nucleus, or AGN. The AGN sits at the center of the galaxy, is extremely bright, and emits radiation across the entire electromagnetic spectrum as the black hole devours material that gets too close to it.

This lenticular galaxy is a Seyfert galaxy, which is a class of AGN that is dimmer than other types of AGNs. They generally don’t outshine the rest of the galaxy, so the galaxy surrounding the black hole is clearly visible. Other types of AGNs emit so much radiation that it is almost impossible to observe the host galaxy.

That active nucleus is the bright dominate sphere at the galaxy’s center, large enough to overwhelm a large percentage of the rest of the galaxy. Its existence and dominance suggests that this galaxy is aging, and is beginning the transition from a spiral to an elliptical. In fact, its arms have already mostly vanished, and there is at present little star-formation on-going.

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Galaxies without end

9:44 am

Galaxies without end
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Cool image time! The picture to the right has been significantly reduced but also significantly sharpened to post here. It was taken by the Hubble Space Telescope as part of a recent survey of “jellyfish” galaxies, galaxies located in galaxy clusters where there is a large concentration of galaxies whose combined gravity and intergalactic environment acts to pull material or “tendrils” out from the galaxy.

Rather than crop the image to focus on that single large central jellyfish galaxy, I have instead sharpened the much-reduced full photo to bring out clearly the number of surrounding galaxies. There is only one Milky Way star in this picture, the object with the four diffraction spikes in the lower-right. Every other dot is a galaxy, many of which can be seen to be very strangely shaped in the original full resolution image. In fact, I strongly recommend you click on the picture to explore that original image, just to see the variety of galaxy shapes.

The point of this picture today however is not to illustrate the wide variety of galaxies that can exist, but to underline the vast and largely incomprehensible scale of the universe. The large galaxy is thought to be 650 million light years away, which means it took light traveling at 186,000 miles per second that many years to get here. The surrounding galaxies are also all tens to hundreds of millions of light years from each other. Yet, their combined gravity, almost infinitesimal in strength, is enough to warp the shape of each.

We understand these numbers and facts intellectually, but do we understand them in reality? I think it is difficult, even if you work hard to come up with a scaled comparison. For example, it took nine years for the New Horizons spacecraft to get from Earth to Pluto, a distance of about 4.5 light hours. And New Horizons was the fastest traveling probe ever launched, moving at 36,400 miles per hour when it left Earth. Yet, this distance is nothing compared to the distance between these galaxies.

The vastness of existence really is beyond our comprehension. That we try to comprehend it speaks well of the human desire to achieve the impossible.

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A classic spiral galaxy

11:06 am

A classic spiral galaxy
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Cool image time! The photo to the right, cropped, reduced, and sharpened to post here, was taken by the Hubble Space Telescope and released today as the European Space Agency’s (ESA) Hubble picture of the week.

A large spiral galaxy. It has many narrow arms that are tightly-twisted in the centre, but at the ends they point out in different directions. The galaxy’s core glows brightly, while its disc is mostly faint, but with bright blue spots throughout the arms. A few smaller spiral galaxies at varying angles are visible in front, and it is surrounded by other tiny stars and galaxies, on a black background.

This galaxy is believed to be 260 million light years away, and was home to a supernova in 2020. This image was taken as a follow-up to that explosion.

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Webb snaps infrared picture of Uranus

10:11 am

Uranus as seen in the infrared by Webb
Click for original Webb false-color image.

In a follow-up to a recent Hubble Space Telescope optical image of Uranus, scientists have now used the Webb Space Telescope to take a comparable picture in the infrared of the gas giant.

Both pictures are to the right, with the Webb picture at the top including the scientists’ annotations.

On the right side of the planet there’s an area of brightening at the pole facing the Sun, known as a polar cap. This polar cap is unique to Uranus – it seems to appear when the pole enters direct sunlight in the summer and vanish in the fall; these Webb data will help scientists understand the currently mysterious mechanism. Webb revealed a surprising aspect of the polar cap: a subtle enhanced brightening at the center of the cap. The sensitivity and longer wavelengths of Webb’s NIRCam may be why we can see this enhanced Uranus polar feature when it has not been seen as clearly with other powerful telescopes like the Hubble Space Telescope and Keck Observatory.

At the edge of the polar cap lies a bright cloud as well as a few fainter extended features just beyond the cap’s edge, and a second very bright cloud is seen at the planet’s left limb. Such clouds are typical for Uranus in infrared wavelengths, and likely are connected to storm activity.

The Webb image also captures 11 of Uranus’s 13 rings, which appear much brighter in the infrared than in the optical.

Unlike all other planets in the solar system, Uranus’s rotation is tilted so much that it actually rolls as it orbits the Sun, a motion that is obvious by comparing these pictures with Hubble’s 2014 optical picture.

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A multitude of strange galaxies

11:57 am

A multitude of strange galaxies
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Cool image time! The picture to the right, reduced and sharpened to post here, was taken by the Hubble Space Telescope and released today. From the caption:

Z 229-15 is one of those interesting celestial objects that, should you choose to research it, you will find defined as several different things: sometimes as an active galactic nucleus (an AGN); sometimes as a quasar; and sometimes as a Seyfert galaxy. Which of these is Z 229-15 really? The answer is that it is all of these things all at once, because these three definitions have significant overlap.

All three classifications involve galaxies with nuclei that are brighter, more energetic, and more massive than the rest of the galaxy. Z229-15 itself is estimated to be 390 million light years away.

Normally I would have cropped the image to center on Z229-15. However, I was struck by the number of other strange galaxies in the distance and on the periphery of the picture. Near the top is a trio of three, none of which appear spiral- or elliptical-shaped. On the right is a galaxy that could be a standard spiral seen edge-on, but its red nucleus is very unusual. And scattered across the bottom half of the image are a number of weirdly shaped galaxies of all types, none of which appear typical.

Be sure to look at the high resolution original. There are more weird galaxies visible there.

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Hubble spots long term seasonal changes on Uranus

10:20 am

Uranus as seen by Hubble in 2014 and 2022
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Using images of Uranus taken eight years apart by the Hubble Space Telescope, astronomers have detected significant seasonal changes in the atmosphere of the gas giant, caused by its unusual sideways rotation.

The two pictures to the left, realigned and reduced to post here, show the changes. If you look closely you can see the planet’s ring system and its shift to almost face on at present.

[top] — This is a Hubble view of Uranus taken in 2014, seven years after northern spring equinox when the Sun was shining directly over the planet’s equator, and shows one of the first images from the OPAL program. Multiple storms with methane ice-crystal clouds appear at mid-northern latitudes above the planet’s cyan-tinted lower atmosphere. Hubble photographed the ring system edge-on in 2007, but the rings are seen starting to open up seven years later in this view. At this time, the planet had multiple small storms and even some faint cloud bands.

[bottom] — As seen in 2022, Uranus’ north pole shows a thickened photochemical haze that looks similar to the smog over cities. Several little storms can be seen near the edge of the polar haze boundary. Hubble has been tracking the size and brightness of the north polar cap and it continues to get brighter year after year. Astronomers are disentangling multiple effects – from atmospheric circulation, particle properties, and chemical processes – that control how the atmospheric polar cap changes with the seasons. At the Uranian equinox in 2007, neither pole was particularly bright.

To really understand the long term climate of Uranus will likely take centuries, since its year lasts 84 Earth years. Since the beginning of space exploration, we have only had now about forty years of good imagery of the planet, and even that has been sporadic and very incomplete.

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Blobs and jellyfish in space

10:00 am

Blobs and Jellyfish
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Cool image time! The picture to the right, cropped and reduced to post here, was taken by the Hubble Space Telescope and released today.

The galaxy JW100 features prominently in this image from the NASA/ESA Hubble Space Telescope, with streams of star-forming gas dripping from the disc of the galaxy like streaks of fresh paint. These tendrils of bright gas are formed by a process called ram pressure stripping, and their resemblance to dangling tentacles has led astronomers to refer to JW100 as a ‘jellyfish’ galaxy. It is located in the constellation Pegasus, over 800 million light-years away.

Ram pressure stripping occurs when galaxies encounter the diffuse gas that pervades galaxy clusters. As galaxies plough through this tenuous gas it acts like a headwind, stripping gas and dust from the galaxy and creating the trailing streamers that prominently adorn JW100. The bright elliptical patches in the image are other galaxies in the cluster that hosts JW100.

The image was part of a research project studying star formation in the tendrils of jellyfish galaxies.

The blob near the top of the image is another galaxy in this same galaxy cluster. It is an elliptical galaxy that also happens to have two central nuclei, caused when two smaller galaxies merged. The central regions of each have not yet merged into one.

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Hubble looks at a nearby dwarf galaxy

9:38 am

A nearby dwarf galaxy
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Cool image time! The photo to the right, cropped, reduced, and sharpened to post here, was taken by the Hubble Space Telescope as part of a continuing project to capture high resolution images of every nearby galaxy, which in this particular case the caption describes as follows:

UGCA 307 hangs against an irregular backdrop of distant galaxies in this image from the NASA/ESA Hubble Space Telescope. The small galaxy consists of a diffuse band of stars containing red bubbles of gas that mark regions of recent star formation, and lies roughly 26 million light-years from Earth in the constellation Corvus. Appearing as just a small patch of stars, UGCA 307 is a diminutive dwarf galaxy without a defined structure — resembling nothing more than a hazy patch of passing cloud.

The red regions of star formation are significant, as they indicate that even in a tiny galaxy like this it is possible for there to be enough gas and dust to coalesce into new stars.

Astronomers living on a world inside this galaxy have an advantage over astronomers on Earth. There is no large galaxy like the Milky Way blocking their view of the cosmos in one direction. They can see it all, even in directions looking through UGCA 307.

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A confused spiral galaxy

10:34 am

An irregular spiral galaxy

Cool image time! The picture to the right, cropped and reduced to post here, was taken by the Hubble Space Telescope and released today. From the caption:

The irregular spiral galaxy NGC 5486 hangs against a background of dim, distant galaxies in this image from the NASA/ESA Hubble Space Telescope. The tenuous disc of the galaxy is threaded through with pink wisps of star formation, which stand out from the diffuse glow of the galaxy’s bright core. While this particular galaxy has indistinct, meandering spiral arms it lies close to the much larger Pinwheel Galaxy, one of the best known examples of ‘grand design’ spiral galaxies with prominent and well-defined spiral arms. In 2006 Hubble captured an image of the Pinwheel Galaxy which was — at the time — the largest and most detailed photo of a spiral galaxy ever taken with Hubble.

This galaxy is defined I think as an irregular spiral because if you look close, you can see a very faint hint of a central bar and two large arms spiraling away at its ends. It is faint however, and might simply be caused by the human mind’s natural desire to see patterns. To my eye this galaxy could just as well be a patchy elliptical galaxy, with no arms at all.

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Galaxies afloat in space

10:00 am

Galaxies afloat in space
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Cool image time! The picture to the right, cropped and reduced to post here, was taken by the Hubble Space Telescope and released today. It is part of a survey project studying what the press release calls “jellyfish galaxies,” spiral galaxies that have long extended arms.

As jellyfish galaxies move through intergalactic space they are slowly stripped of gas, which trails behind the galaxy in tendrils illuminated by clumps of star formation. These blue tendrils are visible drifting below the core of this galaxy, and give it its jellyfish-like appearance. This particular jellyfish galaxy — known as JO201 — lies in the constellation Cetus, which is named after a sea monster from ancient Greek mythology. This sea-monster-themed constellation adds to the nautical theme of this image.

On the lower left is what the press release calls an elliptical galaxy, probably because it has no obvious arms. It is however shaped more like a spiral galaxy, since ellipticals tend to be spherical. If you look close you will also notice at least five-plus other galaxies in this picture, all smaller either because they are much farther away or are simply much smaller.

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Trio of colliding galaxies

9:32 am

Trio of colliding galaxies
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Cool image time! The picture above, cropped and reduced to post here, was taken by the Hubble Space Telescope and released today. From the caption:

Three galaxies stand together just right of centre. They are close enough that they appear to be merging into one. Their shapes are distorted, with strands of gas and dust running between them. Each is emitting a lot of light. Further to the left is an unconnected, dimmer spiral galaxy. The background is dark, with a few smaller, dim and faint galaxies and a couple of stars.

Astronomers estimate the colliding galaxies are about 50,000 light years from each other, which for galaxies is quite close. Eventually gravity will cause all three to merge into a single very large galaxy, its shape distorted by the merger. What that shape will be is one of the things astronomers are trying to figure out. At present their theories for galaxy evolution states that as galaxies grow by absorbing smaller nearby neighbors, they evolve from spirals to ellipticals, giant blobs lacking a distinct obvious structure.

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Two nearby galactic neighbors

11:46 am

Two nearby galactic neighbors
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Cool image time! The photo to the right, cropped, reduced, and sharpened to post here, was taken by the Hubble Space Telescope of two nearby galaxy neighbors to the Milky way.

This image from the NASA/ESA Hubble Space Telescope features the galaxy LEDA 48062 in the constellation Perseus. LEDA 48062 is the faint, sparse, amorphous galaxy on the right side of this image, and it is accompanied by a more sharply defined neighbour on the left, the large, disc-like lenticular galaxy UGC 8603. A smattering of more distant galaxies also litter the background, and a handful of foreground stars are also visible throughout the image.

LEDA 48062 is estimated to be approximately 30 million light years away. This image was part of a recent Hubble campaign to study every known galaxy within 33 million light years.

Assuming that UGC 8603 is about the same approximate distance, the utter dissimilarity between these two galaxies is quite mystifying. It is also possible that UGC 8603 is larger and much farther away.

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A long-armed galaxy

8:51 am

Galaxy with long and faint tidal streams
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Cool image time! The photo to the right, cropped, enhanced, and reduced to post here, was taken by the Hubble Space Telescope as part of a survey of peculiar looking galaxies.

The peculiar spiral galaxy ESO 415-19, which lies around 450 million light-years away, stretches lazily across this image from the NASA/ESA Hubble Space Telescope. While the centre of this object resembles a regular spiral galaxy, long streams of stars stretch out from the galactic core like bizarrely elongated spiral arms. These are tidal streams caused by some chance interaction in the galaxy’s past, and give ESO 415-19 a distinctly peculiar appearance.

ESO 415-19’s peculiarity made it a great target for Hubble. This observation comes from an ongoing campaign to explore the Arp Atlas of Peculiar Galaxies, a menagerie of some of the weirdest and most wonderful galaxies that the Universe has to offer. These galaxies range from bizarre lonesome galaxies to spectacularly interacting galaxy pairs, triplets, and even quintets. These space oddities are spread throughout the night sky, which means that Hubble can spare a moment to observe them as it moves between other observational targets.

I have intentionally brightened the galaxy to make the two faint two tidal streams more obvious. That they are so faint compared to the galaxy itself is in itself a mystery.

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NASA requesting proposals for raising Hubble’s orbit

9:23 am

NASA has published a request for proposals from the private commercial space industry for a possible future mission to raise Hubble’s orbit.

NASA published a request for information (RFI) Dec. 22 asking industry how they would demonstrate commercial satellite servicing capabilities by raising the orbit of Hubble. The agency said it is looking for technical information about how a company would carry out the mission, the risks involved and the likelihood of success.

NASA emphasized in the RFI that it had no plans to procure a mission to reboost Hubble. “Partner(s) would be expected to participate and undertake this mission on a no-exchange-of-funds basis,” the document stated, with companies responsible for the cost for the mission.

Apparently, this RFI was issued as a direct result of the agreement between NASA and SpaceX to study a Dragon mission to do exactly this, which in turn was prompted by Jared Isaacman, as part of his private Polaris program of manned Dragon/Starship space flights. I suspect that NASA officials realized that not only were their engineering advantages to getting more proposals, there were probably legal and political reasons for opening the discussion up to the entire commercial space community.

Ideally, a Hubble reboost mission should occur by 2025, though the telescope’s orbit will remain stable into the mid-2030s.

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Blobs in space

11:42 am

Blobs in space
Click for full image.

Cool image time! The photo to the right, cropped and reduced to post here, was taken by the Hubble Space Telescope and released today by the science team. From the caption:

This image shows a small region of the well-known nebula Westerhout 5, which lies about 7000 light-years from Earth. Suffused with bright red light, this luminous image hosts a variety of interesting features, including a free-floating Evaporating Gaseous Globule (frEGG). The frEGG in this image is the small tadpole-shaped dark region in the upper left. This buoyant-looking bubble is lumbered with two rather uninspiring names — [KAG2008] globule 13 and J025838.6+604259.

FrEGGs are a particular class of Evaporating Gaseous Globules (EGGs). Both frEGGs and EGGs are regions of gas that are sufficiently dense that they photoevaporate less easily than the less compact gas surrounding them. Photoevaporation occurs when gas is ionised and dispersed away by an intense source of radiation — typically young, hot stars releasing vast amounts of ultraviolet light. EGGs were only identified fairly recently, most notably at the tips of the Pillars of Creation, which were captured by Hubble in iconic images released in 1995. FrEGGs were classified even more recently, and are distinguished from EGGs by being detached and having a distinct ‘head-tail’ shape. FrEGGs and EGGs are of particular interest because their density makes it more difficult for intense UV radiation, found in regions rich in young stars, to penetrate them. Their relative opacity means that the gas within them is protected from ionisation and photoevaporation. This is thought to be important for the formation of protostars, and it is predicted that many FrEGGs and EGGs will play host to the birth of new stars.

The bright red edges of these blobs are places where ionization is occurring, which tells us that the young hot star causing it is to the top, beyond the edge of the picture. Its radiation is also likely causing the blob’s tabpole shape as material is pushed downward away from the star.

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A barred spiral galaxy with distorted galaxy

10:58 am

A barred spiral galaxy
Click for full image.

Cool image time! The photo to the right, reduced and cropped to post here, was taken by the Hubble Space Telescope and shows a barred spiral galaxy about 214 million light years away.

Scientists used NASA’s Hubble Space Telescope to image NGC 6956 to study its Cepheid variable stars, which are stars that brighten and dim at regular periods. Since the period of Cepheid variable stars is a function of their brightness, scientists can measure how bright these stars appear from Earth and compare it to their actual brightness to calculate their distance. As a result, these stars are extremely useful in determining the distance of cosmic objects, which is one of the hardest pieces of information to measure for extragalactic objects.

The press release of course focuses on this magnificent barred spiral. I however want to draw your attention to the smaller galaxy in the white box.

background distorted galaxy

Since we do not know the distance to this distorted galaxy, we do not know if its distortion is caused by the barred spiral. It could be the bigger galaxy’s gravity is pulling material away.

More likely, based on the shape of this smaller galaxy, is that it is many light years farther away — which is why it looks so much smaller — and has been distorted because it is actually a collusion of two galaxies. The two bright nuclei with the red dust between strongly suggests such a collusion.

I highlight this background galaxy because it illustrates the importance when looking at any Hubble image to look at everything. To coin a phrase, there is gold in them thar hills, if you make the effort to look.

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A wall of smoke, as seen by Hubble

9:57 am

A wall of smoke, as seen by Hubble
Click for full image.

Using the Hubble Space Telescope, astronomers have produced a magnificent image of an interstellar cloud, cropped and reduced to post here. From the caption:

A portion of the open cluster NGC 6530 appears as a roiling wall of smoke studded with stars in this image from the NASA/ESA Hubble Space Telescope. NGC 6530 is a collection of several thousand stars lying around 4350 light-years from Earth in the constellation Sagittarius. The cluster is set within the larger Lagoon Nebula, a gigantic interstellar cloud of gas and dust. It is the nebula that gives this image its distinctly smokey appearance; clouds of interstellar gas and dust stretch from one side of this image to the other.

Astronomers investigated NGC 6530 using Hubble’s Advanced Camera for Surveys and Wide Field Planetary Camera 2. They scoured the region in the hope of finding new examples of proplyds, a particular class of illuminated protoplanetary discs surrounding newborn stars. The vast majority of proplyds have been found in only one region, the nearby Orion Nebula. This makes understanding their origin and lifetimes in other astronomical environments challenging.

The first proplyds were seen in the very first images taken by Hubble after it was fixed and could finally take sharp pictures. That so few have been seen since is thus somewhat surprising.

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