ESA/Hubble: Dotted across the sky in the constellation of Pictor (The Painter’s Easel) is the galaxy cluster highlighted here by the NASA/ESA Hubble Space Telescope: SPT-CL J0615-5746, or SPT0615 for short. First discovered by the South Pole Telescope less than a decade ago, SPT0615 is exceptional among the myriad clusters so far catalogued in our map of the Universe — it is the highest-redshift cluster for which a full, strong lens model is published.
SPT0615 is a massive cluster of galaxies, one of the farthest observed to cause gravitational lensing. Gravitational lensing occurs when light from a background object is deflected around mass between the object and the observer. Among the identified background objects, there is SPT0615-JD, a galaxy that is thought to have emerged just 500 million years after the Big Bang. This puts it among the very earliest structures to form in the Universe. It is also the farthest galaxy ever imaged by means of gravitational lensing.
Just as ancient paintings can tell us about the period of history in which they were painted, so too can ancient galaxies tell us about the era of the Universe in which they existed. To learn about cosmological history, astronomers explore the most distant reaches of the Universe, probing ever further out into the cosmos. The light from distant objects travels to us from so far away that it takes an immensely long time to reach us, meaning that it carries information from the past — information about the time at which it was emitted.
By studying such distant objects, astronomers are continuing to fill the gaps in our picture of what the very early Universe looked like, and uncover more about how it evolved into its current state.
Image: ESA/Hubble & NASA, I. Karachentsev et al., F. High et al.CC BY 4.0
NGC 2903 was discovered by William Hershel in 1784. Although this spiral galaxy was certainly bright enough to be seen by Charles Messier he never added it to his famous catalog. There is an entry for it in the SEDS site.
As for this lovely image from Hubble ESA writes:
Few of the Universe’s residents are as iconic as the spiral galaxy. These limelight-hogging celestial objects combine whirling, pinwheeling arms with scatterings of sparkling stars, glowing bursts of gas, and dark, weaving lanes of cosmic dust, creating truly awesome scenes — especially when viewed through a telescope such as the NASA/ESA Hubble Space Telescope. In fact, this image from Hubble frames a perfect spiral specimen: the stunning NGC 2903.
NGC 2903 is located about 30 million light-years away in the constellation of Leo (The Lion), and was studied as part of a Hubble survey of the central regions of roughly 145 nearby disc galaxies. This study aimed to help astronomers better understand the relationship between the black holes that lurk at the cores of galaxies like these, and the rugby-ball-shaped bulge of stars, gas, and dust at the galaxy’s centre — such as that seen in this image.
ESA: The Egg Nebula is a preplanetary nebula, created by a dying star in the process of becoming a planetary nebula. Planetary nebulas have nothing to do with planets – the name arose when 18th century astronomers spotted them in their telescopes and thought they looked like planets. Instead, they are the remnants of material expelled by Sun-like stars in the later stages of their lives.
The preplanetary nebula phase is extremely short-lived in astronomical terms – only a few thousand years. This makes them rare objects and, combined with the fact that they are quite faint, rather difficult to spot. The Egg Nebula, located around 3000 light years from us, was the first of its kind to be discovered in the 1970s. This image is based on observations performed in the mid 1990s by the Wide Field and Planetary Camera 2 (WFPC2) on the NASA/ESA Hubble Space Telescope.
During the preplanetary nebula phase, the central star periodically sheds its outer layers, which are then illuminated by the dying star at the centre. Eventually the star stops shedding material and the core remnant heats up, exciting the expelled gas so that it glows brightly and becomes a planetary nebula.
The dark band, sweeping beams, and criss-crossing arcs in this image can reveal a lot about the complex environment of a dying star. The central band is a cocoon of dust hiding the star from view.
Beams of light emanate from the obscured star, and it is thought that they are due to starlight escaping from the ring-shaped holes in the dusty cocoon that surrounds the star. The holes are possibly carved by a high-speed stream of matter, although the cause of these jets are unknown. The spoke-like features are shadows cast by blobs of material within the region of the holes in the cocoon.
Numerous bright arcs intersect the beams: these are shells of matter ejected by the star. The arcs are like tree rings, and can tell us something about the object’s age as they reveal that the rate of mass ejection has varied between 100 and 500 years throughout its 10 000 year history. The gas is expanding at a rate of 20 km/s and matter has been detected out to a radius of 0.6 light years, providing an estimate of the amount of matter in the nebula.
Image: R. Sahai and J. Trauger (JPL), the WFPC2 science team, and NASA/ESA
You can get a larger version by clicking the image above. ESA provided a link for a much larger image that I highly recommend you look at, it’s a little large (1.13 MB) and well worth the download.
Image: NASA, ESA, and STScI
ESA: This incredible image of the hourglass-shaped Southern Crab Nebula was taken to mark the NASA/ESA Hubble Space Telescope’s 29th anniversary in space. The nebula, created by a binary star system, is one of the many objects that Hubble has demystified throughout its productive life. This new image adds to our understanding of the nebula and demonstrates the telescope’s continued capabilities.
On 24 April 1990, the NASA/ESA Hubble Space Telescope was launched on the space shuttle Discovery. It has since revolutionised how astronomers and the general public see the Universe. The images it provides are spectacular from both a scientific and a purely aesthetic point of view.
Each year the telescope dedicates a small portion of its precious observing time to take a special anniversary image, focused on capturing particularly beautiful and meaningful objects. This year’s image is the Southern Crab Nebula, and it is no exception .
This peculiar nebula, which exhibits nested hourglass-shaped structures, has been created by the interaction between a pair of stars at its centre. The unequal pair consists of a red giant and a white dwarf. The red giant is shedding its outer layers in the last phase of its life before it too lives out its final years as a white dwarf. Some of the red giant’s ejected material is attracted by the gravity of its companion.
When enough of this cast-off material is pulled onto the white dwarf, it too ejects the material outwards in an eruption, creating the structures we see in the nebula. Eventually, the red giant will finish throwing off its outer layers, and stop feeding its white dwarf companion. Prior to this, there may also be more eruptions, creating even more intricate structures.
Astronomers did not always know this, however. The object was first written about in 1967, but was assumed to be an ordinary star until 1989, when it was observed using telescopes at the European Southern Observatory‘s La Silla Observatory. The resulting image showed a roughly crab-shaped extended nebula, formed by symmetrical bubbles of gas and dust.
These observations only showed the outer hourglass emanating from a bright central region that could not be resolved. It was not until Hubble observed the Southern Crab in 1999 that the entire structure came into view. This image revealed the inner nested structures, suggesting that the phenomenon that created the outer bubbles had occurred twice in the (astronomically) recent past.
It is fitting that Hubble has returned to this object twenty years after its first observation. This new image adds to the story of an active and evolving object and contributes to the story of Hubble’s role in our evolving understanding of the Universe.
 The Southern Crab Nebula is so named to distinguish it from the better-known Crab Nebula, a supernova remnant visible in the constellation of Taurus.
Hubble et. al: Star clusters are commonly featured in cosmic photoshoots, and are also well-loved by the keen eye of the NASA/ESA Hubble Space Telescope. These large gatherings of celestial gems are striking sights — and Messier 2 is certainly no exception.
Messier 2 is located in the constellation of Aquarius (the Water Bearer), about 55,000 light-years away. It is a globular cluster, a spherical group of stars all tightly bound together by gravity. With a diameter of roughly 175 light-years, a population of 150,000 stars, and an age of 13 billion years, Messier 2 is one of the largest clusters of its kind and one of the oldest associated with the Milky Way.
This Hubble image of Messier 2’s core was created using visible and infrared light. Most of the cluster’s mass is concentrated at its center, with shimmering streams of stars extending outward into space. It is bright enough that it can even be seen with the naked eye when observing conditions are extremely good.
The Wild Duck Cluster also known as Messier 11 in the famous catalog by Charles Messier. It’s in a fun area of the sky for viewing, Of course we won’t see it like this look from Hubble, but it’s an excellent area to peruse.
Hubble (et. al.): This star-studded image shows us a portion of Messier 11, an open star cluster in the southern constellation of Scutum (the Shield). Messier 11 is also known as the Wild Duck Cluster, as its brightest stars form a “V” shape that somewhat resembles a flock of ducks in flight.
Messier 11 is one of the richest and most compact open clusters currently known. By investigating the brightest, hottest main sequence stars in the cluster, astronomers estimate that it formed roughly 220 million years ago. Open clusters tend to contain fewer and younger stars than their more compact globular cousins, and Messier 11 is no exception: at its center lie many blue stars, the hottest and youngest of the cluster’s few thousand stellar residents.
The lifespans of open clusters are also relatively short compared to those of globular ones; stars in open clusters are spread farther apart and are thus not as strongly bound to each other by gravity, causing them to be more easily and quickly drawn away by stronger gravitational forces. As a result, Messier 11 is likely to disperse in a few million years as its members are ejected one by one, pulled away by other celestial objects in the vicinity.
Can you image being on a planet in either one of these colliding galaxies? One day in the very far future this might be a good analogy of our merging with the Andromeda galaxy. What would the sky look like, even in the daytime?
ESA: Located in the constellation of Hercules, about 230 million light-years away, NGC 6052 is a pair of colliding galaxies. They were first discovered in 1784 by William Herschel and were originally classified as a single irregular galaxy because of their odd shape. However, we now know that NGC 6052 actually consists of two galaxies that are in the process of colliding. This particular image of NGC 6052 was taken using the Wide Field Camera 3 on the NASA/ESA Hubble Space Telescope.
A long time ago gravity drew the two galaxies together into the chaotic state we now observe. Stars from within both of the original galaxies now follow new trajectories caused by the new gravitational effects. However, actual collisions between stars themselves are very rare as stars are very small relative to the distances between them (most of a galaxy is empty space). Eventually things will settle down and one day the two galaxies will have fully merged to form a single, stable galaxy.
Our own galaxy, the Milky Way, will undergo a similar collision in the future with our nearest galactic neighbour, the Andromeda Galaxy. Although this is not expected to happen for around 4 billion years so there is nothing to worry about just yet.
This object was previously observed by Hubble with its old WFPC2 camera. That image was released in 2015.
Image: ESA/Hubble & NASA, A. Adamo et al.; CC BY 4.0
Earth is not the only blue marble in the solar system, there is also Uranus (L) and Neptune (R).
Image: NASA, ESA, A. Simon (NASA Goddard Space Flight Center), and M.H. Wong and A. Hsu (University of California, Berkeley)
ESA: Sitting beyond Jupiter and Saturn in our Solar System, these two planets have only been visited once by a spacecraft, albeit briefly. NASA’s Voyager 2 spacecraft swung by Uranus in 1986, and Neptune in 1989, snapping the only close-up detailed images of these distant worlds.
The first images of Neptune revealed a planet with a dynamic atmosphere, including two mysterious dark vortices. Uranus, however, appeared featureless. But these views were just one-time snapshots: they couldn’t capture how the planets’ atmospheres change over time.
Enter the Hubble Space Telescope, which has been making a roughly annual check-up of these distant worlds as they go through protracted seasonal changes in their multi-decades-long orbits – a year on Uranus is 84 Earth years, while Neptune takes 165 of our years to orbit the Sun.
The latest pair of Hubble images are presented here, displaying Uranus (left) alive with activity and Neptune (right) showing off a new dark storm.
The vast bright polar cap across the north pole dominates the image of Uranus. The cap, which may form due to seasonal changes in atmospheric flow, has become much more prominent than in previous observations dating back to the Voyager 2 flyby, when the planet, in the throes of winter, looked bland.
Scientists believe this feature is a result of Uranus’ unique rotation. Unlike every other planet in the Solar System, Uranus is tipped over almost onto its side. Because of this extreme tilt, during the planet’s summer the Sun shines almost directly onto the north pole and never sets. Uranus is now approaching the middle of its 21 year-long summer season and the polar-cap region is becoming more prominent.
Near the edge of the cloud cap is a large cloud of methane ice, while a narrow cloud band encircles the planet north of the equator. It is a mystery how bands like these are confined to such narrow widths, because Uranus and Neptune have very broad westward-blowing wind jets.
The latest images show that Neptune has a new swirling dark storm spanning nearly 11 000 km across – roughly equivalent to the distance between Lisbon, Portugal and Tokyo, Japan. It is accompanied by bright white ‘companion clouds’ formed when the flow of ambient air is perturbed and diverted upward over the dark vortex, causing gases to freeze into methane ice crystals. Like Jupiter’s Great Red Spot, the dark vortices swirl in an anti-cyclonic direction and seem to dredge up material from deeper levels in the ice giant’s atmosphere.
Both Uranus and Neptune are classified as ‘ice giant’ planets, which are fundamentally different to the gas giants like Jupiter and Saturn. They have no solid surface but rather layers of hydrogen and helium surrounding a water-rich interior, itself perhaps wrapped around a rocky core. Atmospheric methane absorbs red light but allows blue-green light to be scattered back into space, giving each planet a characteristic cyan hue.
Analysing these worlds will help scientists better understand the diversity and similarities of the planets in our own Solar System as well as the thousands of exoplanets discovered in other solar systems – the vast majority of which fall into the size range of Neptune and Uranus.
Indeed, ESA’s upcoming exoplanet mission Cheops will focus on analysing stars that are known to host Earth to Uranus- and Neptune-sized planets, providing a first step-characterisation into the nature of these alien worlds.
Given a favourable alignment of Jupiter to provide gravity assists in the late 2020s-early 2030s, NASA and ESA have also been studying concepts to send a mission to the ice giants to better understand this little-understood class of planets.
These images were captured in late 2018 as part of the Outer Planet Atmospheres Legacy (OPAL) program, and first published on 7 February 2019. This caption is based on the original release.
Hubble Et al. – In this image, the NASA/ESA Hubble Space Telescope has captured the smoking gun of a newborn star, the Herbig–Haro objects numbered 7 to 11 (HH 7–11). These five objects, visible in blue in the top center of the image, lie within NGC 1333, a reflection nebula full of gas and dust found about a thousand light-years away from Earth.
Bright patches of nebulosity near newborn stars, Herbig-Haro objects like HH 7–11 are transient phenomena. Traveling away from the star that created them at a speed of up to about 150,000 miles per hour, they disappear into nothingness within a few tens of thousands of years. The young star that is the source of HH 7–11 is called SVS 13, and all five objects are moving away from SVS 13 toward the upper left. The current distance between HH 7 and SVS 13 is about 20,000 times the distance between Earth and the Sun.
Herbig–Haro objects are formed when jets of ionized gas ejected by a young star collide with nearby clouds of gas and dust at high speeds. The Herbig-Haro objects visible in this image are no exception to this and were formed when the jets from the newborn star SVS 13 collided with the surrounding clouds. These collisions created the five brilliant clumps of light within the reflection nebula.
ESA – This striking image combines data gathered with the Advanced Camera for Surveys, installed on the NASA/ESA Hubble Space Telescope and data from the Subaru Telescope in Hawaii. It shows just a part of the spectacular tail emerging from a spiral galaxy nicknamed D100.
Tails such as these are created by a process known as ram-pressure stripping. Despite appearances, the space between galaxies in a cluster is far from empty; it is actually filled with superheated gas and plasma, which drags and pulls at galaxies as they move through it, a little like the resistance one experiences when wading through deep water. This can be strong enough to tear galaxies apart, and often results in objects with peculiar, bizarre shapes and features — as seen here.
D100’s eye-catching tail of gas, which stretches far beyond this image to the left, is a particularly striking example of this phenomenon. The galaxy is a member of the huge Coma cluster. The pressure from the cluster’s hot constituent plasma (known as the intracluster medium) has stripped gas from D100 and torn it away from the galaxy’s main body, and drawing it out into the plume pictured here.
Densely populated clusters such as Coma are home to thousands of galaxies. They are thus the perfect laboratories in which to study the intriguing phenomenon of ram-pressure stripping, which, as well as producing beautiful images such as this, can have a profound effect on how galaxies evolve and form new generations of stars.