Arp 81


ARP81This distorted pair of galaxies is called Arp 81. About 100 million years ago, they had a close encounter, and the havoc wreaked by their mutual gravitational interaction resulted ing twisted streams of gas and dust, a chaos of massive star formation, and a tidal tail of debris stretching for a couple of hundred thousand light-years. NGC 6622 (left) and NGC 6621(right) are more of less equal in size. They are destined to merge into one larger galaxy in the distant future, after a mating dance of repeated approaches. The galaxies are 280,000,000 light-years away in the constellation Draco.

Image Credit: NASA

The Tadpole


The_TadpoleWhen I was a kid, one of the pleasures of spring was going to the creek and catching tadpoles. This bright blue tadpole seems to swim through the inky blackness of space. Catalogued as IRAS 20324+4057, “The Tadpole” is a clump of gas and dust giving birth to a bright protostar, one of the earliest steps in building a star.

There are multiple protostars in the tadpole’s head; the glowing yellow one in this image is the most luminous and massive. When this protostar has gathered together enough mass from its surroundings, it will become a fully-fledged young star.

The intense blue glow is caused by intense ultraviolet radiation from nearby stars. Pressure from that UV sculpts the tail into a long, wiggly shape. The Tadpole spans roughly a light-year from head to tail-tip, and contains gas with about four times the mass of the Sun.

Image Credit: NASA / ESA

A Horsehead of a Different Color


This video presents a visualization of the Horsehead Nebula as seen in infrared light. The central Hubble image has been augmented by ground-based observations from the European Southern Observatory’s Visible and Infrared Survey Telescope for Astronomy (VISTA). The stars distributed in the three-dimensional environment in an approximate and statistical manner. While it’s no 100%-accurate, the computer graphics are intended to be scientifically reasonable.

The Horsehead Nebula is a dark cloud of dense gas and dust located just below Orion’s belt. Visible light shows a strong silhouette resembling a horse’s head as used for a knight in chess. As seen at left with infrared light we can see more deeply into the clouds, revealing a more complex scene. The warm parts of the clouds glow in infrared light, and a dark and relatively featureless scene is revealed as a glowing gaseous landscape.

Video Credit: NASA

Breaking Up is Hard to Do


asteroid-disintegrationThis series of Hubble Space Telescope images shows the breakup of an asteroid over a period of several months beginning in late 2013. The largest fragments are up to 180 m in radius. The crumbling asteroid, designated P/2013 R3, was first noticed as an unusual, fuzzy-looking object by the Catalina and Pan STARRS sky surveys last September.

Image Credit: NASA

Confused Hubble


Confused HubbleHubble uses what is called its Fine Guidance System (FGS) in order to maintain stability while performing observations. A set of gyroscopes measures the attitude of the telescope, which is then corrected by a set of reaction wheels. In order to compensate for gyroscopic drift, the FGS locks onto a guide star as a fixed reference in space.

In this case, Hubble locked onto a bad guide star, probably a double star or binary, causing an error in the tracking system. The result was this remarkable picture of brightly colored stellar streaks. The prominent red streaks are from stars in the globular cluster NGC 288.

Image Credit: NASA / ESA

A Seyfert Galaxy


NGC 5793Carl Seyfert was an interesting fellow. Back in the ’50s when I was a kid growing up in Nashville, he was Director of the Dyer Observatory at Vanderbilt University. I met him through the local astronomy club associated with the Nashville Children’s Museum. He was well known around town because he moonlighted as the weatherman for WSM-TV. He was known in astronomical circles for his research on a class of galaxies.

Those galaxies have incredibly luminous centers that we believe are caused by supermassive black holes—black holes that can be billions of times the size of the sun—pulling in and swallowing gas and dust from their surroundings. NGC 5793 is a Seyfert galaxy over 150 million light-years away in the constellation of Libra.

This Hubble image is centered on NGC 5793. This galaxy is of great interest to astronomers for many reasons. For one, it appears to house objects known as masers. Whereas lasers emit visible light, masers emit microwave radiation. The term “maser” is an acronym of Microwave Amplification by Stimulated Emission of Radiation. Lasers emit visible light; masers emit microwave radiation. Maser emission occurs when particles absorb energy from their surroundings re-emit the energy in the microwave part of the spectrum. Naturally occurring masers such as are found in NGC 5793 can tell us a lot about their environment; we see some types of masers in areas where stars are forming. In NGC 5793 there are also intense mega-masers, thousands of times more luminous than the sun.

Image Credit: NASA

The Monkey Head Nebula


Monkey HeadThe Hubble Space Telescope captured a series of infrared-light images of a churning region of star birth 6,400 light-years away some of which have been stitched together in this mosaic of a small portion of the Monkey Head Nebula The cloud is sculpted by ultraviolet light eating into the cool hydrogen gas.

BTW, Hubble was launched 24 years ago.

Image Credit: NASA

Hubble Nets a Butterfly


Roberts22This cosmic butterfly is the nebula known as AFGL 4104 or Roberts 22. When a star that is nearing the end of its life throws off its outer layers, a nebula emerges as a cosmic chrysalis. Studies of the lobes of Roberts 22 show an amazingly complex structure with numerous intersecting loops and filaments.

A butterfly’s life span here on Earth is a few weeks. Roberts 22 is also transient but on a much longer time scale. It is currently a pre-planetary nebula, a brief phase that begins once a dying star has shed much of the material in its outer layers into space. That phase will end once this stellar remnant becomes hot enough to ionize the surrounding gas clouds causing them glow. About 400 years ago, the star at the center of Roberts 22 threw off its outer shells, forming this butterfly. Soon, on a cosmic scale, the central star will soon be hot enough to ionize the surrounding gas, and Roberts 22 will evolve into a fully-fledged planetary nebula.

Image Credit: NASA

Rotating a Galaxy


This animation illustrates the rotation rate of the Large Magellanic Cloud (LMC). Hubble Space Telescope observations have been used to determine that the central part of the LMC completes a rotation every 250 million years. It takes more than 10 million years for even the small amount of rotation illustrated in this video.

Video Credit: NASA

Antennae Galaxies


Antennae Galaxy Hubble_ALMAThe Antennae Galaxies (aka NGC 4038 and NGC 4039) are a distorted pair of colliding spiral galaxies about 70 million light-years away, in the constellation of Corvus (The Crow). This false color image combines observations made in two different millimeter wavelength ranges from the European Southern Observatory’s ALMA with visible light observations from the Hubble Space Telescope.

Visible light—shown here mainly in blue—reveals the newborn stars in the galaxies, ALMA’s view shows the clouds of dense cold gas from which new stars form. The ALMA observations—shown here in red, pink and yellow—were made at specific wavelengths of millimetre and submillimetre light,tuned to detect carbon monoxide molecules in the otherwise invisible hydrogen clouds, where new stars are forming. Massive concentrations of gas are found not only in the hearts of the two galaxies but also in the chaotic region where they are colliding. The total amount of gas is billions of times the mass of the Sun, a rich reservoir of material for future generations of stars.

Image Credit: NASA / ESA / ESO

Abell 2744 Y1


Abell2744_Y1NASA’s Spitzer and Hubble Space Telescopes have spotted what may be one of the most distant galaxies known, from when the universe was only about 650 million years old (the Big Bang was around 13.8 billion years ago). The galaxy, known as Abell2744 Y1, was about 3 percent the size our Milky Way galaxy and was producing about 10 times more stars, as wass typical for galaxies in the young universe.

Image Credit: NASA

Beam Me Up


hh24This image was taken by the Hubble Space Telescope in infrared light. The bright lines in this picture are particle beams, powerful jets of electrons and protons moving hundreds of km/s. Frequently, when a star forms, a disk of dust and gas circles the Young Stellar Object causes powerful central jets to appear. In this case, the energetic jets are creating aYSO called Herbig-Haro object 24 (HH 24), as they slam into the surrounding interstellar gas. The star forming region shown here lies about 1,500 light years away in the Orion B molecular cloud complex. Because of their rarity, jets like the one forming HH 24 are estimated to last only a few thousand years.

Image Credit: NASA

Seeing Double


Double QuasarTwo objects are clearly visible in this Hubble image, shining brightly side-by-side. When they were first discovered in 1979, the objects were thought to be separate objects, but astronomers soon realized that these twins are too identical! They are close together, lie at the same distance from us, and have surprisingly similar properties. The reason they are so similar is not some bizarre coincidence. They are in fact the same object. They are a double quasar known as QSO 0957+561 (aka  the Twin Quasar). It is among the oldest object we can see,  just under 14 billion light-years from Earth. Quasars are the intensely powerful centers of distant galaxies.

So, do we see this quasar twice?

Directly in our line of sight about 4 billion light-years from Earth is the huge galaxy YGKOW G1. This galaxy is gravitational lens, an object with a mass so great that it can bend the light from objects lying behind it. This phenomenon not only allows us to see objects that would otherwise be too remote, but also, in some instances, it allows us to see them twice. Along with the cluster of galaxies in which it resides, YGKOW G1 exerts an enormous gravitational force which affects the very space it sits in, warping and bending the environment and producing bizarre effects, such as this quasar double image.

Gravitational lensing is evidence for Einstein’s theory of general relativity. This theory had identified gravitational lensing as one of its observable effects, but until the discovery of these quasar “twins,” no such lensing had been observed since the idea was proposed in 1936.

Image Credit: NASA

A Really Big Black Hole


ExtremeBlackHoleAstronomers have used the Chandra X-ray Observatory and a group of other telescopes to reveal one of the most powerful black holes known. It has created enormous structures in the hot gas surrounding it and has prevented trillions of stars from forming.

The black hole is in a galaxy cluster named RX J1532.9+3021 (RX J1532 for short) about 3.9 billion light years from Earth. This image is a composite of X-ray data from Chandra revealing hot gas in the cluster in purple and visible data from the Hubble Space Telescope showing galaxies in yellow. The cluster is very bright in X-rays which indicates it is extremely massive, with a mass about a quadrillion—that’s a thousand trillion—times that of the Sun. At the center of the cluster is the large elliptical galaxy containing the supermassive black hole.

Image Credit: NASA

SBW1


SBW1This eye in space is known officially as [SBW2007] 1 but is nicknamed SBW1. It’s a nebula with a giant star at its center. The star was originally twenty times more massive than our Sun, and it is now encased in a swirling ring of purple gas, the remains its outer layers that were thrown off by violent pulsations and winds.

The star is probably destined to go supernova.

In 1987, we saw another star with striking similarities go supernova—SN 1987A. Early Hubble images of SN 1987A show similarities to SBW1. Both stars had identical debris rings of about the same size and age travelling at similar speeds; both were located in similar HII regions; and both were roughly the same brightness. SBW1 looks very much like a snapshot of SN1987A before it exploded.

SBW1 is more than 20 000 light-years  away, so it will be safe to watch if the supernova goes off. If we’re very lucky, it may happen in our own lifetimes.

Image Credit: NASA

Necklace Nebula


Necklace NebulaThis object, the Necklace Nebula, is a planetary nebula, the glowing remains of an ordinary, Sun-like star that have expanded to surround neighboring stars. The nebula consists of a bright ring almost 20 trillion km across, dotted with dense, bright knots of gas that resemble diamonds in a necklace. The knots glow brightly because of absorption of ultraviolet light from their central stars.

The Necklace Nebula is 15,000 light-years away in the constellation Sagitta (the Arrow). The composite image, taken by Hubble‘s Wide Field Camera 3, shows the glow of nitrogen (red), oxygen (green), and hydrogen (blue).

Image Credit: NASA

An Einstein Ring


Gravitational Lens 5921+0638An Einstein ring is a complete circle image of a background galaxy, which is formed when the background galaxy, a massive, foreground galaxy, and the observer are all aligned perfectly. One can be seen in this image of the gravitational lens 5921+0638 taken by the Hubble Space Telescope.

Gravitational lenses occur when light travelling towards us from a distant galaxy is magnified and distorted as it encounters a massive object between the galaxy and the observer. These gravitational lenses can effectively extend the range of a telescope, often allowing astronomers to peer much further back into the early Universe than they normally could.

Image Credit: NASA

International Crab


International CrabThe Crab nebula is the remnant of a supernova explosion recorded by Chinese astronomers in the year 1054. This is composite view of the Crab nebula was assembled using data from the Herschel Space Observatory and the Hubble Space Telescope. Herschel is a European Space Agency (ESA) mission with important NASA contributions, and Hubble is a NASA mission with important ESA contributions.

Hubble‘s view of the nebula at visible wavelengths used three different filters sensitive to the emission from oxygen and sulphur ions and is shown here in blue. Herschel’s far-infrared image reveals the emission from dust in the nebula and is shown here in red.

Image Credit: ESA/NASA

Our Densest Galactic Neighbor


Video Credit: NASA

M15


m15_hubble_960M15 (in the constellation of Pegasus) is an easy target for backyard astronomers. On a clear night, it’s visible as fuzzy spot with a decent pair of binoculars. A 150-mm or larger telescope will reveal some individual stars in the cluster. Here’s what it looks like using Hubble.

The cluster is estimated to be one of the oldest known, about 12 billion years old. It contains over 100 variable stars, eight known pulsars, and a double neutron star. Its central region has undergone core collapse and may contain a black hole.

Image Credit: NASA

A Cosmic Black Eye


M64_Black_Eye_GalaxyThe collision of two galaxies has resulted in this, M64 (aka The Black Eye Galaxy). To the casual observer M64 looks fairly normal, except for the huge band of dust blocking part of our view of the nucleus. All its star orbit the galactic center in the same direction, clockwise in this image from Hubble, but recent observations show that the interstellar gas in the outer regions of M64 rotates in the opposite direction from the gas and stars in the inner regions. This is believed to trigger the creation of many new stars around the boundary between the regions where the oppositely rotating gases collide.

The small satellite galaxy that merged with its larger neighbour has now been almost completely destroyed. Its stars have either entered the main galaxy or scattered into intergalactic space, but signs of the collision persist in the retrograde motion of gas at the outer edge of M64.

Image Credit: NASA