Nasa Image of the Day

Nebula RCW49

One of the most prolific birthing grounds in our Milky Way galaxy, a nebula called RCW 49, is exposed in superb detail for the first time in this new image from NASA's Spitzer Space Telescope. Located 13,700 light-years away in the southern constellation Centaurus, RCW 49 is a dark and dusty stellar nursery that houses more than 2,200 stars.

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Wonders of the Solar System Wonders of the Solar System has teamed up with to bring you the finest selection of astronomy related books at the best prices.

Browse through our bookstore and check out our fine selection of books from star charts and astrophotography to mathematical astronomy. We are sure you will find the book that best suits your needs.

Sky View Cafe
Sky View Cafe

Sky View Café is a Java applet that lets you use your web browser to see many types of astronomical information, in both graphical and numerical form. You can see which stars and planets will be out tonight in the sky above your home town, see how the next solar or lunar eclipse will look from London, or find out when the Moon rose over Sydney on your birthday ten years ago. Sky View Café includes star charts, a 3-D orrery, displays of the moons of Jupiter and Saturn, an astronomical event calendar, an ephemeris generator, and many other features. Enter Sky View Café now!

Buy A Star Gift - Name a star for any occasion, view it live on Google Sky
Universal Star Registry Certificate Star Naming Service
Name a star for yourself or for that special person as the perfect gift that will sparkle for a lifetime! Ideal for any occassion, birthdays, christenings, anniversaries and memorials. Reserve a place in the heavens for your loved ones

The Sky Tonight Astronomy News
A Weakened Black Hole Allows Its Galaxy To Awaken
Mon, 18 Nov 2019 13:00:00 ESTHubble Image

Supermassive black holes, weighing millions or even billions of times our Sun's mass, are still only a tiny fraction of the mass of the galaxies they inhabit. But in some cases, the central black hole is the tail wagging the dog. It seems that black holes can run hot or cold when it comes to either enhancing or squelching star birth inside a cluster of galaxies.

Typically, giant black holes, pumping out energy via jets, keep interstellar gas too warm to condense and form stars. Now, astronomers have found a cluster of galaxies, called the Phoenix cluster, where stars are forming at a furious rate because of the black hole's influence. This stellar turboboost is apparently linked to less energetic jets from a central black hole that do not pump up the gas temperature. Instead, the gas loses energy as it glows in X-rays. The gas cools to where it can form large numbers of stars at a breathtaking rate. Where our Milky Way forms one star per year on average, newborn stars are popping out of this cool gas at a rate of about 500 solar masses per year in the Phoenix cluster.

Unraveling this mystery required the combined power of NASA's Hubble Space Telescope, NASA's Chandra X-ray Observatory, and the Very Large Array (VLA) radio observatory near Socorro, New Mexico.

The VLA radio data reveals jets blasting out from the vicinity of the central black hole. These jets inflated bubbles in the hot gas that are detected in X-rays by Chandra. Hubble resolves bright blue filaments of newborn stars in cavities between the hot jet and gas clouds. As the black hole has grown more massive and more powerful, its influence has been increasing.

The foreshock in Earth’s magnetic environment - Read more >
Mon, 18 Nov 2019 16:00:00 +0100

The foreshock in Earth’s magnetic environment Image:

In this image, Earth is the dot to the left of the image and the large arc around it is our planet’s magnetic bow shock. The swirling pattern to the right is the foreshock region where the solar wind breaks into waves as it encounters reflected particles from the bow shock. The image was created using the Vlasiator model, a computer simulation developed at the University of Helsinki to study Earth’s magnetic interaction with the solar wind.

Earth’s magnetic song recorded for the first time during a solar storm - Read more >
Mon, 18 Nov 2019 16:00:00 +0100

The foreshock in Earth’s magnetic environment

Data from ESA’s Cluster mission has provided a recording of the eerie ‘song’ that Earth sings when it is hit by a solar storm.

Orion A in infrared - Read more >
Mon, 18 Nov 2019 09:00:00 +0100

Orion A in infrared Image:

Stars form within giant clouds of gas and dust that pervade galaxies like our own Milky Way. This image depicts one such cloud, known as Orion A, as seen by ESA’s Herschel and Planck space observatories.

At 1350 light years away, Orion A is the nearest heavyweight stellar nursery to us. The cloud is packed full of gas – it contains so much material, in fact, that it would be capable of producing tens of thousands of Suns. Along with its sibling, Orion B, the cloud makes up the Orion Molecular Cloud Complex, a vast star-forming region within the constella-tion of Orion, which is most prominent in the night sky during northern hemisphere winter and southern hemisphere summer.

The different colours visible here indicate the light emitted by interstellar dust grains mixed within the gas, as observed by Herschel at far-infrared and sub-millimetre wavelengths, while the texture of faint grey bands stretching across the frame, based on Planck’s measurements of the direction of the polarised light emitted by the dust, show the orientation of the magnetic field.

As evident from images like this, the space that sits between stars is not empty but is instead filled with a cool substance known as the interstellar medium (ISM) – a mix of gas and dust that often clumps together. When these clumps become dense enough they start to collapse under their own gravity and become hotter and hotter and denser and denser until they spark something exciting: the creation of new stars.

Magnetism is an important component of the ISM. Magnetic fields permeate the Universe, and are involved in helping clouds of matter maintain the delicate balance between pressure and gravity that eventually lead to the birth of stars. The mechanisms that oppose the gravitational collapse of star-forming clouds remain somewhat unclear, but a recent study suggests that interstellar magnetic fields play a significant role in guiding the flows of matter in the ISM, and may be a key player in preventing inter-stellar cloud collapse.

The study finds that matter within the ISM is coupled to the surrounding magnetic field and can only move along its lines, creating a sort of ‘conveyor belts’ of field-aligned matter, as expected from the effect of electromagnetic forces. When these interact with an external source of energy – such as an exploding star, or other material moving through the galaxy – these flows along the magnetic field lines converge. The process creates a compressed pocket of higher density that appears to be perpendicular to the field itself. As more and more matter streams inwards, this region becomes increasingly dense, until it eventually reaches the critical density for gravitational collapse and crumples in on itself, leading to the formation of stars.

The data comprising this image were gathered during Planck’s all-sky observations and Herschel’s ‘Gould Belt Survey’. Operational until 2013, both Herschel and Planck were instrumental in exploring the cool and the distant Universe, shedding light on many cosmic phenomena, from the formation of stars in our Milky Way galaxy to the expansion history of the entire Universe.

The study was published in Astronomy & Astrophysics (2019) by J. D. Soler, Max Planck Institute for Astronomy (Heidelberg, Germany).

Key methane measurements at Mars - Read more >
Wed, 13 Nov 2019 11:00:00 +0100

Key methane measurements at Mars Image:

This graphic summarises significant measurement attempts of methane at Mars. Reports of methane have been made by Earth-based telescopes, ESA’s Mars Express from orbit around Mars, and NASA’s Curiosity located on the surface at Gale Crater; they have also reported measurement attempts with no or very little methane detected. More recently, the ESA-Roscosmos ExoMars Trace Gas Orbiter reported an absence of methane, and provided a very low upper limit.
In order to reconcile the range of results, which show variations in both time and location, scientists have to understand better the different processes acting to create and destroy methane.

Proba-2 watches Mercury transit - Read more >
Tue, 12 Nov 2019 17:00:00 +0100

Video: 00:00:27

ESA's Proba-2 had a ring-side seat for the transit of Mercury on 11 November 2019. Proba-2 monitors the Sun from Earth orbit and was able to spot Mercury’s transit as a small black disc – seen here moving from left to right across the face of the Sun.

The images in this movie were taken with the satellite's extreme ultraviolet telescope.

Solar transits – where a celestial body is seen to pass across the solar disc from the perspective of Earth – are relatively rare events. Mercury undergoes around 13 transits a century; the last occurred in 2016 but the next is not until 2032. Both Mercury and the Sun are destinations for ESA missions: BepiColombo will arrive at Mercury in 2025, while Solar Orbiter is getting ready for a 2020 launch to study the Sun up close. Transits are also important outside of our Solar System, in the quest to find exoplanets. For example, a transiting planet causes a dip in brightness of its host star, revealing the presence of an exoplanet. Space missions like ESA’s Cheops will study known transiting exoplanets to determine more about their characteristics.

Proba-2 watches Mercury transit - Read more >
Tue, 12 Nov 2019 09:29:00 +0100

Proba-2 watches Mercury transit Image:

ESA's Proba-2 had a ring-side seat for the transit of Mercury on 11 November 2019.

Proba-2 monitors the Sun from Earth orbit and was able to spot Mercury’s transit as a small black disc – seen here to the right of centre as it passed across the face of the Sun. The image was taken with the SWAP extreme ultraviolet telescope.

Solar transits – where a celestial body is seen to pass across the solar disc from the perspective of Earth – are relatively rare events. Mercury undergoes around 13 transits a century, and will not occur again until 2032.

Proba-2 watches Mercury transit - Read more >
Tue, 12 Nov 2019 09:12:00 +0100

Proba-2 watches Mercury transit Image:

ESA's Proba-2 had a ring-side seat for the transit of Mercury on 11 November 2019.

Proba-2 monitors the Sun from Earth orbit and was able to spot Mercury’s transit as a small black disc – seen here at the far left as it begins its journey across the face of the Sun. The image was taken with the SWAP extreme ultraviolet telescope.

Solar transits – where a celestial body is seen to pass across the solar disc from the perspective of Earth – are relatively rare events. Mercury undergoes around 13 transits a century, and will not occur again until 2032.

Rosetta's ongoing science - Read more >
Tue, 12 Nov 2019 08:00:00 +0100

Video: 00:04:38

On 12 November 2014 Philae became the first spacecraft to land on a comet as part of the successful Rosetta mission to study Comet 67P/Churyumov-Gerasimenko. Five years later, and after the mission’s official end in 2016, Rosetta is continuing to provide insights into the origins of our Solar System.

Rosetta’s instruments have already discovered that the comet contained oxygen, organic molecules, noble gases and ’heavy’ or deuterated water different to that found on Earth.  
As scientists continue to analyse data from Rosetta’s instruments, including the ionised gas or plasma, the results are improving our understanding of comets. Mission data is also being delivered to an archive as a future resource.

Rosetta orbits the Sun every 6.5 years and will pass the Earth again, visible from ground-based telescopes, in 2021. ESA’s future Comet Interceptor mission will build on Rosetta’s success when it performs a flyby of a comet. But, unlike Rosetta, the comet will be new to our Solar System.

The film contains interviews with Charlotte Goetz, Research Fellow, ESA; Kathrin Altwegg, ROSINA instrument principal investigator, Rosetta/University of Bern; Colin Snodgrass, Comet Interceptor deputy principal investigator/University of Edinburgh

NASA's Hubble Captures a Dozen Galaxy Doppelgangers
Thu, 07 Nov 2019 14:00:00 ESTHubble Image

The “funhouse mirror” has delighted carnival-goers for more than a century by twisting peoples’ images into wildly distorted shapes. Its prolific inventor, Charles Frances Ritchel, called it the "Ritchel's Laugh-O-Graphs.” However, there was nothing funny – but instead practical – about warped images as far as Albert Einstein was concerned. In developing his general theory of relativity, Einstein imagined the universe as a grand funhouse mirror caused by wrinkles in the very fabric of space.

This recent picture from Hubble shows a galaxy nicknamed the "Sunburst Arc" that has been split into a kaleidoscope illusion of no fewer than 12 images formed by a massive foreground cluster of galaxies 4.6 billion light-years away.

This beautifully demonstrates Einstein's prediction that gravity from massive objects in space should bend light in a manner analogous to a funhouse mirror. His idea of space warping was at last proven in 1919 by observations of a solar eclipse where the sun’s bending of space could be measured. A further prediction was that the warping would create a so-called “gravitational lens” that, besides distortion, would increase the apparent size and brightness of distant background objects.

It wasn’t until 1979 that the first such gravitational lens was confirmed. An otherwise obscure galaxy split and amplified the light of a distant quasar located far behind it into a pair of images. Far more than a space-carnival novelty, gravitational lensing observations today are commonly used to find planets around other stars, zoom in on very distant galaxies, and map the distribution of otherwise invisible “dark matter” in the universe.

Building Solar Orbiter - Read more >
Thu, 31 Oct 2019 16:00:00 +0100

Video: 00:02:49

This timelapse shows some of the activities that took place during the integration of ESA's Solar Orbiter in the Hercules cleanroom at Airbus Defence and Space, Stevenage, UK.

Solar Orbiter is an ESA mission with strong NASA participation. The prime contractor is Airbus Defence and Space in Stevenage, UK. Solar Orbiter will launch on a NASA-provided Atlas V 411 in February 2020.

The mission will provide new perspectives on our star, including the first images of the Sun’s polar regions. Its complementary suite of instruments means it will be able to study the plasma environment locally around the spacecraft, and collect data from the Sun from afar, connecting the dots between the Sun’s activity, and the space environment in the inner Solar System.

Hubble Captures Galaxies' Ghostly Gaze
Mon, 28 Oct 2019 10:00:00 EDTHubble Image

The universe is a bubbling cauldron of matter and energy that have mixed together over billions of years to create a witches' brew of birth and destruction.

Firestorms of star birth sweeping across the heavens. Dying stars rattling the very fabric of space in titanic explosions. Death Star-like beams of energy blasting out of overfed black holes at nearly the speed of light. Large galaxies devouring smaller companions, like cosmic Pac-Men. Colossal collisions between galaxies flinging stars around like breaking pool balls. Hubble has seen them all.

This compulsive mayhem in space can produce weird-looking shapes that resemble creepy creatures seemingly conjured up in stories of the paranormal. Among them is the object in this new Hubble image.

The snapshot reveals what looks like an uncanny pair of glowing eyes glaring menacingly in our direction. The piercing "eyes" are the most prominent feature of what resembles the face of an otherworldly creature. This frightening object is actually the result of a titanic head-on collision between two galaxies.

Each "eye" is the bright core of a galaxy, the result of one galaxy slamming into another. The outline of the face is a ring of young blue stars. Other clumps of new stars form a nose and mouth.

The system is catalogued as Arp-Madore 2026-424, from the Arp-Madore "Catalogue of Southern Peculiar Galaxies and Associations."

Although galaxy collisions are common—especially back in the young universe—most of them are not head-on smashups, like the collision that likely created this Arp-Madore system. The violent encounter gives the system an arresting "ring" structure for only a short amount of time, about 100 million years. The two galaxies will merge completely in about 1 to 2 billion years, hiding their messy past.

Gaia astronomical revolution - Read more >
Tue, 22 Oct 2019 10:00:00 +0200

Video: 00:03:00

Launched in December 2013, the Gaia mission is revolutionising our understanding of the Milky Way. The space telescope is mapping our galaxy in unprecedented detail – measuring the position, movement and distance of stars.

At a meeting in Groningen in the Netherlands, scientists have been discussing the challenge of processing and visualising Gaia data.

Latest science results from the mission, also discussed in this A and B-roll, include a new understanding of how stars cluster together and the fact that today’s Milky Way was formed from a merger of galaxies.

More details on these science results:
Gaia untangles the starry strings of the Milky Way
Gaia uncovers major event in the formation of the Milky Way

Solar Orbiter ready to depart Europe - Read more >
Fri, 18 Oct 2019 15:00:00 +0200

Solar Orbiter at IABG

ESA’s Solar Orbiter mission has completed its test campaign in Europe and is now being packed ready for its journey to Cape Canaveral at the end of this month, ahead of launch in February 2020.

Solar Orbiter's journey around the Sun - Read more >
Thu, 17 Oct 2019 18:00:00 +0200

Video: 00:02:15

Animation showing the trajectory of Solar Orbiter around the Sun, highlighting the gravity assist manoeuvres that will enable the spacecraft to change inclination to observe the Sun from different perspectives.

During the initial cruise phase, which lasts until November 2021, Solar Orbiter will perform two gravity-assist manoeuvres around Venus and one around Earth to alter the spacecraft’s trajectory, guiding it towards the innermost regions of the Solar System. At the same time, Solar Orbiter will acquire in situ data and characterise and calibrate its remote-sensing instruments. The first close solar pass will take place in 2022 at around a third of Earth’s distance from the Sun.

The spacecraft’s orbit has been chosen to be ‘in resonance’ with Venus, which means that it will return to the planet’s vicinity every few orbits and can again use the planet’s gravity to alter or tilt its orbit. Initially Solar Orbiter will be confined to the same plane as the planets, but each encounter of Venus will increase its orbital inclination. For example, after the 2025 Venus encounter it will make its first solar pass at 17º inclination, increasing to 33º during a proposed mission extension phase, bringing even more of the polar regions into direct view.

Super Spirals Spin Super Fast
Thu, 17 Oct 2019 10:00:00 EDTHubble Image

You’ve probably never noticed it, but our solar system is moving along at quite a clip. Stars in the outer reaches of the Milky Way, including our Sun, orbit at an average speed of 130 miles per second. But that’s nothing compared to the most massive spiral galaxies. “Super spirals,” which are larger, brighter, and more massive than the Milky Way, spin even faster than expected for their mass, at speeds up to 350 miles per second.

Their rapid spin is a result of sitting within an extraordinarily massive cloud, or halo, of dark matter – invisible matter detectable only through its gravity. The largest “super spiral” studied here resides in a dark matter halo weighing at least 40 trillion times the mass of our Sun. The existence of super spirals provides more evidence that an alternative theory of gravity known as Modified Newtonian Dynamics, or MOND, is incorrect.

Hubble Observes First Confirmed Interstellar Comet
Wed, 16 Oct 2019 10:00:00 EDTHubble Image

No one knows where it came from. No one knows how long it has been drifting through the empty, cold abyss of interstellar space. But this year an object called comet 2I/Borisov came in from the cold. It was detected falling past our Sun by a Crimean amateur astronomer. This emissary from the black unknown captured the attention of worldwide astronomers who aimed all kinds of telescopes at it to watch the comet sprout a dust tail. The far visitor is only the second known object to enter our solar system coming from elsewhere in the galaxy, based on its speed and trajectory. Like a racetrack photographer trying to capture a speeding derby horse, Hubble took a series of snapshots as the comet streaked along at 110,000 miles per hour. Hubble provided the sharpest image to date of the fleeting comet, revealing a central concentration of dust around an unseen nucleus. The comet was 260 million miles from Earth when Hubble took the photo.

In 2017, the first identified interstellar visitor, an object formally named 'Oumuamua, swung within 24 million miles of the Sun before racing out of the solar system. Unlike comet 2I/Borisov, 'Oumuamua still defies any simple categorization. It did not behave like a comet, and it has a variety of unusual characteristics. Comet 2I/Borisov looks a lot like the traditional comets found inside our solar system, which sublimate ices, and cast off dust as they are warmed by the Sun. The wandering comet provides invaluable clues to the chemical composition, structure, and dust characteristics of planetary building blocks presumably forged in an alien star system.

Milky Way Raids Intergalactic 'Bank Accounts,' Hubble Study Finds
Thu, 10 Oct 2019 10:00:00 EDTHubble Image

Astronomers have discovered an unexplained surplus of gas flowing into our Milky Way after conducting a galaxy-wide audit of outflowing and inflowing gas. Rather than a gas equilibrium and "balanced books," 10 years of data from NASA's Hubble Space Telescope show there is more gas coming in than going out.

It is no secret that the Milky Way is frugal with its gas. The valuable raw material is recycled over billions of years—thrown out into the galactic halo via supernovas and violent stellar winds, and then used to form new generations of stars once it falls back to the galactic plane. The surplus of inflowing gas, however, was a surprise.

Hubble distinguished between outflowing and inflowing clouds using its sensitive Cosmic Origins Spectrograph (COS), which detects the movement of the invisible gas. As the gas moves away it appears redder, while gas falling back toward the Milky Way is bluer.

The source of the excess gas inflow remains a mystery. Astronomers theorize that the gas could be coming from the intergalactic medium, as well as the Milky Way raiding the gas "bank accounts" of its small satellite galaxies using its considerably greater gravitational pull.

River relic spied by Mars Express - Read more >
Thu, 10 Oct 2019 11:00:00 +0200

Plan view of Nirgal Vallis

Mars may seem to be an alien world, but many of its features look eerily familiar – such as this ancient, dried-up river system that stretches out for nearly 700 kilometres across the surface, making it one of the longest valley networks on the planet.

Exoplanet and cosmology discoveries awarded Nobel Prize in Physics - Read more >
Tue, 08 Oct 2019 18:00:00 +0200

Exoplanet imaginarium

ESA congratulates 2019 Nobel Prize in Physics laureates Michel Mayor and Didier Queloz, who have been awarded the prestigious prize for the first discovery of an exoplanet orbiting a solar-type star, and James Peebles, honoured for the theoretical framework of cosmology used to investigate the Universe on its largest scales.

Call for Media: Last chance to view Europe’s Solar Orbiter - Read more >
Thu, 03 Oct 2019 14:00:00 +0200

Solar Orbiter

ESA’s new Sun explorer will leave Europe soon, with final launch preparations starting in November at Cape Canaveral in Florida, US. ESA and Airbus Defence and Space invite members of the media to get a final glimpse of Solar Orbiter on 18 October at IABG’s space test centre in Ottobrunn, near Munich, Germany, before the spacecraft departs for the launch site.

NASA's Hubble Finds Water Vapor on Habitable-Zone Exoplanet for the First Time
Fri, 13 Sep 2019 11:00:00 EDTHubble Image

To date, approximately 4,000 planets have been found orbiting other stars. The majority are extremely hostile to any chances for life: with exotic atmospheres, wide temperature extremes, and oddball orbits. Astronomers have now made an important step toward the ultimate goal of finding an exoplanet with an atmosphere more like Earth's, and having moderate temperatures. Water vapor has been identified in the atmosphere of a planet called K2-18b, located 110 light-years away. And, where there's water there could be clouds and rain. The planet is also at the right distance from its star to have a temperate climate where the water doesn't evaporate or freeze. But don't go looking for real estate yet. The planet is in a category not found in our solar system. It is larger than Earth but smaller than Neptune. It might have a rocky surface, but it is more likely a giant ball of liquid and gas, like Neptune. Hundreds of known exoplanets fall into this mass range. So, it's important for astronomers to characterize the worlds and assess the chances for supporting life as we know it.

Saturn's Rings Shine in New Hubble Portrait
Thu, 12 Sep 2019 10:00:00 EDTHubble Image

Saturn is so beautiful that astronomers cannot resist using the Hubble Space Telescope to take yearly snapshots of the ringed world when it is near its closest distance to Earth.

These images, however, are more than just beauty shots. They reveal a planet with a turbulent, dynamic atmosphere. This year's Hubble offering, for example, shows that a large storm visible in the 2018 Hubble image in the north polar region has vanished. Smaller storms pop into view like popcorn kernels popping in a microwave oven before disappearing just as quickly. Even the planet's banded structure reveals subtle changes in color.

But the latest image shows plenty that hasn't changed. The mysterious six-sided pattern, called the "hexagon," still exists on the north pole. Caused by a high-speed jet stream, the hexagon was first discovered in 1981 by NASA's Voyager 1 spacecraft.

Saturn's signature rings are still as stunning as ever. The image reveals that the ring system is tilted toward Earth, giving viewers a magnificent look at the bright, icy structure. Hubble resolves numerous ringlets and the fainter inner rings.

This image reveals an unprecedented clarity only seen previously in snapshots taken by NASA spacecraft visiting the distant planet. Astronomers will continue their yearly monitoring of the planet to track shifting weather patterns and identify other changes. The second in the yearly series, this image is part of the Outer Planets Atmospheres Legacy (OPAL) project. OPAL is helping scientists understand the atmospheric dynamics and evolution of our solar system's gas giant planets.

Hubble Explores the Formation and Evolution of Star Clusters in the Large Magellanic Cloud
Mon, 09 Sep 2019 11:00:00 EDTHubble Image

Like batches of cookies, stars are born together in groups. These star clusters, containing as many as 1 million members, evolve over time largely through a gravitational pinball where more massive stars are segregated from lower mass stars. Heavy stars tend to progressively sink toward the central region of the star cluster, while low-mass stars can escape from the system.

For the first time, the Hubble Space Telescope has been used to measure the effects of this dynamical aging on star clusters. They are all located 160,000 light-years from Earth in a satellite galaxy, the Large Magellanic Cloud (LMC). The diminutive galaxy is an ideal target because it hosts a selection of easily observed star clusters covering a wide range of ages.

Francesco Ferraro of the University of Bologna in Italy and his team used Hubble to observe five aging LMC star clusters — all born at about the same time but with different sizes — and succeeded in ranking them in terms of the level of dynamical evolution, which affects their shape.

Hubble's New Portrait of Jupiter
Thu, 08 Aug 2019 10:00:00 EDTHubble Image

Jupiter is the king of the solar system, more massive than all of the other solar-system planets combined. Although astronomers have been observing the gas-giant planet for hundreds of years, it still remains a mysterious world.

Astronomers don't have definitive answers, for example, of why cloud bands and storms change colors, or why storms shrink in size. The most prominent long-lasting feature, the Great Red Spot, has been downsizing since the 1800s. However, the giant storm is still large enough to swallow Earth.

The Red Spot is anchored in a roiling atmosphere that is powered by heat welling up from the monster planet's deep interior, which drives a turbulent atmosphere. In contrast, sunlight powers Earth's atmosphere. From Jupiter, however, the Sun is much fainter because the planet is much farther away from it. Jupiter's upper atmosphere is a riot of colorful clouds, contained in bands that whisk along at different wind speeds and in alternating directions. Dynamic features such as cyclones and anticyclones (high-pressure storms that rotate counterclockwise in the southern hemisphere) abound.

Attempting to understand the forces driving Jupiter's atmosphere is like trying to predict the pattern cream will make when it is poured into a hot cup of coffee. Researchers are hoping that Hubble's yearly monitoring of the planet—as an interplanetary weatherman—will reveal the shifting behavior of Jupiter's clouds. Hubble images should help unravel many of the planet's outstanding puzzles. This new Hubble image is part of that yearly study, called the Outer Planets Atmospheres Legacy program, or OPAL.

Hubble Uncovers a 'Heavy Metal' Exoplanet Shaped Like a Football
Thu, 01 Aug 2019 10:00:00 EDTHubble Image

The scorching hot exoplanet WASP-121b represents a new twist on the phrase "heavy metal."

There are no loud electric guitar riffs, characteristic of heavy metal music, streaming into space. What is escaping the planet is iron and magnesium gas, dubbed heavy metals, because they are heavier than lightweight hydrogen and helium. The observations by the Hubble Space Telescope represent the first time heavy metal gas has been detected floating away from an exoplanet.

A scorching planet, WASP-121b orbits precariously close to a star that is even hotter than our Sun. The intense radiation heats the planet's upper atmosphere to a blazing 4,600 degrees Fahrenheit. Apparently, the lower atmosphere is still so hot that iron and magnesium remain in gaseous form and stream to the upper atmosphere, where they escape into space on the coattails of hydrogen and helium gas.

The sizzling planet is also so close to its star that it is on the cusp of being ripped apart by the star's intense pull. This hugging distance means that the planet is stretched into a football shape due to gravitational tidal forces.

New Hubble Constant Measurement Adds to Mystery of Universe's Expansion Rate
Tue, 16 Jul 2019 08:00:00 EDTHubble Image

In 1924, American astronomer Edwin Hubble announced that he discovered galaxies outside of our Milky Way by using the powerful new Hooker telescope perched above Los Angeles. By measuring the distances to these galaxies, he realized the farther away a galaxy is, the faster it appears to be receding from us. This was incontrovertible evidence the universe is uniformly expanding in all directions. For nearly a decade Albert Einstein refused to accept the observational evidence. His theory of general relativity described a static universe. But this could only be accomplished by invoking a "cosmological constant," which he described as repulsive property of space that would counterbalance the pull of gravity and prevent the universe from imploding. The expansion rate is the basis of the Hubble constant. It is a sought-after value because it yields clues to the origin, age, evolution, and future fate of our universe.

For nearly the past century astronomers have worked meticulously to precisely measure the Hubble constant. Before the Hubble Space Telescope was launched in 1990, the universe's age was thought to lie between 10 and 20 billion years, based on different estimates of the Hubble constant. Improving this value was one of the biggest justifications for building the Hubble telescope. This paid off in the early 1990s when a team led by Wendy Freedman of the University of Chicago greatly refined the Hubble constant value to a precision of 10%. This was possible because the Hubble telescope is so sharp at finding and measuring Cepheid variable stars as milepost markers — just as Edwin Hubble did 70 years earlier.

But astronomers strive for ever greater precision, and this requires further refining yardsticks for measuring vast intergalactic distances of billions of light-years. Freedman's latest research looks at aging red giant stars in nearby galaxies. They are also milepost markers because they all reach the same peak brightness at a critical stage of their late evolution. This can be used to calculate distances.

Freedman's research is one of several recent studies that point to a nagging discrepancy between the universe's modern expansion rate and predictions based on the universe as it was more than 13 billion years ago, as measured by the European Space Agency's Planck satellite. This latest measurement offers new evidence suggesting that there may be something fundamentally flawed in the current model of the universe.

Hubble Uncovers Black Hole Disk that Shouldn't Exist
Thu, 11 Jul 2019 10:00:00 EDTHubble Image

Astronomers are always tickled when they find something they didn't expect to be there. Peering deep into the heart of the majestic spiral galaxy NGC 3147, researchers uncovered a swirling gas disk precariously close to a black hole weighing about 250 million times the mass of our Sun. The surprise is that they thought the black hole was so malnourished, it shouldn’t have such a structure around it. It's basically a "Mini-Me" version of more powerful disks seen in very active galaxies.

What's especially intriguing is that the disk is so deeply embedded in the black hole's intense gravitational field, its light is being stretched and intensified by the black hole's powerful grasp. It's a unique, real-world demonstration of Einstein's laws of relativity, formulated a century ago.

Hubble clocked material whirling around the black hole as moving at more than 10% of the speed of light. And, the gas astronomers measured is so entrenched in the gravitational well that light is struggling to climb out, and therefore appears stretched to redder wavelengths.

STScI to Design Science Operations for New Panoramic Space Telescope
Tue, 02 Jul 2019 17:00:00 EDTHubble Image

NASA has awarded a contract to the Space Telescope Science Institute (STScI) in Baltimore, Maryland, for the Science Operations Center (SOC) of the Wide Field Infrared Survey Telescope (WFIRST) mission. WFIRST is a NASA observatory designed to settle essential questions in a wide-range of science areas, including dark energy and dark matter, and planets outside our solar system.

Atmosphere of Mid-Size Planet Revealed by Hubble and Spitzer
Tue, 02 Jul 2019 11:00:00 EDTHubble Image

Our solar system contains two major classes of planets. Earth is a rocky terrestrial planet, as are Mercury, Venus, and Mars. At about the distance of the asteroid belt, there is a "frost line" where space is so cold more volatile material, like water, can remain frozen. Out here live the gas giants–Jupiter, Saturn, Uranus, and Neptune–which have bulked up on hydrogen and helium and other volatiles.

Astronomers are curious about a new class of planet not found in the Solar System. Weighing in at 12.6 Earth masses the planet is more massive than Earth, but less massive than Neptune (hence, intermediate between the rocky and gaseous planets in the Solar System). What's more, the planet, GJ 3470 b, is so close to its red dwarf star that it completes one orbit in just three days! As odd as it seems, planets in this mass range are likely the most abundant throughout the galaxy, based on surveys by NASA's Kepler space telescope. But they are not found in our own solar system.

Astronomers enlisted the combined multi-wavelength capabilities of NASA's Hubble and Spitzer space telescopes to assemble for the first time a "fingerprint" of the chemical composition of GJ 3470 b's atmosphere, which turns out to be mostly hydrogen and helium, and surprisingly, largely lacking heavier elements. One possible explanation is that the planet formed as a 10-Earth-mass rocky core that then accumulated hydrogen very close to its star, rather than migrated in which is the conventional wisdom for star-hugging planets.

Hubble Captures the Galaxy's Biggest Ongoing Stellar Fireworks Show
Mon, 01 Jul 2019 10:00:00 EDTHubble Image

In the mid-1800s, mariners sailing the southern seas navigated at night by a brilliant star in the constellation Carina. The star, named Eta Carinae, was the second brightest star in the sky for more than a decade. Those mariners could hardly have imagined that by the mid-1860s the brilliant orb would no longer be visible. Eta Carinae was enveloped by a cloud of dust ejected during a violent outburst.

Stars don't normally play vanishing acts unless they are undergoing rapid and violent activity. Observations by the Hubble Space Telescope and other observatories have helped astronomers piece together the story of this unique star's petulant behavior. During part of its adult life, Eta Carinae has undergone a series of eruptions, becoming extremely bright during each episode, before fading away. One explanation for the monster star's antics is that the convulsions were caused by a complex interplay of as many as three stars, all gravitationally bound in one system. The most massive member – weighing in at 150 times our Sun's mass – swallowed one of the stars. This violent event ignited the massive outburst of the mid-1800s. Evidence for that event, dubbed the Great Eruption, lies in the huge, expanding bipolar lobes of hot gas surrounding the system.

Because of Eta Carinae's violent history, astronomers have kept watch over its activities. Although Hubble has monitored the volatile superstar for 25 years, it still is uncovering new revelations. Using Hubble to map the ultraviolet-light glow of magnesium embedded in warm gas, astronomers were surprised to discover the gas in places they had not seen it before. The newly revealed gas is important for understanding how the eruption began, because it represents the fast and energetic ejection of material that may have been expelled by the star shortly before the expulsion of the bipolar bubbles.

One of the most massive known stars in the Milky Way galaxy, Eta Carinae is destined to finally meet its end by exploding as a supernova.

Table Salt Compound Spotted on Europa
Wed, 12 Jun 2019 15:00:00 EDTHubble Image

Finding common table salt — sodium chloride — on the surface of a moon is more than just a scientific curiosity when that moon is Europa, a potential abode of life.

If the salt came from the briny subsurface ocean of Europa, a satellite of Jupiter, that ocean may chemically resemble Earth's oceans more than previously thought. Because Europa's solid, icy crust is geologically young it has been suspected that whatever salts exist on the surface may come from the ocean below, which might host microorganisms.

Using visible-light spectral analysis, planetary scientists at Caltech and NASA's Jet Propulsion Laboratory discovered that the yellow color visible on portions of the surface of Europa is sodium chloride. They reached this conclusion with spectroscopic data from NASA's Hubble Space Telescope. Researchers were able to identify a distinct absorption in the visible spectrum which matches how salt would look when irradiated by the Sun.

Tara Regio is the yellowish area to left of center, in this NASA Galileo image of Europa’s surface. This region of geologic chaos is the area researchers identified an abundance of sodium chloride.

The finding was published in Science Advances on June 12.

A Pair of Fledgling Planets Directly Seen Growing Around a Young Star
Mon, 03 Jun 2019 11:00:00 EDTHubble Image

In order to grow to Jupiter size or larger, a gas giant planet must slurp large quantities of hydrogen and other gases from the disk in which it forms. Astronomers have looked for evidence of this process, but direct observations are challenging because planets become lost in the glare of their star. A team has succeeded in making ground-based observations of two planets accreting matter from a disk. It represents only the second multi-planet system to be directly imaged.

This Month's Sky Map
This Month's Sky Map

Take a look at this month's Sky Map to help you explore the wonders of the night sky!

Ideal for all sky watchers including beginners to astronomy.

The Sky Map will help you identify planets, bright stars, constellations and nebulae!
Printable version available too!

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