Astronomy Archives

August 12, 2010December 24, 2015 by Nancy Atkinson

Einstein@Home Citizen Scientists Discover Weird Pulsar

Screenshot of Einstein@Home. Image courtesty of B. Knispel of Albert Einstein Institute

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Hooray for citizen scientists! The Einstein@Home project has discovered a unusual pulsar approximately 17,000 light-years away in the constellation Vulpecula. The project works by people “donating” idle time on their home computers. This is the first deep-space discovery by Einstein@Home, and the finding is credited to Chris and Helen Colvin, from Ames, Iowa in the US, and Daniel Gebhardt of Universitat Mainz, Musikinformatik,Germany.

The newly discovered pulsar, PSR J2007+2722, is an isolated neutron star that rotates 41 times per second and has an unusually low magnetic field.

Jim Cordes, Cornell professor of astronomy, said the object is particularly interesting because it is likely a recycled pulsar: a neutron star that once had a companion star from which it acquired mass; but whose companion exploded, kicking it free.

Unlike most pulsars that spin as quickly and steadily, PSR J2007+2722 sits alone in space, and has no orbiting companion star. However, the scientists say they can not rule out that it may be a young pulsar born with an lower-than-usual magnetic field.

“We think there should be more of these disrupted binary pulsars, but there haven’t been that many found,” said Cordes. “No matter what else we find out about it, this pulsar is bound to be extremely interesting for understanding the basic physics of neutron stars and how they form.”

The discovery demonstrates the power of the network used to collect and sort through vast amounts of data, Cordes said.

Einstein@Home was originally organized to find gravitational waves — ripples in space-time — using the Laser Interferometer Gravitational Wave Observatory (LIGO). In 2009, data from the Arecibo Observatory were included in the processing.

Chris and Helen Colvin who were credited with discovering a new pulsar. Image courtesy Chris Colvin.

Einstein@Home is based at the Center for Gravitation and Cosmology at the University of Wisconsin-Milwaukee and at the Max Planck Institute for Gravitational Physics (Albert Einstein Institute, or AEI) in
Hannover, Germany. About one-third of Einstein@Home’s computing capacity is used to search Arecibo data.

Einstein@Home volunteer Daniel Gebhardt from Germany. Image couresty of Gebhardt.

“This is a thrilling moment for Einstein@Home and our volunteers. It proves that public participation can discover new things in our universe,” said Bruce Allen, leader of the Einstein@Home project, AEI director and adjunct professor of physics at the University of Wisconsin-Milwaukee. “I hope it inspires more people to join us to help find other secrets hidden in the data.”

Gebhardt and the Colvins will receive plaques noting their discovery, and all plan to stay involved.

For information on how you can get involved in the project, see the Einstein@Home website.

Sources: Cornell University, ScienceExpress.

On a related note, check out these Albert Einstein quotes.

August 11, 2010December 24, 2015 by Nancy Atkinson

Ambitious Survey Spots Stellar Nurseries

VISTA Magellanic Cloud Survey view of the Tarantula Nebula. Credit: ESO/M.-R. Cioni/VISTA Magellanic Cloud survey. Acknowledgment: Cambridge Astronomical Survey Unit

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ESO’s VISTA telescope has begun a new survey of the Magellanic Cloud, and this spectacular image of the Tarantula Nebula is a taste of great things to come from this near-infrared scan of the more interesting galaxies in our neighborhood. This panoramic near-infrared view captures the nebula itself in great detail as well as the rich surrounding area of sky. “This view is of one of the most important regions of star formation in the local Universe — the spectacular 30 Doradus star-forming region, also called the Tarantula Nebula,” said the leader of the survey team, Maria-Rosa Cioni from the University of Hertfordshire. “At its core is a large cluster of stars called RMC 136, in which some of the most massive stars known are located.”

VISTA is a new survey telescope at the Paranal Observatory in Chile, and is equipped with a huge camera that detects light in the near-infrared part of the spectrum, revealing a wealth of detail about astronomical objects that gives us insight into the inner workings of astronomical phenomena. Near-infrared light has a longer wavelength than visible light, fortunately, it can pass through much of the dust that would normally obscure the views that our eyes can see. This makes it particularly useful for studying objects such as young stars that are still enshrouded in the gas and dust clouds from which they formed. Another powerful aspect of VISTA is the large area of the sky that its camera can capture in each shot.
The VISTA Magellanic Cloud Survey is one of six huge near-infrared surveys of the southern sky that will take up most of the first five years of operations of VISTA.

This project will scan a vast area — 184 square degrees of the sky (corresponding to almost one thousand times the apparent area of the full Moon) including our neighboring galaxies the Large and Small Magellanic Clouds. The end result will be a detailed study of the star formation history and three-dimensional geometry of the Magellanic system.

“The VISTA images will allow us to extend our studies beyond the inner regions of the Tarantula into the multitude of smaller stellar nurseries nearby, which also harbor a rich population of young and massive stars,” said Chris Evans who is part of the VMC team. “Armed with the new, exquisite infrared images, we will be able to probe the cocoons in which massive stars are still forming today, while also looking at their interaction with older stars in the wider region.”

The wide-field image shows a host of different objects. The bright area above the centre is the Tarantula Nebula itself, with the RMC 136 cluster of massive stars in its core. To the left is the NGC 2100 star cluster. To the right is the tiny remnant of the supernova SN1987A (eso1032). Below the centre are a series of star-forming regions including NGC 2080 — nicknamed the “Ghost Head Nebula” — and the NGC 2083 star cluster.

See more images, zoomable images, and movies of the Tarantula Nebula at the ESO website.

August 8, 2010December 24, 2015 by Tammy Plotner

2010 Perseid Meteor Shower

In just a few days – during the evening hours of August 12 and morning of August 13 – one of the year’s most reliable meteor showers is about to grace this year’s dark skies. Not only will we be in for some celestial fireworks, but the planets are going to put on a show as well. Who, what, when, where, why and how? Then step inside and let’s talk about the 2010 Perseid meteor shower…

During the latter half of July and the beginning of August, the Earth cruises through several minor cometary debris streams – producing equally minor meteor showers which meander through the constellations of Cygnus, Capricornus and Aquarius. This is the type of normal activity which is enjoyed by both the northern and southern hemisphere. One any given good, dark night, you might spot as many as a dozen meteors during an evening’s observing session. It’s a nice transition in the weather for both halves of Earth and this period of time makes for comfortable watching. While I love catching a sparkling trail when I really wasn’t expecting or waiting for one, there’s nothing in the heavens that can make me yell out loud like being witness to a productive meteor shower.

And the Perseids produce…

Where exactly did all the “stuff” come from that causes the annual Perseid meteor shower to be so reliable? Try periodic comet 109P/Swift-Tuttle. Discovered in 1862, Swift-Tuttle is called “periodic” because it makes a pass through our solar system about every 133-135 years leaving behind a debris trail. As early as 36 AD, Chinese astronomers began to notice a sharp peak of meteor activity during this time and began keeping record. Other astronomers followed suit until astronomy became a rather dangerous occupation and facts and figures began to dwindle. Although often referred to as “the tears of St. Lawrence” to celebrate the martyr’s death on August 10, it wasn’t until 1835 and Adolphe Quetelet that the annual Perseid was actually given credit to an individual for pinpointing its radiant and peak date.

Within four years, sharp-eyed observers had not only began to note the Perseid presence, but to make an accurate hourly account of the fall rate as well. In 1839, E. Heis gave us his first written documentation of a maximum rate of 160 per hour and over the next several decades, many other observers joined him. What they noticed through their observations was the fall rate changed from year to year… Why?

Between 1864 and 1866, Giovanni Schiaparelli also took an interest in the Perseids and computed the stream’s orbit. What he discovered was astounding. It nearly matched that of a comet discovered just two years earlier – 109P/Swift-Tuttle. After that, it didn’t take very long to figure out each high spike in fall rates also corresponded with the comet’s known perihelion. It was the very first time a meteor shower had been positively identified with a comet!

But, when it comes to science, proving a speculation is everything. Record keeping for that period of time wasn’t exactly the best and in 1973 astronomer Brian Marsden was busy trying to predict the return of comet Swift/Tuttle. His chosen date was 1981 and as annual activity of the Perseid meteor shower increased, so did the excitement of recapturing the comet. However, like so many astronomical predictions, the traveler from Oort Cloud failed to make its debut appearance Needless to say, between disappointment and lunar interference, interest in the Perseid’s cometary originator quickly faded. However, Marsden wasn’t about to give up. Choosing another documented comet seen in 1737, he made another prediction… Swift/Tuttle would return in 1992.

This time was sweet success.

With 18 years between now and comet Swift/Tuttle’s last perihelion, will the 2010 Perseid meteor activity be a smashing shower or a dwindling display? It’s really hard to say because the stream is so wide and complex. We know when the Earth passes through this outgassing of materials that we can expect a certain amount of activity during a marginal time period – but we can only make a guess at how much material was expelled. There may have been time centuries ago when the comet did something very unexpected (as comets have a way of doing) and left a dense cloud just waiting for us to orbit through… And it may be burning itself out during each successive pass around Sol. So many things can happen! Jupiter may have affected the stream’s position – or a huge flurry of activity might occur during daylight. But what about this year?

Thankfully there will be no Moon to obscure fainter meteors and zenith hourly rates may approach up to nearly 100 per hour. But that’s a very optimistic estimate since the Perseids are notoriously fast – burning through our atmosphere at 140,000 mph – and sometimes very faint. As the evening begins, facing east/northeast will be best for most northern hemisphere observers, and follow Perseus to the north as it rises. Unfortunately, southern hemisphere observers aren’t likely to see any of this activity – but it never hurts to keep watch to the northern horizon if you’re out. If you have to be selective about the times you watch, the very best views will be had when the constellation is at its highest – after local midnight through local dawn.

Don’t wait until the peak date to begin your observations. Perseid activity is already underway at 15 to 20 per hour and the fall rate will only continue to increase as it nears the night of August 12/13th when up to 75 meteors may grace the starry skies. If you live in a light polluted area, make plans to get rural. Many farmers and home owners in the countryside are more than happy to grant you permission to choose a safe observing spot on their land if you explain what you’re doing – so ask! Be sure to take along things which will aid in your comfort, such as a reclining lawn chair or blanket (meteor neck sucks). Make it a popcorn and soda family event! But stay away from white light. If being in the wild scares you a bit, create your own “night vision friendly” flashlight by stretching a red balloon over the lens. If you arrive at sunset? Then check out the beautiful conjunction of Mercury Mars, Saturn, Venus and the very tender crescent Moon….

Wishing you clear skies and the very best of luck!

Here’s information on the 2009 Perseids.

August 7, 2010December 24, 2015 by Steve Nerlich

Astronomy Without A Telescope – Strange Stars

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Atoms are made of protons, neutrons and electrons. If you cram them together and heat them up you get plasma where the electrons are only loosely associated with individual nuclei and you get a dynamic, light-emitting mix of positively charged ions and negatively charged electrons. If you cram that matter together even further, you drive electrons to merge with protons and you are left with a collection of neutrons – like in a neutron star. So, what if you keep cramming that collection of neutrons together into an even higher density? Well, eventually you get a black hole – but before that (at least hypothetically) you get a strange star.

The theory has it that compressing neutrons can eventually overcome the strong interaction, breaking down a neutron into its constituent quarks, giving a roughly equal mix of up, down and strange quarks – allowing these particles to be crammed even closer together in a smaller volume. By convention, this is called strange matter. It has been suggested that very massive neutron stars may have strange matter in their compressed cores.

However, some say that strange matter has a more fundamentally stable configuration than other matter. So, once a star’s core becomes strange, contact between it and baryonic (i.e. protons and neutrons) matter might drive the baryonic matter to adopt the strange (but more stable) matter configuration. This is the sort of thinking behind why the Large Hadron Collider might have destroyed the Earth by producing strangelets, which then produce a Kurt Vonnegut Ice-9 scenario. However, since the LHC hasn’t done any such thing, it’s reasonable to think that strange stars probably don’t form this way either.

More likely a ‘naked’ strange star, with strange matter extending from its core to its surface, might evolve naturally under its own self gravity. Once a neutron star’s core becomes strange matter, it should contract inwards leaving behind volume for an outer layer to be pulled inwards into a smaller radius and a higher density, at which point that outer layer might also become strange… and so on. Just as it seems implausible to have a star whose core is so dense that it’s essentially a black hole, but still with a star-like crust – so it may be that when a neutron star develops a strange core it inevitably becomes strange throughout.

Anyhow, if they exist at all, strange stars should have some tell tale characteristics. We know that neutron stars tend to lie in the range of 1.4 to 2 solar masses – and that any star with a neutron star’s density that’s over 10 solar masses has to become a black hole. That leaves a bit of a gap – although there is evidence of stellar black holes down to only 3 solar masses, so the gap for strange stars to form may only be in that 2 to 3 solar masses range.

By adopting a more compressed 'ground state' of matter, a strange (quark) star should be smaller, but more massive, than a neutron star. RXJ1856 is in the ballpark for size, but may not be massive enough to fit the theory. Credit: chandra.harvard.edu

The likely electrodynamic properties of strange stars are also of interest (see below). It is likely that electrons will be displaced towards the surface – leaving the body of the star with a nett positive charge surrounded by an atmosphere of negatively charged electrons. Presuming a degree of differential rotation between the star and its electron atmosphere, such a structure would generate a magnetic field of the magnitude that can be observed in a number of candidate stars.

Another distinct feature should be a size that is smaller than most neutron stars. One strange star candidate is RXJ1856, which appears to be a neutron star, but is only 11 km in diameter. Some astrophysicists may have muttered hmmm… that’s strange on hearing about it – but it remains to be confirmed that it really is.

Further reading: Negreiros et al (2010) Properties of Bare Strange Stars Associated with Surface Electrical Fields.

August 5, 2010January 20, 2016 by Nancy Atkinson

Stunning Aurora Videos

If you weren’t lucky enough to be in the right place or the right time to see any of the aurora produced by the Sun’s recent spate of activity, skywatchers around the world have started posting videos online of some really spectacular Northern Lights. Above, is the view on August 4, 2010 from Telemark, Norway. Below are more sights, also from August 4, from Latvia and Risør, Norway. These videos were posted on CitizenTube, a newsy version of YouTube.
Continue reading “Stunning Aurora Videos”

August 4, 2010December 24, 2015 by Nicholos Wethington

Telescope’s Laser Pointer Clarifies Blurry Skies

The new laser adaptive optics system in action. At Mount Hopkins in Arizona, a bundle of five lasers is shot into the atmosphere to improve the imaging of the 6.3-meter MMT telescope. Image Credit: Thomas Stalcup

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While it’s handy for us humans (and all of the other life on our planet for that matter), the atmosphere is almost universally cursed among astronomers. It’s great for breathing, but when it comes to astronomical observations of faint objects, all the atmosphere tends to do is muck up the view. In the past 20 years, development of adaptive optics – essentially telescopes that change the shape of their mirrors to improve their imaging capability – has dramatically improved what we can see in space from the Earth.

With a new technique involving lasers (Yes! Lasers!), the images capable with an adaptive optics telescope could be nearly as crisp as those from the Hubble Space Telescope over a wide field of view. A team of University of Arizona astronomers led by Michael Hart has developed a technique that helps calibrate the surface of the telescope very precisely, which leads to very, very clear images of objects that would normally be very blurry.

Laser adaptive optics in telescopes are a relatively new development in getting better image quality out of ground-based telescopes. While it’s nice to be able to use space-based telescopes like the Hubble and the forthcoming James Webb Space Telescope, they are certainly expensive to launch and maintain. On top of that, there are a lot of astronomers competing for very little time on these telescopes. Telescopes like the Very Large Telescope in Chile, and the Keck Telescope in Hawaii both already use laser adaptive optics to improve imaging.

Initially, adaptive optics focused in on a brighter star near the area of the sky that the telescope was observing, and actuators in the back of the mirror were moved very rapidly by a computer to cancel out atmospheric distortions. This system is limited, however, to areas of the sky that contain such an object.

Laser adaptive optics are more flexible in their usability – the technique involves using a single laser to excite molecules in the atmosphere to glow, and then using this as a “guide star” to calibrate the mirror to correct for distortions caused by turbulence in the atmosphere. A computer analyzes the incoming light from the artificial guide star, and can determine just how the atmosphere is behaving, changing the surface of the mirror to compensate.

In using a single laser, the adaptive optics can only compensate for turbulence in a very limited field of view. The new technique, pioneered at the 6.5-m MMT telescope in Arizona, uses not just one laser but five green lasers to produce five separate guide stars over a wider field of view, 2 arc minutes. The angular resolution is less than that of the single laser variety – for comparison, the Keck or VLT can produce images with a 30-60 milli-arcsecond resolution, but being able to see better over a wider field of view has many advantages.

Better, or worse? — In the image on the left, the cluster M3 appears blurry with the laser adaptive optics system turned off. Things are much clearer using the system, and individual stars in the cluster become visible, as can be seen in the image on the right. Image Credit: Michael Hart

The ability to take the spectra of older galaxies, which are very faint, is possible using this technique. By taking their spectra, scientists are better able to understand the composition and structure of objects in space. Using the new technique, taking the spectra of galaxies that are 10 billion years old – and thus have a very high red shift – should be possible from the ground.

Supermassive clusters of stars would also be more easily scrutinized using the technique, as images taken in a single pointing of the telescope on different nights would allow astronomers to understand just which stars are part of the cluster and which are not gravitationally bound.

The results of the team’s efforts was published in the Astrophysical Journal in 2009, and the original paper is available here on Arxiv.

Source: Eurekalert, Arxiv paper

July 29, 2010January 20, 2016 by Nancy Atkinson

Antarctic Observatory Finds Weird Pattern of Cosmic Rays

This "skymap," generated in 2009 from data collected by the IceCube Neutrino Observatory, shows the relative intensity of cosmic rays directed toward the Earth’s Southern Hemisphere. Researchers from UW-Madison and elsewhere identified an unusual pattern of cosmic rays, with an excess (warmer colors) detected in one part of the sky and a deficit (cooler colors) in another. Photo: courtesy IceCube collaboration

From a University of Wisconsin press release:

Though still under construction, the IceCube Neutrino Observatory at the South Pole is already delivering scientific results — including an early finding about a phenomenon the telescope was not even designed to study.

IceCube captures signals of notoriously elusive but scientifically fascinating subatomic particles called neutrinos. The telescope focuses on high-energy neutrinos that travel through the Earth, providing information about faraway cosmic events such as supernovas and black holes in the part of space visible from the Northern Hemisphere.
Continue reading “Antarctic Observatory Finds Weird Pattern of Cosmic Rays”

July 28, 2010December 24, 2015 by Nancy Atkinson

Stunning New Image of Wolf-Rayet Star and the Carina Nebula

The Carina Nebula around the Wolf–Rayet star WR 22. Credit: ESO

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Massive stars live fast and die young. But they are also beautiful. This amazingly spectacular new image from ESO shows the brilliant and unusual star Wolf-Rayet 22 nestled within billowing, colorful folds of the Carina Nebula. WR 22 is one of many exceptionally hot and brilliant stars contained by the beautiful Carina Nebula (also known as NGC 3372), a huge region of star formation in the southern Milky Way. The image was captured by ESO’s Wide Field Imager at the La Silla Observatory in Chile.

Wolf–Rayet stars are named after the two French astronomers who first identified them in the mid-nineteenth century, and WR 22 is one of the most massive ones we know of. It is a member of a double star system and has been measured to have a mass at least 70 times that of the Sun. Although the star lies over 5000 light-years from the Earth, it is so bright that it can just be faintly seen with the unaided eye under good conditions.

The colorful backdrop of the Carina Nebula is created by the interactions between the intense ultraviolet radiation coming from WR 22 and other hot massive stars within the nebula, and the vast gas clouds, mostly hydrogen, from which they formed. The central part of this enormous complex of gas and dust lies off the left side of this picture as can be seen in image another image on the ESO website. This area includes the famous star Eta Carinae, one of the most massive stars and unstable stars in the universe.

For more info, and larger images for downloads (need a new desktop background?) see this ESO webpage.

July 22, 2010December 24, 2015 by Nicholos Wethington

Most Massive Star Discovered: Over 300 Suns at Birth!

Zooming in on a giant: the Tarantula Nebula in the visible light on the left, a zoomed-in image of the location of R 136 in the center panel, and the R 136 cluster in the lower right of the last panel. Image Credit:ESO/P. Crowther/C.J. Evans

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Often, writing about astronomy tends to mirror the job of those writing for the Guinness Book of World Records – just when you think a record is practically unbeatable, somebody else appears to show up the previous record-holder. This is surely the case with the stellar heavyweight (er, “heavymass”) R 136a1, which has been shown by data taken using the European Southern Observatory’s Very Large Telescope and the Hubble Space Telescope to tip the stellar scales at 265 times the mass of our Sun. What’s even more impressive is that R 136a1 has lost mass over the course of its lifetime, and likely was about 320 solar masses at birth. That deserves a “Yikes!”

R 136a1 lies in a cluster of young, massive stars with hot surface temperatures that is located inside the Tarantula Nebula. The Tarantula Nebula is nested inside the Large Magellanic Cloud, one of the Milky Way’s closest galactic neighbors, 165,000 light-years away. The cluster is called RMC 136a (or more commonly referred to as R136), and in addition to the whopper that is R 136a1, there are three other stars with masses at birth in the 150 solar mass range.

Extremely massive stars like R 136a1 were previously thought to be unable to form, posing a challenge to stellar physicists as to just how this behemoth came about. It’s possible that it formed by itself in the relatively dense gas and dust of the R136 cluster, or that multiple smaller stars merged to create the larger star at some point early on in its lifetime.

If breaking the mass record weren’t enough, R136a1 also happens to be the most luminous star ever discovered, with an output of energy that is over 10 million times that of the Sun. If you want to learn more about how astronomers determine the mass and luminosity of stars, here is an excellent and thorough introduction to the subject.

To validate the models used in determining the mass and luminosity of the stars in R136, the team of astronomers led by Paul Crowther, Professor of Astrophysics at the University of Sheffield, used the VLT to examine NGC 3603, a closer stellar nursery. NGC 3603 is only 22,000 light years away, and two of the stars in that cluster are in a binary system, which allowed the team to measure their masses.

A comparison of the smallest stars (red dwarfs), Sun-like stars, blue dwarfs, and the most massive star ever discovered, R 136a1. Image Credit: ESO/M. Kornmesser

We are lucky to have observed this extremely massive star, as the rule for the most massive stars is, “Live fast, die young.” The more massive a star is, the faster it churns through the fuel that powers its increased luminosity. Our Sun, which has a medium amount of mass in relation to the two extremes, will last for around for about 10 billion years. Smaller, red dwarf stars can last trillions of years, while large stars on the scale of R 136a1 only glimmer in all of their brilliance for millions of years.

What will happen to R 136a1 at the end of its life? Stars with a mass of over 150 Suns ultimately explode in a light show of staggering proportions generated by what’s called a pair-instability supernova. For more on this phenomenon, check out this article from Universe Today from last year.

Source: ESO press release

A nod and a snarky wink to Genevieve Valentine

July 20, 2010December 24, 2015 by Ryan Anderson

WISE Mission Completes All-sky Infrared Survey

This view of the Pleiades star cluster is a composite of hundreds of WISE images, a tiny fraction of all those collected to complete the full-sky survey. Image credit: NASA/JPL-Caltech/UCLA

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If you take a lot of digital pictures, you’re probably familiar with the frustration of keeping track of dozens of files, and always running out of hard drive space to store them. Well, the scientists and engineers on NASA’s Wide-field Infrared Survey Explorer (WISE) mission have no pity for you. Their spacecraft just finished photographing the entire sky in exquisite detail: a total of 1.3 million photos.

“The eyes of WISE have not blinked since launch,” said William Irace, the mission’s project manager at NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “Both our telescope and spacecraft have performed flawlessly and have imaged every corner of our universe, just as we planned.”

WISE surveys the sky in strips as it orbits the earth. It takes six months of constant observing to map the entire sky. By pointing at every part of the sky, astronomical surveys deliver excellent data covering both well-known objects and those that have never been seen before.

“WISE is filling in the blanks on the infrared properties of everything in the universe from nearby asteroids to distant quasars,” said Peter Eisenhardt of JPL, project scientist for WISE. “But the most exciting discoveries may well be objects we haven’t yet imagined exist.”

One example of a well-known object seen in new light by WISE is the Pleiades cluster: a group of young blue stars shrouded by dust that the cluster is currently passing through. In WISE’s false-color infrared vision, the hot stars look blue but the cooler dust clouds give off longer wavelengths of infrared light, causing them to glow in shades of yellow and green.

The WISE survey is particularly significant because such a wide range of objects in the universe are visible in infrared light. Giant molecular clouds glow in infrared light, as do brown dwarfs – objects that are bigger than planets but smaller than true stars. WISE can also see ultra-bright, extremely distant galaxies whose visible light has been stretched into the infrared by the expansion of the universe during its multi-billion-year journey.

The recently completed WISE survey also observed 100,000 asteroids in our solar system, many of which had never been seen before. 90 of the newly discovered asteroids are near-earth objects, whose orbits cross our own, making them potentially dangerous but also potential targets for future mission.

You might think that 1.3 million pictures would be plenty, but WISE will keep mapping the sky for another three months, covering half of the sky again and allowing astronomers to search for changes. The mission will end when the spacecraft’s solid hydrogen coolant finally runs out and the infrared detectors warm up (they don’t work as well when they are warm enough to emit the same wavelengths of infrared light that they are meant to detect).

But even as the telescope warms up, the astronomers on the WISE team will just be getting warmed up too. With nearly two million images, they will be busy making new discoveries for years to come.