While the universe is filled to the brim with galaxies, there's only one that we call home: the Milky Way galaxy. It's its own little universe, if you will, containing hundreds of billions of stars, dust and gas, all held in place by gravity. If you want to see it, just look up at the night sky. When the night is clear enough, the fuzzy patch of light stretching across the sky is the band of the Milky Way. In fact, almost all of what you see up there is part of our galaxy. Closer to the present moment, though, if you want to see more of the Milky Way, just step through this gallery.
The Milky Way galaxy is about 120,000 light years across. See the Milky Way from a different angle on the next page.
Image Credit: Davis Meltzer/National Geographic/Getty Images
A side view of the Milky Way galaxy. Next, you can see a radio map of the Milky Way.
Image Credit: E.L. Wright (UCLA), The COBE Project, DIRBE, NASA
Here's a radio map of the Milky Way showing the location of its major features. Our galaxy is the most prominent feature in the night sky -- in fact, technically, it's the only feature! Next, see pictures of the Milky Way that were taken from here on Earth.
Image Credit: Image courtesy NASA
The Milky Way, from the bright star Sirius in the upper right corner all the way down to Eta Carina, the red nebula visible on the horizon, as seen from the Florida Keys. You can see more pictures of the night sky on the next page.
Image Credit: Tony Hallas/Science Fiction/Getty Images
A spruce tree in Cannon Beach, Ore., silhouetted against Milky Way star field. You can see a stunning view of the sun, one of millions of stars in our galaxy, on the next page.
Image Credit: Jim Ballard/Photographers Choice/Getty Images
The sun is just one of many stars in the Milky Way. How does the sun compare to other stars in the galaxy?
Image Credit: NASA/Getty Images
The sun looks like any other star in the galaxy from afar.
Image Credit: Davis Meltzer/National Geographic/Getty Images
Earth's place in the Milky Way makes it impossible for us to get a view of what the whole galaxy looks like, even though we have a pretty good idea. What we can do, though, is pick a galaxy that's similar in its shape and structure to the Milky Way. Like this one, for example: NGC 3949. It's a spiral galaxy, like ours, and has a blue disk of outer, younger stars and a bright bulge at the center comprised of older stars. So, you could look at this galaxy and not be out of line to say it could pass for a portrait of our own Milky Way. NGC 3949 is some 50 million light years from Earth, and it's thanks to NASA's Hubble Space Telescope that we have this image.
Image Credit: NASA/ESA/Hubble Heritage Team
Did you know there's a big black hole at the center of our galaxy? This image from NASA"s Chandra X-ray telescope shows the center of the Milky Way. The location of the black hole, known as Sagittarius A*, or Sgr A*, is indicated with an arrow. Scientists discovered that Sgr A* released a powerful flare some 300 years ago, but it has been relatively quiet since then.
Image Credit: NASA/CXC/MIT/Frederick K. Baganoff et al.
The Hubble Space Telescope decided to do a photo shoot with the oldest burned-out stars in the Milky Way, and here's a glimpse at some of its subjects. These seriously old white dwarf stars were born some 12 to 13 billion years ago. Such star clusters were among the first building blocks -- forming the hub -- of what we know today as the Milky Way. This particular shot is a part of globular cluster M4, the cluster closest to Earth.
Image Credit: NASA and H. Richer (University of British Columbia)
Here we see what happens when the Hubble Space Telescope, the Spitzer Space Telescope and the Chandra X-ray Observatory work together. The three collaborated to produce this composite image of the central region of the Milky Way. Because the observation systems used infrared and X-ray light, we get to see through the otherwise obscuring dust and get a look at the core of the Milky Way. The center of the galaxy is in the bright, white region to the right of, and just below, the middle of the image. And this is just a smidge of what's out there! The entire image width covers about one-half of a degree, about the same angular width as the full moon.
Image Credit: X-ray: NASA/CXC/UMass/D. Wang et al.; Optical: NASA/ESA/STScI/D.Wang et al.; IR: NASA/JPL-Caltech/SSC/S.Stolovy
Remember the picture we saw a few frames back, of a galaxy like ours? Well, here's an artist's rendering of what our own galaxy might look like -- as viewed from the outside looking in. Our sun (about the center of the picture) is about 25,000 light years from the center of our galaxy. This illustration makes it easy to see why the Milky Way is called a spiral galaxy, as the successive spiral arms are plain to see. The yellow cone illustrates the part of our galaxy that NASA's Kepler spacecraft is roaming in search of habitable planets.
Image Credit: Jon Lomberg
The star shown here in the inset, time-lapse boxes is known as Hubble variable number one, or just V1. It makes its living in the outer portion of our next-door neighbor galaxy, Andromeda. This star in 1923 changed the direction of astronomy, as it changed our opinion of our Milky Way galaxy and its place in the cosmos. Early in the 20th century, most astronomers believed the Milky Way was the be-all end-all: simply an island universe, with nothing beyond it. What we now know as the separate galaxy of Andromeda back then was just a blurry patch of light dubbed "spiral nebulae." Some astronomers did, however, wonder if spiral nebulae might themselves be separate island universes. But they couldn't prove it, until Edwin Hubble observed V1 brightening and fading in a predictable pattern. The star assisted Hubble in making his determination that Andromeda was indeed outside our galaxy, answering the question of what to make of the spiral nebulae. NASA thought it appropriate for the space telescope named after Hubble himself take pictures of the important star. (Note its changing brightness over time in each inset, the characteristic originally observed by Hubble.)
Image Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)
Here we see the Heart and Soul nebulae. They're about 6,000 light years from Earth, and the nebulae make up a star-forming factory in a portion of the Perseus spiral arm of the Milky Way. On the right is the Heart nebula (formally designated IC 1805, but familiarly named for its resemblance to a human heart). To the left is the Soul nebula, which is also known as the Embryo nebula, IC 1848 or W5. The Heart and Soul nebulae reach out 580 light years across. (Even that enormous expanse covers just a small portion of the diameter of the Milky Way, which is roughly 100,000 light-years across.)
Image Credit: NASA/JPL-Caltech/UCLA
This image is a mosaic of the Lagoon nebula, taken by NASA's Wide-field Infrared Survey Explorer. It's composed of clouds of gas and dust, and new stars are forming there. This picture is looking in toward the center of the Milky Way, located in the constellation Sagittarius. That's where the Lagoon nebula lives. It's a favorite target for amateur astronomers because it can be easily seen with binoculars or a small telescope.
Image Credit: NASA/JPL-Caltech/UCLA
Meet the Pistol Nebula, what NASA calls one of the intrinsically brightest stars in our galaxy. It's the bright, white dot in the center of this image, captured by the Hubble Space Telescope. Hubble's Infrared Camera apparatus was needed to take this picture, because the star is hidden at the center of the Milky Way, behind obscuring dust. Hubble penetrated the dust to reveal the star, which is glowing with the radiance of 10 million suns. The star is 25,000 light-years away, in the direction of the constellation Sagittarius. It's so bright that, even despite its vast distance from us the star would still be visible to the naked eye from Earth, if not for the dust between it and us. Astronomers estimate the star may be 100 times more massive than our Sun.
Image Credit: NASA and Don F. Figer (UCLA)
Feel like you're seeing stars? Of course you are! It's the Omega Centauri star cluster, one of the largest and most massive globular star clusters in our Milky Way galaxy. Interestingly, this giant star city may have a medium-sized black hole at its core that is estimated to be roughly 40,000 times the mass of the sun. The black hole was discovered with NASA's Hubble Space Telescope and Gemini Observatory on Cerro Pachon in Chile. The Omega Centauri cluster is about 17,000 light-years from Earth. Globular clusters, in general, are giant globs of up to a million stars, gravitationally bound to each other. There are more than 200 globular clusters in the Milky Way. Next up, we'll check out a ring at the center of our galaxy.
Image Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)
Astronomers using the Herschel Space Observatory have found that a suspected ring at the center of our galaxy is warped, but they don't know why. This image is from Herschel, an infrared European Space Agency-led mission with input from NASA, shows the ring as a yellow loop that appears to have two lobes, highlighted here with a white ribbon overlay. The ring is a group of dense, cold gas and dust -- twisted so that part of it rises above and part below the plane of the Milky Way. Astronomers don't yet know how rings like this form in galaxies, but some theorize that they are due to gravitational disturbances with nearby galaxies. Meanwhile, in the gas that forms this ring, new stars are thought to be forming. This ring, by the way, isn't exactly small: It stretches over more than 300 light years, and it's about 15 degrees Kelvin (minus 433 degrees Fahrenheit). The warmest material in this picture is blue, and the coldest is red. Next, we'll look at some (relative) baby pictures from the Milky Way.
Image Credit: ESA/NASA/JPL-Caltech
Here we see thousands of young stars in the giant nebula called NGC 3603, among the most massive young star clusters in the Milky Way. NGC 3603 is about 20,000 light-years away from Earth. We'll look at another young star cluster in our next picture -- this one of quintuplets.
Image Credit: NASA, ESA, and the Hubble Heritage (STScI/AURA)-ESA/Hubble Collaboration
Peering through 25,000 light years of dust and stars, the Hubble Space Telescope caught this sparkling-clear view of the Quintuplet Cluster. It's one of the largest young star factories in the Milky Way and it's less than 100 light years from the center of the galaxy. Boasting the brightest star yet seen in the galaxy (the Pistol star), the Quintuplet Cluster is about 10 times the size of other young star clusters in the galaxy, but it has an unkind fate awaiting it in just a few million years: That's when gravitational forces in the core of the Milky Way will tear the cluster apart. So, while it's fate is sealed, at least it's burning brightly while it's alive. And, speaking of fate, our next picture gives us a preview of what may be in store for the Milky Way several billion years from now.
Image Credit: NASA
This image shows us the best picture yet of the merging "Antennae Galaxies," which started to impinge on each others' turf a few hundred million years ago. That makes them one of the nearest and youngest examples we have of galaxies smashing into each other. The orange blobs to the left and right of the image center are the cores of the original, separate galaxies -- they're mainly comprised of old stars. Nearly half of the fainter objects in the image, though, are young clusters holding tens of thousands of stars. Many of the young clusters won't survive more than about 10 million years, with the majority of the rest of them dispersing. But around 100 will live on to make the kinds of clusters we see in our own Milky Way galaxy. This picture gives us a hint of how things might look one day, billions of years from now, when the Milky Way collides with our neighbor Andromeda. Next we'll look at nurseries in the clouds!
Image Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)-ESA/Hubble Collaboration
WISE, NASA's Wide-field Infrared Survey Explorer, took this picture of Barnard 3 -- a.k.a., IRAS Ring G159.6-18.5 -- that is bathed in bright green and red dust clouds. These kinds of interstellar clouds are stellar nurseries, incubating newborn baby stars. The green ring is tiny particles of warm dust that's similar to smog on Earth, while the red cloud at the center is most probably comprised of dust that's more metallic in composition, and cooler, than its surroundings. If you look closely in the center of the red cloud, you'll see HD 278942, a star so bright that astronomer's think it's the probable cause of the surrounding ring's glow. Next up, we'll check out an example of what gets left behind after a stellar explosion.
Image Credit: NASA/JPL-Caltech/UCLA
Here we see a ribbon of gas floating along in the Milky Way. While it might look to candy fans like a long piece of galactic red licorice, it's actually a very thin section of a supernova remnant left over from a stellar explosion that went boom more than 1,000 years ago, on or around May 1, 1006 A.D. People from Africa to the Far East saw and recorded the appearance of light from what is now called SN 1006, a supernova explosion caused by the death of a white dwarf star about 7,000 light years away. It was likely the brightest star ever to be witnessed by humans, out-brightening Venus as the brightest non-moon object in the night sky. It could even be seen during the day time for weeks, and it remained visible to the naked eye for at least two and a half years before fading away. Amazingly enough, even after all of that time has passed, SN 1006 -- about 60 light years in diameter -- is still expanding at about 6 million miles an hour (9.7 million kilometers per hour).
Image Credit: NASA/STScI
Here's a picture of three nebulae located in the Perseus constellation. NGC 1941 is on the right, BFS 34 is in the middle and SH 2-209 is on the left. They might look close to each other, but in reality they're not exactly over-the-fence chatting neighbors. NGC 1491 and BFS 34 are part of the same cloud complex about 10,700 light years away, in the Perseus arm of the Milky Way. SH 2-209 is farther away -- about 16,000 light years out, making its living in the outer arm of the Milky Way. Just because they're in the same picture doesn't mean they're close friends. Next up, we'll see the possible solution to a Milky Way mystery.
Image Credit: NASA/JPL-Caltech
Scientists have detected mysterious X-ray flares coming from the region of Sagittarius A*, which, as we learned earlier, contains a supermassive black hole at the center of our galaxy. A study suggests there's a cloud around Sagittarius A* that holds hundreds of trillions of asteroids and comets that have been torn away from their parent stars. So whenever an asteroid of 6 miles (9.7 kilometers) or greater in radius gets eaten by the black hole, the X-ray flares occur. This illustration depicts some of these asteroids on their way to being vaporized.
Image Credit: NASA/CXC/M.Weiss
This artist's depiction shows the "Arches" star cluster -- from deep inside the hub of the Milky Way. It's hidden from our direct view, thanks to the dusty core of our galaxy, so the illustration is based on observations from the Hubble telescope combined with data from ground-based observatories. The enormous cluster is about 25,000 light years away and holds the current title for densest group of young stars in the Milky Way. Some 2,000 stars are estimated to be in this cluster. Next, we'll meet some stars that seem to have managed to do what our own Hollywood stars would love to do: look younger than they are!
Image Credit: Artist's Concept/NASA/ESA/STScI
The pop-out box in this picture isolates a rare breed of star that scientists call blue stragglers. They're in the hub of the Milky Way and are the first detected within the galaxy's bulge. They're called "blue stragglers" because they appear to lag behind in the star aging process -- looking younger than the other stars in the population from which they grew up. Blue stragglers have been seen in lots of faraway star clusters, and among some nearby stars, but they had never been seen inside the core of the Milky Way. It's unclear to scientists exactly how blue stragglers manage their youthful appearance. One theory is that they emerge from binary pairs of stars. As the more massive star in the pair evolves and expands, the smaller star picks up material from its companion. This stirs up hydrogen fuel and causes the growing star to undergo nuclear fusion at a faster rate -- so it burns hotter and bluer, making itself look like a massive young star.
Image Credit: NASA, ESA, W. Clarkson (Indiana University and UCLA), and K. Sahu (STScl)
Scientists have recently discovered that the Milky Way's spiral structure is dominated by only two arms wrapping off the ends of a central bar of stars. Prior thinking on the subject pegged our galaxy as having four major arms. This artist's illustration shows the new view of the Milky Way. The two major arms (Scutum-Centaurus and Perseus) can be seen attached to the ends of the thick central bar of stars, while two (now-de-emphasized) minor arms (called Norma and Sagittarius) are less distinct, stretching out between the major arms. The major arms have the most young and old stars; the minor arms are mostly gas and some pockets of star-forming activity. Our home star, the sun, lies near a small, partial arm called the Orion Arm, or Orion Spur, which lives between the Sagittarius and Perseus arms.
Image Credit: NASA/JPL-Caltech
We'll close out our gallery with this look at the region surrounding the center of the Milky Way. Normally, it's next to impossible to see the center of the galaxy in visible light, but infrared light cuts through the dust, as we have seen in other places in our gallery. The region pictured here is enormous almost beyond comprehension, with a horizontal span of 2,400 light years (5.3 degrees) and a vertical span of 1,360 light years (3 degrees). Although the bulk of the objects in this picture live near the Milky Way center, the features above and below the galactic plane are closer to Earth.
Now that you've seen our Milky Way Pictures, check out our list of the Top 10 Cosmological Achievements!
Image Credit: NASA/JPL-Caltech
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