What Does a Nebula Sound Like?

What do things sound like out in the cosmos? Of course, sound waves can’t travel through the vacuum of space; however, electromagnetic waves can. These electromagnetic waves can be recorded by devices called spectrographs on many of the world’s most powerful telescopes. Astronomer Paul Francis from the Australian National University has used some of these recordings and converted them into sound by reducing their frequency 1.75 trillion times to make them audible, as the original frequencies are too high to be heard by the human ear.

“This allows us to listen to many parts of the universe for the first time,” Francis wrote on his website. “We can hear the song of a comet, the chimes of stars being born or dying, the choir of a quasar eating the heart of a galaxy, and much more.”
Continue reading “What Does a Nebula Sound Like?”

Spitzer’s Stunning New View of the North American Nebula


In visible light, the North American nebula resembles its namesake continent. But looking at it in the infrared spectrum, a whole new perspective explodes into view. Clouds of dust and gas come to life, as light from massive young star heats and shape the clouds, and dramatic clusters of baby stars which can only be seen in infrared burst into view.

“One of the things that makes me so excited about this image is how different it is from the visible image, and how much more we can see in the infrared than in the visible,” said Luisa Rebull of NASA’s Spitzer Science Center at the California Institute of Technology, Pasadena, Calif. Rebull is lead author of a paper about the observations, accepted for publication in the Astrophysical Journal Supplement Series. “The Spitzer image reveals a wealth of detail about the dust and the young stars here.”

Rebull and her team have identified more than 2,000 new, candidate young stars in the region. There were only about 200 known before. Because young stars grow up surrounded by blankets of dust, they are hidden in visible-light images. Spitzer’s infrared detectors pick up the glow of the dusty, buried stars.

This new view of the North American nebula combines both visible and infrared light observations, taken by the Digitized Sky Survey and NASA's Spitzer Space Telescope, respectively, into a single vivid picture. Image credit: NASA/JPL-Caltech

Combing infrared data with light from other parts of the spectrum gives astronomers a complete picture of star formation. Each different combination of observations gives insights into star formation.

But in Spitzer’s infrared view, the continent disappears. Instead, a swirling landscape of dust and young stars comes into view.

In this image, astronomers can see stars at all stages of life, from the early years when it is swaddled in dust to early adulthood, when it has become a young parent to a family of developing planets. Sprightly “toddler” stars with jets can also be identified in Spitzer’s view.

“This is a really busy area to image, with stars everywhere, from the North American complex itself, as well as in front of and behind the region,” said Rebull. “We refer to the stars that are not associated with the region as contamination. With Spitzer, we can easily sort this contamination out and clearly distinguish between the young stars in the complex and the older ones that are unrelated.”

There are a couple of mysteries about the North American Nebula still to be solved: astronomers think there must be more stars in the “Gulf of Mexico” region that must dominate the nebula and provide the main source of “power.” There is a dark tangle of clouds there that even Spitzers powerful infrared eyes can’t penetrate, but some light appears to be coming from behind that region, in the same way that sunlight creeps out from behind a rain cloud.

The nebula’s distance from Earth is also a mystery. Current estimates put it at about 1,800 light-years from Earth. Spitzer will refine this number by finding more stellar members of the North American complex.

See more info on the JPL website, where you can download full resolution versions of the images seen here, and more views of the North American nebula.

Ambitious Survey Spots Stellar Nurseries


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.

WISE Covers the Heart and Soul of Infrared Astronomy


In about six months’ time, NASA’s WISE mission, the Wide-field Infrared Survey Explorer, has captured almost a million images, covering about three-quarters, or 30,000 square degrees, of the sky. At the 216th American Astronomical Society meeting today, astronomers released a new mosaic of two bubbling clouds in space, known as the Heart and Soul nebulae.

“This image actually has two hearts; one is a Valentine’s Day heart, and the other is a surgical heart that you have in your body,” said Ned Wright of the University of California, Los Angeles who presented the new picture. “This new image demonstrates the power of WISE to capture vast regions. We’re looking north, south, east and west to map the whole sky.”

To make this huge mosaic WISE stared at this region of space which lies about 6,000 light-years away in the constellation Cassiopeia, for 3.5 hours of total exposure time, taking 1,147 images.

Both these nebulae are massive star-making factories, marked by giant bubbles blown into surrounding dust by radiation and winds from the stars. The infrared vision of WISE allows it to see into the cooler and dustier crevices of clouds like these, where gas and dust are just beginning to collect into new stars.

WISE will complete its first map of the sky in July 2010, and then spend the next three months surveying much of the sky a second time, before the solid-hydrogen coolant needed to chill its infrared detectors runs dry. Wright said the first installment of the public WISE catalog will be released in summer 2011.
Wright marveled at how in the span of his career he has gone from observing in just 4 pixels to now observing with WISE in almost 4 million pixels.

“It’s been an amazing progress in IR astronomy, with cameras growing by a factor of a million in power in just a few decades,” he said.

Screen shot from Wright's presentation at the AAS meeting showing how much of the sky WISE has covered. The small green box shows the area of the Heart and Soul nebulae.

Spotting NEO’s

One goal of the WISE mission is to study asteroids throughout our solar system and to find out more about how they vary in size and composition. Infrared helps with this task because it can get better size measurements of the space rocks than visible light.

So far, WISE has observed more than 60,000 asteroids, most of which lie in the main belt, orbiting between Mars and Jupiter. About 11,000 of these objects are newly discovered, and about 50 of them belong to a class of near-Earth objects, which have paths that take them within about 48 million kilometers (30 million miles) of Earth’s orbit.

“As WISE is orbiting the Earth, we are sweeping through the solar system like radar, and building up a map of what the solar system looks like in near infrared, looking for Near Earth Objects,” said astronomer Tommy Grav of Johns Hopkins University.

Grav told Universe Today so far there haven’t been any big surprises in the amount of NEOs the WISE team is finding. “We haven’t done full analysis of all the data WISE has sent back, but we’re finding about what we expected. We’re right in the ballpark of what we expected to find.”

The mission also studies the Trojans, asteroids that run along with Jupiter in its orbit around the sun in two packs — one in front of and one behind the gas giant. It has seen more than 800 of these objects, and by the end of the mission, should have observed about half of all 4,500 known Trojans. The results will address dueling theories about how the outer planets evolved.

“We can basically confirm and fill in the gap between ground based observations and the Spitzer Space Telescope’s observations of the Trojan asteroids,” Grav said.

Grav said WISE is an outstanding observatory. “We’ve basically done in six months what it took over 100 years to do in the optical.”

Sources: NASA, AAS press conference

Young Stars Blast a Hole in Space


There is a black patch of space in NGC 1999, and for years astronomers have thought it was just a dense cloud of gas and dust, blocking light from passing through. But the Herschel infrared space telescope – which has the ability to peer into these dense clouds — has made an unexpected discovery. This black patch is actually a hole that has been blown in the side of the nebula by the jets and winds of gas from the young stellar objects in this region of space. “No-one has ever seen a hole like this,” said Tom Megeath, of the University of Toledo in the USA. “It’s as surprising as knowing you have worms tunneling under your lawn, but finding one morning that they have created a huge, yawning pit.”

Any previous descriptions of NCG 1999 said that the ominous dark cloud in the center was actually a condensation of cold molecular gas and dust so thick and dense that it blocks light. And astronomers had no reason to believe otherwise, until Herschel’s powerful infrared eyes took a look from space.

A Hubble image of NCG 1999 showing the dark patch. Credit: Hubble Heritage Team (STScI) and NASA

When Herschel looked in the direction of this nebula to study nearby young stars, the cloud continued to look black. But, that should not be the case. Herschel’s infrared eyes are designed to see into such clouds. Either the cloud was immensely dense or something was wrong.

Investigating further using ground-based telescopes, astronomers found the same story however they looked: this patch looks black not because it is a dense pocket of gas but because it is truly empty. Something has blown a hole right through the cloud.

Stars are born in dense clouds of dust and gas. Although jets and winds of gas have been seen coming from young stars in the past, it has always been a mystery exactly how a star uses these to blow away its surroundings and emerge from its birth cloud. With Herschel, this may be the first time we can see this process.

The astronomers think that the hole must have been opened when the narrow jets of gas from some of the young stars in the region punctured the sheet of dust and gas that forms NGC 1999. The powerful radiation from a nearby mature star may also have helped to clear the hole. Whatever the precise chain of events, it could be an important glimpse into the way newborn stars disperse their birth clouds.

Source: ESA

Herschel Spots Previously Unseen Stars in Rosette Nebula

Infrared image of the Rosette molecular cloud by the Herschel space observatory. Credits: ESA/PACS & SPIRE Consortium/HOBYS Key Programme Consortia

Wow, what a gorgeous new image from the Herschel telescope – and what makes this especially stunning is that we’ve never seen these stars before! And these stars in the Rosette Nebula are huge, as each one is up to ten times the mass of our Sun. “High-mass star-forming regions are rare and further away than low-mass ones,” said Frédérique Motte, from the Laboratoire AIM Paris-Saclay, France. “So astronomers have had to wait for a space telescope like Herschel to reveal them.”
Continue reading “Herschel Spots Previously Unseen Stars in Rosette Nebula”

New VISTA of Orion


Oh-oh-oh Orion! The new VISTA (Visible and Infrared Survey Telescope for Astronomy) infrared survey telescope has used its huge field of view to show the full splendor of the Orion Nebula. With its infrared eyes, it has peered deeply into dusty regions that are normally hidden to expose the curious behavior of the very active young stars buried there.

VISTA is the latest addition to ESO’s Paranal Observatory. It is the largest survey telescope in the world and is dedicated to mapping the sky at infrared wavelengths. The large (4.1-metre) mirror, wide field of view and very sensitive detectors make VISTA a unique instrument. This dramatic new image of the Orion Nebula illustrates VISTA’s remarkable powers.

The Orion Nebula is about 1,350 light-years from Earth. Although spectacular when seen through an ordinary telescope, what can be seen using visible light is only a small part of a cloud of gas in which stars are forming. Most of the action is deeply embedded in dust clouds and to see what is really happening astronomers need to use telescopes with detectors sensitive to the longer wavelength radiation that can penetrate the dust. VISTA has imaged the Orion Nebula at wavelengths about twice as long as can be detected by the human eye.

Four highlights of the new VISTA image of Orion. Credit: ESO

On the upper-left, the central region of VISTA’s view of the Orion Nebula is shown, centered on the four dazzling stars of the Trapezium. A rich cluster of young stars can be seen here that is invisible in normal, visible light images. In the lower-right panel the part of the nebula to the north of the center is shown. Here there are many young stars embedded in the dust clouds that are only apparent because their infrared glow can penetrate the dust and be detected by the VISTA camera. Many outflows, jets and other interactions from young stars are apparent, seen in the infrared glow from molecular hydrogen and showing up as red blobs. On the upper-right, a region to the west of center is shown. Here the fierce ultraviolet light from the Trapezium is sculpting the gas clouds into curious wavy shapes. A distant edge-on spiral galaxy is also seen shining right through the nebula. At the lower-left a region south of the center is shown. Each extract covers a region of sky about nine arcminutes across.

All these features are of great interest to astronomers studying the birth and youth of stars.

Source: ESO

Pretty Picture of the Week: NGC 3603

This magnificent image of the giant stellar nursery surrounding NGC 3603 was taken by the Very Large Telescope at Cerro Paranal, Chile. This nebula is a starburst region, a huge star-making factory where stars form frantically from the nebula’s billowing clouds of gas and dust. It is located 22,000 light-years away from the Sun, and is the closest region of this kind known in our galaxy. Thousands of stars inhabit this region, with most having masses similar to that of our sun. But other stars are some of the most spectacular and massive stars around. In fact, one star, NGC 3603 A1, is the most massive star ever “weighed.” Several blue supergiant stars crowd into a volume of less than a cubic light-year, along with three so-called Wolf-Rayet stars — extremely bright and massive stars that will do the supernova gig relatively soon. The Bad Astronomer tells it way better than I, so go check out his gigantisized blog post.

Source: ESO

Stunning New Look at the Cat’s Paw Nebula


This striking new image shows the vast cloud of gas and dust known as the Cat’s Paw Nebula or NGC 6334. This glowing nebula resembles a gigantic pawprint of a celestial cat out on an errand across the Universe. This complex region of gas and dust, where numerous massive stars are born, lies near the heart of the Milky Way galaxy, about 5500 light-years away. It covers an area on the sky slightly larger than the full Moon. The whole gas cloud is about 50 light-years across.

This new portrait of the Cat’s Paw was created from images taken with the Wide Field Imager instrument at the 2.2-metre MPG/ESO telescope at the La Silla Observatory in Chile, combining images taken through blue, green and red filters, as well as a special filter designed to let through the light of glowing hydrogen.

The nebula appears red because its blue and green light are scattered and absorbed more efficiently by material between the nebula and Earth. The red light comes predominantly from hydrogen gas glowing under the intense glare of hot young stars.

Particularly striking is the red, intricate bubble in the lower right part of the image. This is most likely either a star expelling large amount of matter at high speed as it nears the end of its life or the remnant of a star that already has exploded.

NGC 6334 is one of the most active nurseries of massive stars in our galaxy and has been extensively studied by astronomers. The nebula conceals freshly minted brilliant blue stars — each nearly ten times the mass of our Sun and born in the last few million years. The region is also home to many baby stars that are buried deep in the dust, making them difficult to study. In total, the Cat’s Paw Nebula could contain several tens of thousands of stars.

Click here to see videos that pan and zoom into this stunning new image.

Nebula Wallpaper

Nebula Wallpaper

Want a nebula wallpaper to put as the background image of your computer desktop? Here’s a handful of nebula images. To make any of them your computer’s background image, just click on the image to see a larger version. Then right-click on the image and choose to set the image as your desktop background.

The nebula wallpaper is the Flame Nebula, captured by the European Southern Observatory. Also known as NGC 2024, it’s a famous nebula located about 1,500 light-years away in the constellation of Orion. The bright star at the top of the image is Alnitak, one of the belt stars of Orion.

Crab Nebula

This is a wallpaper image of the Crab Nebula taken by the Hubble Space Telescope. Also known as M1, the Crab Nebula is the results of a supernova explosion that occurred almost 1000 years ago. Astronomers in 1054 AD reported a star brighting in the sky, and lasting for a few weeks before it dimmed again. That was the supernova that went on to create the Crab Nebula.

Butterfly Nebula

This is a wallpaper of the Butterfly Nebula (or NGC 6302) captured by Hubble. This is a planetary nebula, the result of a dying star blasting out its outer layers into space. This is what our own Sun might do in about 7 billion years from now after it becomes a red giant star.

Ring Nebula

This is Hubble Space Telescope image of the Ring Nebula, also known as M57. It’s actually a planetary nebula, where the outer layers of a dying star are puffed out into space. The Ring Nebula is located about 4000 light-years away, and measures about 500 times larger than the Solar System.

Carina Nebula

This is the Carina Nebula, photographed by the Hubble Space Telescope. This is just one pillar of gas and dust in the nebula, measuring 2 light-years across. It’s located about 7,500 light years from Earth.

We’ve written many articles about nebulae for Universe Today. Here’s an article about dust in the Iris Nebula, and here’s an article about Hubble images of the Helix Nebula.

If you’d like more information on nebulae, check out NASA’s Photo Gallery of Nebulae, and here’s a link to the Hubblesite Homepage for recent stories and images.

We’ve recorded an episode of Astronomy Cast all about nebulae. Listen here, Episode 111: Nebulae.