Hubble Spies Tiny, Ancient ‘Ghost Galaxies’

These Hubble images show the dim, star-starved dwarf galaxy Leo IV. The image at left shows part of the galaxy, outlined by the white rectangular box. The box measures 83 light-years wide by 163 light-years long. The few stars in Leo IV are lost amid neighboring stars and distant galaxies. A close-up view of the background galaxies within the box is shown in the middle image. The image at right shows only the stars in Leo IV. The galaxy, which contains several thousand stars, is composed of sun-like stars, fainter, red dwarf stars, and some red giant stars brighter than the sun. Credit: NASA, ESA, and T. Brown (STScI)

They’re out there; tiny, extremely faint and incredibly ancient dwarf galaxies with so few stars that scientists call them ‘ghost galaxies.’ NASA’s Hubble Space Telescope captured images of three of these small-fry galaxies in hopes of unraveling a mystery 13 billion years in the making.

Astronomers believe these tiny, ghost-like galaxies spotted alongside the Milky Way Galaxy are among the oldest, tiniest and most pristine galaxies in the Universe. Hubble views reveal that their stars share the same birth date. The galaxies all started forming stars more than 13 billions years ago but then abruptly stopped within just one billion years after the Universe was born.

“These galaxies are all ancient and they’re all the same age, so you know something came down like a guillotine and turned off the star formation at the same time in these galaxies,” said Tom Brown of the Space Telescope Science Institute in Baltimore, Md., the study’s leader. “The most likely explanation is reionization.”

Reionization of the Universe began in the first billion years after the Big Bang. During this time, radiation from the first stars knocked electrons off hydrogen atoms, ionizing the hydrogen gas. This process also allowed hydrogen gas to become transparent to ultraviolet light. This same process may also have squashed star-making in dwarf galaxies, such as those in Brown’s study. These galaxies are tiny cousins to star-making dwarf galaxies near the Milky Way. And because of their small size, just 2,000 light-years across, they were not massive enough to shield themselves from the harsh ultraviolet light of the early Universe which stripped away their meager supply of hydrogen gas, leaving them unable to make new stars.

Astronomers proposed many reasons for the lack of stars in these galaxies in addition to the reioniation theory. Some scientists believed internal events such as supernovae blasted away the gas needed to create new stars. Others suggested that the galaxies simply used up their supply of hydrogen gas needed to make stars.

Brown measured the stars’ ages by looking at their brightness and colors. The stellar populations in these fossil galaxies range from a few hundred to a few thousand stars; some sun-like, some red dwarfs and some red stars larger than our Sun. When evidence showed that the stars were indeed ancient, Brown enlisted the help of Hubble’s Advanced Camera for Surveys to burrow deep within six galaxies to determine when they were born. So far, the team has finished analyzing data for three; Hercules, Leo IV and Ursa Major. The galaxies lie between 330,000 light-years to 490,000 light-years. For comparison, Brown compared the galaxies’ stars with those found in M92, a 13 billion-year-old globular cluster located about 26,000 light-years from Earth. He found they are of similar age.

“These are the fossils of the earliest galaxies in the universe,” Brown said. “They haven’t changed in billions of years. These galaxies are unlike most nearby galaxies, which have long star-formation histories.”

Brown’s discovery could help explain the so-called “missing satellite problem.” Astronomers have observed only a few dozen dwarf galaxies around the Milky Way while computer simulations predict thousands should exist. But perhaps they do exist. The Sloan survey found more than a dozen tiny, star-starved galaxies in the Milky Way’s neighborhood while scanning just a portion of the sky. Astronomers think that dozens more ultra-faint galaxies may lurk undetected with the possibility of thousands of even smaller dwarfs containing virtually no stars.

The tiny galaxies may be star-deprived but they still have an abundance of dark matter, the framework upon which galaxies are built. Normal dwarf galaxies near the Milky Way Galaxy contain ten times more dark matter than ordinary visible matter. Brown explains that these tiny galaxies are now islands of mostly dark matter, unseen for billions of years until astronomers began finding them in the Sloan Survey.

Brown’s results appear in the July 1 issue of the Astrophysical Journal Letters.

Image caption 1: These Hubble images show the dim, star-starved dwarf galaxy Leo IV. The image at left shows part of the galaxy, outlined by the white rectangular box. The box measures 83 light-years wide by 163 light-years long. The few stars in Leo IV are lost amid neighboring stars and distant galaxies. A close-up view of the background galaxies within the box is shown in the middle image. The image at right shows only the stars in Leo IV. The galaxy, which contains several thousand stars, is composed of sun-like stars, fainter, red dwarf stars, and some red giant stars brighter than the sun. Credit: NASA, ESA, and T. Brown (STScI)

Image caption 2: These computer simulations show a swarm of dark matter clumps around our Milky Way galaxy. Some of the dark-matter concentrations are massive enough to spark star formation. Thousands of clumps of dark matter coexist with our Milky Way galaxy, shown in the center of the top panel. The green blobs in the middle panel are those dark-matter chunks massive enough to obtain gas from the intergalactic medium and trigger ongoing star formation, eventually creating dwarf galaxies. In the bottom panel, the red blobs are ultra-faint dwarf galaxies that stopped forming stars long ago. Credit: NASA, ESA, and T. Brown and J. Tumlinson (STScI)

Sifting Starlight, Finding New Worlds

These two images show HD 157728, a nearby star 1.5 times larger than the sun. The star is centered in both images, and its light has been mostly removed by an adaptive optics system and coronagraph belonging to Project 1640, which uses new technology on the Palomar Observatory’s 200-inch Hale telescope near San Diego, Calif., to spot planets. Credit: Project 1640

Looking directly at stars is a bad way to find planets orbiting faraway suns but using a new technique, scientists can now sift the starlight to find new exoplanets millions of times dimmer than their parent stars.

“We are blinded by this starlight,” says Ben R. Oppenheimer, a curator in the American Museum of Natural History’s Department of Astrophysics and principal investigator for Project 1640. “Once we can actually see these exoplanets, we can determine the colors they emit, the chemical compositions of their atmospheres, and even the physical characteristics of their surfaces. Ultimately, direct measurements, when conducted from space, can be used to better understand the origin of Earth and to look for signs of life in other worlds.”

Using indirect detection methods, astronomers have found hundreds of planets orbiting other stars. The light stars emit, however, is tens of millions to billions of times brighter than the light reflected by planets.

Project 1640 is an advanced telescope imaging system, made up of the world’s most advanced adaptive optics system, instruments and software. The project operates at the 200-inch Hale Telescope at California’s Palomar Observatory. Engineers at the American Museum of Natural History, California Institute of Technology, and NASA’s Jet Propulsion Laboratory worked more than six years developing the new system.

Earth’s atmosphere wreaks havoc with starlight. The heating and cooling of the atmosphere produces turbulence that creates a twinkling effect on the point-like light from a star. Optics within a telescope also warp light. The instruments that make up Project 1640 manipulate starlight by deforming a mirror more than 7 million times a second to counteract the twinkling. This produces a crystal clear infrared image of the star with a precision smaller than one nanometer; about 100 times smaller than a typical bacteria.

“Imaging planets directly is supremely challenging,” said Charles Beichman, executive director of the NASA ExoPlanet Science Institute at the California Institute of Technology. “Imagine trying to see a firefly whirling around a searchlight more than a thousand miles away.”

A coronagraph, built by the American Museum of Natural History, optically dims the star leaving other celestial objects in the field of view. Other instruments help create an “artificial eclipse” inside Project 1640. Only about half a percent of the original light remains in the form of a speckled background. These speckles can still be hundreds of times brighter than the dim planets. The instruments control the light from the speckles to further dim their brightness. What the instrument creates is a dark hole where the star had been while leaving the light reflected from any planets. Coordination of the system is extremely important, say the researchers. Even the smallest light leak would drown out the incredibly faint light from planets orbiting a star.

For now Project 1640, the world’s most advanced and highest contrast imaging system, is focusing on bright stars relatively close to Earth; about 200 light-years away. Their three-year survey includes plans to image hundreds of young stars. The planets they may find are likely to be very large, Jupiter-sized bodies.

“The more we learn about them, the more we realize how vastly different planetary systems can be from our own,” said Jet Propulsion Laboratory astronomer Gautam Vasisht. “All indications point to a tremendous diversity of planetary systems, far beyond what was imagined just 10 years ago. We are on the verge of an incredibly rich new field.”

Read more about Project 1640: http://research.amnh.org/astrophysics/research/project1640

Image Caption: Two images of HD 157728, a nearby star 1.5 times larger than the Sun. The star is centered in both images, and its light has been mostly removed by the adaptive optics system and coronagraph. The remaining starlight leaves a speckled background against which fainter objects cannot be seen. On the left, the image was made without the ultra-precise starlight control that Project 1640 is capable of. On the right, the wavefront sensor was active, and a darker square hole formed in the residual starlight, allowing objects up to 10 million times fainter than the star to be seen. Images were taken on June 14, 2012 with Project 1640 on the Palomar Observatory’s 200-inch Hale telescope. (Courtesy of Project 1640)

Life and Death in a Tangled Web of Space

The Vela-C molecular cloud region as observed in far-infrared wavelengths. Credit: CNRS/INSU - Univ. Paris Diderot, France

In a star-making nebula awash in a tangled nest of gas and glowing filaments, scientists have uncovered an interesting, previously unseen interplay between gravity and turbulence that affects the formation of stars.

This image, taken by the European Space Agency’s Herschel Space Observatory, shows the highly detailed structure of cool wispy filaments of the Vela C molecular cloud. Located just 2,300 light-years from Earth, Vela-C is a vast star-making complex of gas and dust. And within this glowing cloud, both high-mass stars and smaller Sun-like stars form through very different processes.

Gravitational attraction pulls gas and dust together to form massive clumps of matter in glowing ridges. According to scientists studying the image, the most massive and brightest stars will form within these clumps. Random motion and turbulence throughout the cloud appear to create the fine nest-like filaments. It’s within these areas that smaller stars will form. Tiny, white specks fleck the image. These white dots, more abundant in the ridge-like filaments, are pre-stellar cores; compact clumps of gas and dust that might ignite into new stars.

Vela-C’s proximity to Earth makes it an ideal laboratory to study the birth of different kinds of stars. The nebula may also make it a perfect study of supernovae. The blue areas in the image contain expanding pockets of hot gas energized by the strong solar wind and ultraviolet radiation of young and massive stars. Compared to our Sun’s expected 10 billion year life-span, these massive stars burn through their supply of nuclear fuel within just a few million years. At the end of their lives, these stars will explode in dazzling supernovae.

The Herschel Telescope, launched in 2009, explores the Universe in the far infrared. While interstellar dust is cold, it shines brightly against the even colder surrounding space. The longest wavelengths of light show up as the red filaments in this image. Shorter, signifying hotter, wavelengths of light show up as yellow, green and blue.

Image Caption: The Vela-C molecular cloud region observed in far-infrared wavelengths. Credit: ESA/PACS/SPIRE/Tracey Hill & Frédérique Motte, Laboratoire AIM Paris-Saclay, CEA/Irfu – CNRS/INSU – Univ. Paris Diderot, France

Remastering a Cosmic Cat Print

Cat's Paw Nebula. Credit: ESO/R. Gendler & R.M. Hannahoe

Glowing red against a backdrop of stars, amateur astronomers have remastered one of the sky’s most distinctive nebulae, the Cat’s Paw Nebula.

In a stunning combination of data from amateur and professional telescopes, Robert Gendler and Ryan M. Hannahoe mixed their 60 hours of exposures of the nebula on a 0.4-meter telescope with existing images from the 2.2-meter MPG/ESO telescope at the La Silla Observatory in Chile. (See the original image.)

The result is nothing short of beautiful (zoom into all its nebular grandeur at StarryCritters.com). The Cat’s Paw Nebula, also known as NGC 6334, Gum 64 and the Bear Claw Nebula, is found about 5,500 light-years from Earth toward the constellation Scorpius, the Scorpion. The nebula is one of the most active star-forming regions in the Milky Way Galaxy, spanning about 50 light-years, and contains thousands of new stars although most are hidden in the dense clouds of gas and dust. Blistering ultraviolet radiation from these stars excites hydrogen atoms within the star cloud causing it to glow with a characteristic red hue. English astronomer John Herschel first described the nebula in 1837 while observing from the Cape of Good Hope in South Africa.

Anyone using Adobe Photoshop might be familiar with the process used. By combining the luminance, or brightness, of the ESO image with color information from the pair’s long exposures, Gendler and Hannahoe were able to bring out more vibrant color, such as the faint blue nebulosity near the center of the nebula and surrounding some of the brighter stars. The image from the ESO telescope adds finer details.

Does anyone else see the similarity between the arched shape in the middle of the nebula with the Federation insignia from the popular television series Star Trek?

Image Credit: ESO/R. Gendler & R.M. Hannahoe

Oldest Impact Crater on Earth Discovered in Greenland

Artistic expression of large meteorite impact

With shifting continents, rain, and wind, finding traces of ancient impact craters on Earth has been, literally, astronomically low. Now, an international team of scientists say they have found a massive impact crater in Greenland a billion years older than other known asteroid impact on Earth.

Scientists found the remains of the giant 100-kilometer (62 mile) wide crater near the Maniitsoq region of West Greenland and they believe it’s three billion years old. The largest and previously oldest known crater is the 300 kilometer-wide Vredefort crater in South Africa. Tipped on its side, the edges of the Maniitsoq crater would extend from the surface of the Earth to the edge of space.


“This single discovery means that we can study the effects of cratering on the Earth nearly a billion years further back in time than was possible before,” according to Dr. Iain McDonald of the School of Earth and Ocean Sciences at Cardiff University, who was part of the team.

Finding the crater wasn’t an easy task. Today, the Moon still shows marks of the massive bombardment that took place between three and four billion years ago. The early Earth, with its greater gravitational attraction, would have experienced even more collisions. But the land around Maniitsoq has been eroded over the eons to expose crust that originally was 25 kilometers (16 miles) below the surface. Effects of the immense shockwave produced on impact penetrated deep into the crust and remain visible.

Evidence at that depth had never been observed before, says McDonald. “The process was rather like a Sherlock Holmes story,” said McDonald. “We eliminated the impossible in terms of any conventional terrestrial processes, and were left with a giant impact as the only explanation for all of the facts.”

Only about 180 impact craters have been discovered on Earth. Around 30 percent of them contain important natural resources, including nickel, gold, oil and natural gas. It was during an exploration of natural resources that evidence for the crater was discovered. “It has taken us nearly three years to convince our peers in the scientific community,” said McDonald. “But the mining industry was far more receptive. A Canadian exploration company has been using the impact model to explore for deposits of nickel and platinum metals at Maniitsoq since the autumn of 2011.”

The international team, led by Adam Garde, a senior research scientist at the Geological Survey of Denmark and Greenland, or GEUS, contains members from Cardiff, Lund University in Sweden, and the Institute of Planetary Science in Moscow. Their work was recently published in the jounal Earth and Planetary Science Letters.

Image caption: An artistic expression of how a large meteorite impact into the sea might have looked in the first second of the impacting. We do not know if the area that was hit was actually covered by water or if there was just a sea nearby. Source: Carsten Egestal Thuesen, GEUS

Map caption: Black circle on map shows the location of the meteorite impact structure near the town Maniitsoq in Greenland.

Read more about the Maniitsoq structure.

Galactic Gong – Milky Way Struck and Still Ringing After 100 Million Years

Small Magellanic Cloud

When galaxies collide, stars are thrown from orbits, spiral arms are stretched and twisted, and now scientists say galaxies ring like a bell long after the cosmic crash.

A team of astronomers from the United States and Canada say they have heard echoes of that ringing, possible evidence of a galactic encounter 100 million years ago when a small satellite galaxy or dark matter object passed through the Milky Way Galaxy; close to our position in the galaxy, as if a rock were thrown into a still pond causing the stars to bounce up and down on the waves. Their results were published in the Astrophysical Journal Letters.

“We have found evidence that our Milky Way had an encounter with a small galaxy or massive dark matter structure perhaps as recently as 100 million years ago,” said Larry Widrow, professor at Queen’s University in Canada. “We clearly observe unexpected differences in the Milky Way’s stellar distribution above and below the Galaxy’s midplane that have the appearance of a vertical wave — something that nobody has seen before.”

Astronomers took observations from about 300,000 nearby stars in the Sloan Digital Sky Survey. Stars move up and down at 20-30 kilometers per second while see-sawing around the galaxy at 220 kilometers per second. By comparison, the International Space Station putters around Earth at 7.71 kilometers per second; Voyager 1, the fastest man-made object, currently is leaving the solar system at about 17.46 kilometers per second. Widrow and colleagues at the University of Kentucky, The University of Chicago and Fermi National Accelerator Laboratory found that the positions of nearby stars is not quite as regular as previously thought. The team noticed a small but statistically significant difference in the distribution of stars above and below the midplane of the Milky Way.

“Our part of the Milky Way is ringing like a bell,” said Brian Yanny, of the Department of Energy’s Fermilab. “But we have not been able to identify the celestial object that passed through the Milky Way. It could have been one of the small satellite galaxies that move around the center of our galaxy, or an invisible structure such as a dark matter halo.”

Susan Gardner, professor of physics at the University of Kentucky added, “The perturbation need not have been a single isolated event in the past, and it may even be ongoing. Additional observations may well clarify its origin.”

Other possibilities considered for the variations were the effect of interstellar dust or simply the way the stars were selected in the survey. But as those events failed to explain fully the observations, the astronomers began to explore possible recent events in the history of the galaxy.

More than 20 visible satellite galaxies circle the Milky Way. Invisible satellites made up of dark matter, hypothetical matter that cannot be seen but is thought to make up a majority of the mass of the Universe, might also orbit our galaxy. Scientists believe that most of the mass orbiting the galaxy is in the form of dark matter. Using computer simulations to explore the effects of a small galaxy or dark matter structure passing through the disk of the Milky Way, the scientists developed a clearer picture of the see-saw effects they were seeing.

In terms of the nine-billion lifetime of the Milky Way Galaxy, the effects are short-lived. This part of the galaxy has been “ringing” for 100 million years and will continue for 100 million years more as the up-and-down motion dissipates, say the astronomers – unless we are hit again.

Image caption: The Small Magellanic Cloud is one of 20 visible satellite galaxies that orbit the Milky Way Galaxy. Astronomers report that a smaller counterpart or dark matter object passed through the Milky Way near our position about 100 million years ago.

Build a NASA Satellite, Study the Universe Online

Thanks to a new online game from NASA, everyone can be an engineer or astronomer and build a satellite to uncover planets orbiting distant stars, unravel the secrets of a black hole, or tease out the faint glow of the early Universe.

NASA Goddard Space Flight Center in Greenbelt, Maryland, launched the new game, called “Build it Yourself: Satellite!” The Flash-based game, a learning tool for students and adults, is just a click away at http://www.jwst.nasa.gov/build.html.

“It’s fun to play and users will learn something about satellite instrumentation and optics, and how they are used to make scientific discoveries, as well about a large range of different existing astronomical missions,” said Maggie Masetti, NASA webmaster who authored and created the game. Artwork for the game is by Susan Lin and programmed by Kent deVillafranca.

Players begin by choosing what science their satellite will study; whether it’s black holes, star formation, early Universe, galaxies, or explanets. Then online engineers will decide the wavelengths – optical, infrared, ultraviolet – that their spacecraft will study. Finally, a choice must be made on the instruments and optics the mission will carry. Along the way, information bubbles explain each of the pieces you choose. After “launch,” the player sees what the satellite might look like and learn what real mission has data similar to what they created. Along the way, players learn about the different instruments added to various space missions and see the cosmic discoveries they might make.

Players can create a wide-range of satellites from small X-ray telescopes like NASA’s Rossi X-ray Timing Explorer, launched in 1995, to large orbiting telescopes like the NASA/ESA Hubble Space Telescope. Play it right, putting the right pieces together, and you can assemble a satellite superior to NASA’s huge, multi-mirrored James Webb Space Telescope, the original inspiration for the game. The Webb telescope currently is being built and will launch in 2018. With the Webb, scientists will be able to study the Universe nearly to the time of the Big Bang with infrared instruments.

Play the game at: http://www.jwst.nasa.gov/build.html

Find out more information about the James Webb Space Telescope here

Image caption: Front page of the Webb telescope on-line game, “Build It Yourself: Satellite!” Credit: NASA, M.Masetti

Daylight Fireball Dazzles Colorado, Grounds Fire Tankers

Fireball Meteor

A dazzling daytime fireball zipped across New Mexico and Colorado yesterday creating a stir among law enforcement agencies, news organizations, radio stations and briefly grounded air tankers fighting wildfires west of Colorado Springs.

According to the Denver Post, Pueblo air-dispatch received reports of “balls of fire or something in the air.” As a precaution, officials grounded flights to ensure no aircraft were hit. Flights resumed 90 minutes later.

The event occurred between 12:35 and 12:40 MDT Wednesday afternoon. Witnesses say the fireball lasted about 3 seconds about 45 degrees above the ground, heading from the north to the south and ending near the horizon, with a tail color ranging from bright white to yellow and red. Some of the nearly 20 reports received by the American Meteor Society report that the brightness of the fireball was brighter than a full moon; some reporting it brighter than the Sun.

A fireball is a meteor that is larger and brighter than normal. Although typically visible after sunset, dramatic fireballs have been recorded during the daytime, such as the April 22, 2012 bright daytime meteor that was seen over California in the US. Usually meteors are smaller than a pebble and move very fast. As the object encounters increased friction from the air in the upper atmosphere, it begins to get hot and glow. Most meteors burn up before hitting the ground. But some survive to be picked up and put in museums. Scientists estimate that nearly 100 tons of space dust lands on Earth every day. Most of it lands in the ocean.

The North American Aerospace Defense Command (NORAD) based at Peterson Air Force Base near Colorado Springs told the Denver Post they were not tracking any man-made objects in the area.

The Denver Museum of Nature and Science has meteor cameras stationed around the state. Unfortunately, they are turned off during the day and no video or pictures have surfaced.

Astronomers and meteor/meteorite enthusiasts will certainly be interested in seeing any pictures or videos of the event, and so are we! If saw the event, or happened to capture it on a camera or surveillance video, you can send it to us or post it on our Flickr page.

Lead image caption: A Perseid fireball meteor. Credit: Pierre Martin of Arnprior, Ontario, Canada.

Early Black Holes were Grazers Rather than Glutonous Eaters

Faint quasars powered by black holes. Image credit NASA/ESA/Yale

Black holes powering distant quasars in the early Universe grazed on patches of gas or passing galaxies rather than glutting themselves in dramatic collisions according to new observations from NASA’s Spitzer and Hubble space telescopes.

A black hole doesn’t need much gas to satisfy its hunger and turn into a quasar, says study leader Kevin Schawinski of Yale “There’s more than enough gas within a few light-years from the center of our Milky Way to turn it into a quasar,” Schawinski explained. “It just doesn’t happen. But it could happen if one of those small clouds of gas ran into the black hole. Random motions and stirrings inside the galaxy would channel gas into the black hole. Ten billion years ago, those random motions were more common and there was more gas to go around. Small galaxies also were more abundant and were swallowed up by larger galaxies.”

Quasars are distant and brilliant galactic powerhouses. These far-off objects are powered by black holes that glut themselves on captured material; this in turn heats the matter to millions of degrees making it super luminous. The brightest quasars reside in galaxies pushed and pulled by mergers and interactions with other galaxies leaving a lot of material to be gobbled up by the super-massive black holes residing in the galactic cores.

Schawinski and his team studied 30 quasars with NASA’s orbiting telescopes Hubble and Spitzer. These quasars, glowing extremely bright in the infrared images (a telltale sign that resident black holes are actively scooping up gas and dust into their gravitational whirlpool) formed during a time of peak black-hole growth between eight and twelve billion years ago. They found 26 of the host galaxies, all about the size of our own Milky Way Galaxy, showed no signs of collisions, such as smashed arms, distorted shapes or long tidal tails. Only one galaxy in the study showed evidence of an interaction. This finding supports evidence that the creation of the most massive black holes in the early Universe was fueled not by dramatic bursts of major mergers but by smaller, long-term events.

“Quasars that are products of galaxy collisions are very bright,” Schawinski said. “The objects we looked at in this study are the more typical quasars. They’re a lot less luminous. The brilliant quasars born of galaxy mergers get all the attention because they are so bright and their host galaxies are so messed up. But the typical bread-and-butter quasars are actually where most of the black-hole growth is happening. They are the norm, and they don’t need the drama of a collision to shine.

“I think it’s a combination of processes, such as random stirring of gas, supernovae blasts, swallowing of small bodies, and streams of gas and stars feeding material into the nucleus,” Schawinski said.

Unfortunately, the process powering the quasars and their black holes lies below the detection of Hubble making them prime targets for the upcoming James Webb Space Telescope, a large infrared orbiting observatory scheduled for launch in 2018.

You can learn more about the images here.

Image caption: These galaxies have so much dust enshrouding them that the brilliant light from their quasars cannot be seen in these images from the NASA/ESA Hubble Space Telescope.

Huge Wildfires Burn on Opposite Sides of the Planet

The latest views of Earth from NASA’s Aqua and Terra satellites are looking a bit hazy from wildfires burning in wilderness areas of the United States and Siberia.

The above image acquired July 18 from the Moderate Resolution Imaging Spectroradiometer, or MODIS, aboard the Terra satellite, shows a whopping 198 wildfires burning across Siberia. You can view more of this huge fire at NASA’s Earth Observatory website. The fires have charred an area of more than 83 square kilometers. Some of the fires were started by people who lost control of agricultural fires but some fires were started by lightning.

High Park Fire from NASA's Aqua MODIS
Another NASA earth-observing satellite, Aqua, has taken dramatic images of the High Park Fire just west of Fort Collins, Colorado and the Whitewater-Baldy Complex Fire in southwestern New Mexico. The High Park Fire has grown to more than 235 square kilometers, burning 180 structures and leading to the death of one person. It has become one of the most destructive and largest fires in Colorado history. Thankfully, the

Besides measuring the smoke plume and fire extent, much can be learned using satellite images of wildfires. Types of vegetation can affect the type and color of smoke emitted by the wildfire. Grassland fires tend to burn quickly and give off carbon-rich black smoke. Forest fires where moisture is higher give off thicker smoke; a combination of organic rich ash and water vapor, that ranges in color from brown to bright white.

Pyrocumulus cloud from High Park Fire, ColoradoOn the plus side for weather buffs, each of the fires have produced rare pyrocumulus, or fire clouds. Wildfires and volcanos can produce these dramatic clouds as intense heating causes the air to rise. As the rising air cools, water vapor in the ash cloud condenses just like a normal cloud. The ash particles provide nuclei for water to condense. Sometimes this moisture will fall back on the fire as rain. Dave Lipson, a meteorologist with the National Oceanic and Atmospheric Administration told the Denver Post that calm and clear weather along Colorado’s Front Range made the towering pyrocumulus cloud look especially menacing Tuesday. Tuesday afternoon, the lone fire cloud could be seen from 40 miles away from Denver.

Lead image caption: NASA image courtesy Jeff Schmaltz, LANCE MODIS Rapid Response. Instrument: Terra – MODIS

Second image caption: High Park Fire, Colorado from NASA’s Aqua MODIS

Third image caption: Looking north near Boulder, Colorado at the pyrocumulus cloud produced from the High Park Fire. Photo: John Williams