Nearly 60 years ago, audiences thrilled to the destruction of the Earth in George Pal’s classic film, “When Worlds Collide.” The idea of a planetary smash-up is a staple of science fiction, but can it really happen?
Astronomers using NASA’s Spitzer Space Telescope think they’ve actually seen the aftermath of such a collision around another star.
The story unfolded as Dr. Casey Lisse and his team studied disks around young stars. Once planets have formed astronomers think there are a lot of left-over asteroids in the system. They occasionally slam together and produce dusty debris.
Spitzer’s Infrared Spectrograph was designed to detect the faint glow from this material. By spreading the light out into its component colors, astronomers can look for the spectral fingerprints of different minerals.
Our dusty star of interest is a faint speck known as HD 172555. It’s about 100 light years away and 12 million years old which, compared to our 4.5 billion year old Sun, is like a baby born a few days ago.
Studying its spectrum, Dr. Lisse and his colleagues realized they had found something very peculiar that they had not seen around other stars. Aside from the usual indicators of rocky rubble, Continue reading When Worlds Collide→
Best viewed in full screen 1080p. Using satellites, scientists have been tracking the movement of BP’s Deep Water Horizon oil slick as currents have pushed it closer and closer to the Gulf Coast. Now, scientists at the National Center for Atmospheric Research have used supercomputers to simulate its path in coming months as it moves up the Atlantic seaboard in major ocean currents.
Earth is constantly changing. Some changes are a natural part of the climate system, such as the seasonal expansion and contraction of the Arctic sea ice pack. The responsibility for other changes, such as the Antarctic ozone hole, falls squarely on humanity’s shoulders. NASA’s World of Change series documents how our planet’s land, oceans, atmosphere, and Sun are changing over time.
Mt. St. Helens
The devastation of the May 18, 1980, eruption of Mt. St. Helens and the gradual recovery of the surrounding landscape is documented in this series of satellite images from 1979–2009.
A massive irrigation project in the Kyzylkum Desert of central Asia has devastated the Aral Sea over the past 50 years. These images show the continued decline of the Southern Aral Sea in the past decade, as well as the first steps of recovery in the Northern Aral Sea in recent years.
To expand the possibilities for beachfront tourist development, Dubai, part of the United Arab Emirates, undertook a massive engineering project to create hundreds of artificial islands along its Persian Gulf coastline.
Check out the unusual visual style in this adaptation of the ground-breaking “Science on a Sphere” production, including depictions of Earth. From NASA and NOAA, with additional images from ESA Hubble.
We perceive light–we see it—but what we see and what it means are not the same. Without context, detail means nothing.
Oh, there are so many factors at play here: what wavelengths of light can we see, how well can our brains take what we see and turn it into something we understand?
And also, how do we compare ourselves to the thing we’re observing? What tools do we use to help us capture information? How do we turn light into data, data into pixels, pixels into meaning? Start with a planet.
For example, Earth. And as long as we’re at it, let’s tip the Earth to spin properly on its axis. Now, recall our original points of light. Our idea.
These are satellites in orbit. Satellites collect data as the Earth rotates beneath them.
Think of satellites as paint brushes working in reverse: instead of painting planets with light, satellites collect light reflected from planets below. With enough data we can paint a world.
NASA JPL scientists look for Earthly examples of the terrain features they’ve been seeing on Saturn’s moon Titan, including the dry landscapes of Death Valley, California. From NASA’s Jet Propulsion Laboratory.
Since we’re probably never going to get to the surface of Titan and be able to pick up the rocks and take samples of the liquid, we wanted to be able to understand a place that we can get to, and then draw conclusions about Titan.
We believe that geology is geology everywhere. So we’ve come to Death Valley, to Racetrack Playa. It’s a dry lake right now, but it’s a lake nonetheless; so we can look for similar pieces of evidence. The reason we do that is we can crawl around Death Valley and measure things. We could find out what’s happening and find out what causes that evidence to occur. And it’s just like a detective game from there on.
So whenever you have a high thing next to a low thing, you can be sure that something’s going to happen. Nature likes to even itself out. On Ontario Lacus, we have high things right next to low things. So the rainfall is going to move the material Continue reading Earth & Titan→
Take a DEEP BREATH before watching this ESOCast mashup with Dr. J. The Sun is setting behind Cerro Paranal in the Chilean Atacama desert. While astronomers get ready to observe with ESO’s Very Large Telescope, Nature prepares for her own grand display. As night falls over the desert, the southern sky reveals its nocturnal beauty, leaving the spectator in silent amazement. Some people, however, don’t just stare at the spectacle. With great skill, they record these unique moments for everyone to see – they are the photographers of the night.
Anyone who has been up at night in a remote, high place such as at one of ESO’s observatories in Chile may have been lucky enough to experience the splendid view of the myriad stars shining brightly from the heavens. It is a both a dream and a challenge for a photographer to capture an image of this incredible view. Today we will focus on three ESO staff members, who, during their free time, produce outstanding astrophotography. By publishing their results on the internet they share their enthusiasm for the astonishing wonders of the southern skies with a wider audience.
While orbiting Saturn for the last six years, NASA’s Cassini spacecraft has kept a close eye on the collisions and disturbances in the gas giant’s rings. They provide the only nearby natural laboratory for scientists to see the processes that must have occurred in our early solar system, as planets and moons coalesced out of disks of debris.
New images from Cassini show icy particles in Saturn’s F ring clumping into giant snowballs as the moon Prometheus makes multiple swings by the ring. The gravitational pull of the moon sloshes ring material around, creating wake channels that trigger the formation of objects as large as 20 kilometers (12 miles) in diameter.
Saturn’s thin, kinky F ring was discovered by NASA’s Pioneer 11 spacecraft in 1979. Prometheus and Pandora, the small “shepherding” moons on either side of the F ring, were discovered a year later by NASA’s Voyager 1. In the years since, the F ring has rarely looked the same twice, and scientists have been watching the impish behavior of the two shepherding moons for clues.
A beautiful nugget from Spitzer’s “Hidden Universe.” Behind a dark veil of dust in the constellation Sagittarius, a lurking dragon has been revealed by the infrared eye of NASA’s Spitzer Space Telescope.
The red dots along its dark filaments are baby stars forming at a furious rate. The dark Dragon appears to fly away from M17, its brightly glowing neighbor known alternately as the Omega or Swan nebula. Oddly, astronomers have found that both the Dragon and the Swan are forming roughly the same numbers of stars.
If so, why should they look so different from one another? The answer may be that dragons, rather than ugly ducklings, grow up to become swans. While the Dragon is forming fairly large type B stars, only in the Swan do we find the very largest O stars. Their brilliant glare illuminates and disperses the dust, creating a nebula that is equally vivid in infrared and visible light.
The gas and dust clouds in this region appear to be passing through the Sagittarius spiral arm, a kind of gravitational traffic jam. Astronomers have long believed clouds will bunch up when they enter a spiral arm, triggering the gravitational collapse needed to form stars. Continue reading Lurking Dragon, Cosmic Swan→
The Fermi Gamma Ray Space Telescope picked up a whole new type of cosmic explosion: a ultra high-intensity explosion coming from the surface of a white dwarf star. The finding stunned observers and theorists alike because it overturns a long-standing notion that such novae explosions lack the power for such high-energy emissions.
In March, Fermi’s Large Area Telescope (LAT) detected gamma rays — the most energetic form of light — from the nova for 15 days. Scientists believe that the emission arose as a million-mile-per-hour shock wave raced from the site of the explosion. A nova is a sudden, short-lived brightening of an otherwise inconspicuous star. The outburst occurs when a white dwarf in a binary system erupts in an enormous thermonuclear explosion.
A giant 97-square mile slab of ice recently broke off from Greenland’s Petermann Glacier. Is this a sign that the climate is gradually changing? What does it mean in a global context? NASA scientists are training their satellites on these dynamic rivers of ice and factoring them into climate models designed to understand and predict where we’re going.