Astronaut Chris Cassidy getting strapped into the shuttle. Credit: NASA
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An historic milestone will be reached during the STS-127 space shuttle mission to the International Space Station, which will hopefully launch on Wednesday. The crew will include the 500th person ever to fly in space. Since there are four rookie astronauts on the mission, it’s a bit of a coin toss as to who is actually the 500th, but seemingly the crew has agreed that former naval commander Chris Cassidy, 39, who has led combat missions in Afghanistan, will take the honor.
A few notables of the 499 who have gone before, below, and a quick report that things look good so far for Endeavour’s second launch attempt. NASA is shooting for 5:40:52 a.m. Wednesday (9:40 GMT) on Wednesday June 17.
Workers on Kennedy Space Center's Launch Pad 39A prepare to remove the 7-inch quick disconnect and flight seal from the Ground Umbilical Carrier Plate, or GUCP, on space shuttle Endeavour's external fuel tank. Teams are removing the hardware to change out seals in the internal connection points. The GUCP is the overboard vent to the pad and the flare stack where the vented hydrogen is burned off. Credit: NASA
Click on image for a really huge version.
On Tuesday, engineers pulled a protective gantry away from the shuttle Endeavour and restarted the orbiter’s countdown Tuesday, setting the stage for launch. There are no technical problems of any significance and forecasters are predicting an 80 percent chance of good weather at launch time. You can watch NASA TV or follow Nancy on Twitter for updates.
Looming vertical structures, seen here for the first time and created by Saturn's moon Daphnis, rise above the planet's otherwise flat, thin disk of rings to cast long shadows in this Cassini image. Credit: CICLOPS.
Cassini has imaged towering vertical structures in the planet’s otherwise flat rings that come from the gravitational effects of a small nearby moon. This is the first time these structures have been seen. They reach up over one kilometer high, and are visible now as the sun nears “high noon” directly overhead at the planet’s equator, as Saturn approaches its equinox.
The search for ring material extending above and below Saturn’s ring plane has been a major goal of the imaging team during Cassini’s “Equinox Mission,” the two-year period containing the exact equinox. This novel illumination geometry, which occurs every half-Saturn-year, or about 15 Earth years, lowers the sun’s angle to the ring plane and causes out-of-plane structures to cast long shadows across the rings, making them easy to detect.
Images taken in recent weeks have demonstrated how small moons in very narrow gaps can have considerable and complex effects on the edges of their gaps, and that such moons can be smaller than previously believed. Looming vertical structures, seen here for the first time and created by Saturn's moon Daphnis, rise above the planet's otherwise flat, thin disk of rings to cast long shadows in this Cassini image. Credit: CICLOPS
The 8-kilometer-wide (5-mile) moon Daphnis orbits within the 42-kilometer-wide (26-mile) Keeler Gap in Saturn’s outer A ring, and its gravitational pull perturbs the orbits of the particles forming the gap’s edges. Earlier images have shown “waves” in the rings from Daphnis eccentric orbit.
But new images show the shadows of the vertical waves created by Daphnis cast onto the nearby ring. These characteristics match what was predicted by scientists.
Scientists have estimated, from the lengths of the shadows, wave heights that reach enormous distances above Saturn’s ring plane – as large as 1.5 kilometers (1 mile) — making these waves twice as high as previously known vertical ring structures, and as much as 150 times as high as the rings are thick. The main rings — named A, B and C — are only about 10 meters (30 feet) thick.
“We thought that this vertical structure was pretty neat when we first saw it in our simulations,” said John Weiss, lead author of a paper reporting on these images. “But it’s a million times cooler to have your theory supported by such gorgeous images. It makes you suspect you might be doing something right.”
Click here to watch a movie of the vertical structures and waves in motion.
Also presented in the paper is a refinement to a theory used since the Voyager missions of the 1980s to infer the mass of gap-embedded moons based on how much the moons affect the surrounding ring material. The authors conclude that an embedded moon in a very narrow gap can have a smaller mass than that inferred by earlier techniques. One of the prime future goals of the imaging team is to scour the remaining gaps and divisions within the rings to search for the moons expected to be there. “It is one of those questions that have been nagging us since getting into orbit: ‘Why haven’t we yet seen a moon in every gap?’” said Carolyn Porco, lead for the Cassini imaging team. “We now think they may actually be there, only a lot smaller than we expected.”
The heliosphere is often described as a kind of bubble that contains our solar system. This magnetic sphere, which extends beyond Pluto, is caused by the Sun’s solar winds. These winds spread out from the Sun at around 400 km/s until they hit what is known as interstellar space, which is also called local interstellar medium (LISM) or interstellar gas. Interstellar space is the space in galaxies that is unoccupied by either stars or planets.
When the solar winds hit local interstellar medium, a kind of bubble forms that prevents certain material from getting in. Thus, the heliosphere acts as a kind of shield that protects our solar system from cosmic rays, which are dangerous interstellar particles. The interaction between interstellar gas and solar winds depends on the pressure of the solar winds and properties of interstellar space, such as pressure, density, and qualities of the magnetic field. Astronomers believe that other solar systems have their own heliospheres caused by different stars.
There are several different parts of the heliosphere. The heliopause is the boundary between the heliosphere and the LISM. When solar winds approach this blurred region, they slow abruptly causing a shock wave to form known as the solar wind termination shock. The action is similar to slamming down on the brakes in a car, causing people and objects in the car to fly forward. This shock wave actually causes the particles to accelerate, aiding in the formation of the heliosphere. After it has slowed down, the winds of interstellar space act on the solar winds causing them to curve forming what has been described as a comet-like tail to the Sun. This tail, which has been examined by NASA’s probes Voyager 1 and Voyager2, is called the heliosheath. The termination shock is from around 75 to 90 astronomical units (AU) from our Sun, and at its closest point, the heliosheath is approximately 80 to 100 AU from the Sun.
Astronomers monitoring the Sun have noticed that solar winds have decreased to all-time lows. This affects the heliosphere, which in turn can affect Earth and other planets in the solar system. With solar winds lessening, astronomers fear that the strength of the heliosphere will also decrease, leaving our solar system vulnerable to dangerous cosmic rays. Because solar winds are cyclical, some scientists believe that instead of permanently decreasing, the solar winds are merely experiencing a lengthy low period.
Philipp Heck with the Allende Meteorite. Credit: Dan Dry
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Maybe we’re not as old as we think (or feel?). The interstellar stuff that was integrated into the planets and life on Earth has younger cosmic roots than theories predict, according to the University of Chicago scholar Philipp Heck and his international team of colleagues.
Heck’s team analyzed 22 interstellar grains from the Murchison meteorite. Dying sun-like stars flung the Murchison grains into space more than 4.5 billion years ago, before the birth of the solar system. Scientists know the grains formed outside the solar system because of their exotic composition.
“The concentration of neon, produced during cosmic-ray irradiation, allows us to determine the time a grain has spent in interstellar space,” Heck said. His team determined that 17 of the grains spent somewhere between three million and 200 million years in interstellar space, far less than the theoretical estimates of approximately 500 million years. Only three grains met interstellar duration expectations (two grains yielded no reliable age).
“The knowledge of this lifetime is essential for an improved understanding of interstellar processes, and to better contain the timing of formation processes of the solar system,” Heck said. A period of intense star formation that preceded the sun’s birth may have produced large quantities of dust, thus accounting for the timing discrepancy, according to the research team.
And if you’re interested in looking back, here’s an archive to all the past Carnivals of Space. If you’ve got a space-related blog, you should really join the carnival. Just email an entry to [email protected], and the next host will link to it. It will help get awareness out there about your writing, help you meet others in the space community – and community is what blogging is all about. And if you really want to help out, let Fraser know if you can be a host, and he’ll schedule you into the calendar.
Finally, if you run a space-related blog, please post a link to the Carnival of Space. Help us get the word out.
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Most scientists predict that in about a billion years, the sun’s ever-increasing radiation will have scorched the Earth beyond habitability. The breathable air will be toast, the carbon dioxide that serves as food for plant life will disappear, the oceans will evaporate; and all living things will disappear. Or maybe not. A group of researchers from Caltech have studied a mechanism which would cause any planet with living organisms to remain habitable longer than originally thought, perhaps doubling the lifespan. This sounds like good news for future inhabitants of Earth, but also, this mechanism could increase the chance that life elsewhere in the Universe might have the time to progress to advanced levels.
The researchers say that atmospheric pressure is a natural climate regulator for a terrestrial planet with a biosphere. Currently, and in the past, Earth has maintained its surface temperatures through the greenhouse effect. There used to be greater amounts of CO2 and other greenhouse gases in the atmosphere 1 billion years ago, which was a good thing. Otherwise, the Earth might have been a frozen ice cube. But as the sun’s luminosity and heat increased as it has aged, Earth has naturally coped by reducing the amount of greenhouse gases in the atmosphere, thus reducing the warming effect and making the surface of the planet comfortably habitable.
Opposite of what most scientists claim however, Caltech professor Joseph L. Kirschvink says that Earth may be nearing the point where there’s not enough carbon dioxide left to regulate temperatures using that same procedure. But not to fear, there’s another mechanism underway that may work even better to regulate temperatures on Earth, keeping our home planet comfortable for life even longer than anyone ever predicted. Atmospheric pressure: Credit: Hulu.com
In their paper, Kirschvink and his collaborators Caltech professor Yuk L. Yung, and graduate students King-Fai Li and Kaveh Pahlevan show that atmospheric pressure is a factor that adjusts the global temperature by broadening infrared absorption lines of greenhouse gases. Their model suggests that by simply reducing the atmospheric pressure, the lifespan of a biosphere can be extended at least 2.3 billion years into the future, more than doubling previous estimates.
The researchers use a “blanket” analogy to explain the mechanism. For greenhouse gases, carbon dioxide would be represented by the cotton fibers making up the blanket. “The cotton weave may have holes, which allow heat to leak out,” explains Li, the lead author of the paper.
“The size of the holes is controlled by pressure,” Yung says. “Squeeze the blanket,” by increasing the atmospheric pressure, “and the holes become smaller, so less heat can escape. With less pressure, the holes become larger, and more heat can escape,” he says, helping the planet to shed the extra heat generated by a more luminous sun.
The solution is to reduce substantially the total pressure of the atmosphere itself, by removing massive amounts of molecular nitrogen, the largely nonreactive gas that makes up about 78 percent of the atmosphere. This would regulate the surface temperatures and allow carbon dioxide to remain in the atmosphere, to support life.
This wouldn’t have to be done synthetically – it appears to happen normally. The biosphere itself takes nitrogen out of the air, because nitrogen is incorporated into the cells of organisms as they grow, and is buried with them when they die.
In fact, “this reduction of nitrogen is something that may already be happening,” says Pahlevan, and that has occurred over the course of Earth’s history. This suggests that Earth’s atmospheric pressure may be lower now than it was earlier in the planet’s history. A possible habitable world? Credit: NASA/JPL
Proof of this hypothesis may come from other research groups that are examining the gas bubbles formed in ancient lavas to determine past atmospheric pressure: the maximum size of a forming bubble is constrained by the amount of atmospheric pressure, with higher pressures producing smaller bubbles, and vice versa.
If true, the mechanism also would potentially occur on any extrasolar planet with an atmosphere and a biosphere.
“Hopefully, in the future we will not only detect earth-like planets around other stars but learn something about their atmospheres and the ambient pressures,” Pahlevan says. “And if it turns out that older planets tend to have thinner atmospheres, it would be an indication that this process has some universality.”
The researchers hope atmospheres of exoplanets can be studied to see if this is occurring on other worlds.
And if the duration of habitability could be longer on our own planet, this might have implications for finding intelligent life elsewhere in the Universe.
“It didn’t take very long to produce life on the planet, but it takes a very long time to develop advanced life,” says Yung. On Earth, this process took four billion years. “Adding an additional billion years gives us more time to develop, and more time to encounter advanced civilizations, whose own existence might be prolonged by this mechanism. It gives us a chance to meet.”
Pretty pictures of volcanoes are nice, but to really appreciate the power and fury of a volcano check out some volcano videos.
Here’s a video of the Kilauea volcano in Hawaii. The lava pouring out of Kilauea flows very easily, so it can travel for long distances and create lava fountains and lakes.
Here’s a preview of National Geographic’s documentary video, Inside a Volcano. You can see different kinds of volcanoes erupting. Very spectacular.
Also from National Geographic, this is their volcano 101 video. It shows you the basics of how volcanoes work, how they form, and the different kinds of eruptions.
Here’s a video of an underwater volcano presented by Wired.com. You can see what happens when hot ash and lava meets cold sea water. Did you know that 75% of all volcanoes are underwater volcanoes, and most of those are never detected.
Finally, here’s a video from the Discovery Channel with links and video of the 5 best volcano web cams. It’s a great tour through some of the coolest volcano webcams on the planet.
We have written many article about volcanoes for Universe Today. Here’s an article about
An innovative new sky survey called the Palomar Transient Factory (PTF) will use a 48-inch telescope together with the U.S. Department of Energy’s (DOE’s) National Energy Research Scientific Computing Center (NERSC) to discover relatively rare and fleeting cosmic events like supernovae and gamma ray bursts. The survery is already in progress, and during the commissioning phase alone, the survey has already uncovered more than 40 supernovae. Astronomers expect to discover thousands more each year.
“This survey is a trail blazer in many ways – it is the first project dedicated solely to finding transient events, and as part of this mission we’ve worked with NERSC to develop an automated system that will sift through terabytes of astronomical data every night to find interesting events, and have secured time on some of the world’s most powerful ground-based telescopes to conduct immediate follow up observations as events are identified,” says Shrinivas Kulkarni, a professor of astronomy and planetary science at the California Institute of Technology (Caltech), and Director of Caltech Optical Observatories. He is also principle investigator of the PTF survey.
“This truly novel survey combines the power of a wide-field telescope, a high-resolution camera, and high-performance network and computing, as well as the ability to conduct rapid follow-up observations with telescopes around the globe for the first time,” says Peter Nugent, a computational staff scientist in Berkeley Lab’s Computational Research Division (CRD) and the NERSC Analytics Group. Nugent is also the Real-time Transient Detection Lead for the PTF project.
Every night the PTF camera – a 100-megapixel machine mounted on the 48-inch Samuel Oschin Telescope at Palomar Observatory in Southern California – will automatically snap pictures of the sky, then send those images to NERSC for archiving via a high-speed network provided by DOE’s Energy Sciences Network (ESnet) and the National Science Foundation’s (NSF’s) High Performance Wireless Research and Education Network (HPWREN).
At NERSC, computers running machine-learning algorithms in the Real-time Transient Detection pipeline scour the PTF observations for “transient” sources, cosmic objects that change in brightness or position, by comparing the new observations with all of the data collected from previous nights. Within minutes after interesting event is discovered, machines at NERSC will send its coordinates to Palomar’s 60-inch telescope for follow up observations.
“We are currently uncovering one event every 12 minutes. This project will be keeping the astronomical community busy for quite a while,” says Kulkarni.
The primary target of the sky survey are Type Ia and Type II supernovae.
Because they are relatively uniform in brightness, Type Ia supernovae act as cosmic lighthouses, helping astronomers judge the distance scale of the universe. Many astronomers participating in the PTF survey are specifically searching for these phenomena.
And Type II supernovae, the kind cause by the detonation of a massive star that’s run out of fuel, blast heavy elements into interstellar space, where they eventually form new stars and planets.
“These tools are extremely valuable because they not only help us identify supernova, they uncover them while the star is in the act of exploding,” says Robert Quimby of Caltech, who is the software lead for the PTF program. “This gives us valuable information about how cosmic dust is spread across the universe.”
“It is very exciting to find so many supernovae, so early in the project. It’s like we’ve just turned on the spigot and are now waiting for the fire hose to blast,” says Quimby.
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Epsilon Aurigae is a mystery. This variable star changes in brightness over time, and is thought to be an eclipsing binary. Some things about the way that this star fades and then regains it brightness are still not fully understood by astronomers, even after over 175 years of study. But now, you can help. The next eclipse of this star is predicted to begin in August 2009. Citizen Sky is a citizen science project providing you with a chance to do real scientific research to help solve the mystery.
Epsilon Aurigae is a very bright star — a third-magnitude F-type supergiant star — located in the constellation Auriga, the charioteer. This star is bright enough to be seen with the unaided eye even in the most light-polluted cities, and it is visible every autumn, winter, and spring. Because of its brightness, it can be observed by almost anyone regardless of background, training, or equipment. All you need are a good pair of eyes and know where to look. Epsilon Aurigae model. Credit: NOAO, AURA, & NSF.
This star has two-year-long eclipse that occurs every 27 years. But no one knows what eclipses the star, and the eclipse is very unusual. One of the possible models for epsilon Aurigae is that a large opaque disk seen nearly edge-on eclipses the primary star. The center of the disk might be partly transparent, due to the presence of one or more massive main-sequence stars. Because the disk is seen nearly edge-on to our line of sight, the supergiant star isn’t completely obscured even at the eclipse minimum.
Citizen Sky has put together materials guide you through the process of how to observe epsilon Aurigae, how to send in your observations, and then how to see your results, analyze them, and even publish them in a scientific journal! No previous experience is required. Citizen Sky hopes to involve thousands of people all over the world in real, active scientific research.
To learn more and get involved, visit Citizen Sky.
LRO on the launchpad. Credit: NASA
It’s a crowded dance floor and someone had to step aside. Because of Saturday’s launch delay for STS-127, the shuttle and the upcoming dual mission to the moon — the Lunar Reconnaissance Orbiter (LRO) and Crater Observation and Sensing Satellite (LCROSS) — were both vying to launch from Kennedy Space Center on the same day, which is not a possibility (usually there needs to be at least 48 hours between launches as the Air Force’s Eastern Range that monitors needs that amount of time to reconfigure the systems.) At a press conference today, NASA launch manager at KSC, Chuck Dovale announced LRO/LRCROSS will give up their originally schedule launch date of June 17 so that the shuttle can go. “We are relinquishing the June 17 date to the shuttle,” he said. “However, we will maintain June 18 as the earliest possible date for LRO/LCROSS. We will monitor the shuttle’s progress, and if they were to scrub the launch for any reason before midnight on the 16th, we can still maintain launch on the 18th.” But there’s a lot that has to go right for the optimum and hoped for launch schedules to happen. Continue reading “LRO/LCROSS Gives Up Launch Date for STS-127”
