Satellite image of the oil leak in the Gulf of Mexico, as seen on June 19, 2010. Credit: MODIS Rapid Response Team.
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Here’s the latest satellite image of the BP oil leak in the Gulf of Mexico. The oil keeps spreading towards the northeast, and appears as a maze of silvery-gray ribbons in this image from the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite. The MODIS team said that the spot of black just north of the location of the oil well may be smoke; reports from the National Oceanic and Atmospheric Administration say that oil and gas continue to be captured and burned as part of the emergency response efforts.
Below is a video from reporter David Hammer from the Times-Picayune newspaper in New Orleans, Louisiana, who is covering the BP oil spill, explaining the latest developments as of June 21,2010. Apologies for the 15 second ad at the beginning, but Hammer provides a good overview of what has been happening.
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To date, SETI (Search for ExtraTerrestrial Intelligence) has focused on ETs who ‘phone home’ using the radio part of the electromagnetic spectrum, and even a very small region within that.
But what if ET’s phone doesn’t use radio waves? Sure the xkcd comic, is funny, but maybe it points to a deep flaw in our attempts to contact, or hear from, an ETI?
When Giuseppe Cocconi and Philip Morrison suggested the possibility of interstellar communication via electromagnetic waves in a 1959 paper in Nature, only radio was feasible, as we then had the ability to detect only artificial radio signals, if produced by ETIs with 1959 human technology. Since then we’ve developed the ability to detect a laser signal, brighter than the Sun (if only for a nanosecond) if it came from a source several light-years away … but lasers weren’t invented then.
What might ET’s equivalent of ants’ pheromones be?
Back in 1959 if you’d said that the Earth would, within a mere half century, started to go ‘radio quiet’, not many people would have taken you seriously. Yet that’s exactly what’s happened! Free to air (FTA) broadcasting, especially for TV, is being replaced by TV delivered over coaxial cable, optical fibers, or even the phone company’s twisted copper pairs. And where it’s continuing, as in satellite TV broadcasting, its power has dropped (today’s digital formats are more efficient than the old analog ones). Military radars, the brightest source of artificial radio waves by far, no longer broadcast in a single channel, but hop, rapidly, from frequency to frequency, to avoid jamming.
“Our improving technology is causing the Earth to become less visible,” says astronomer Frank Drake, SETI’s paterfamilias. “If we are the model for the universe, that is bad news.”
In the past half century SETI researchers have expanded the scope of their searches. Not only are far more radio channels being examined, but artificial signals in the optical are being sought too. How to decide which of the billions or trillions of possible radio channels to search? For example, the Allen Telescope Array will, when built, monitor a billion channels between 0.5 and 11 GHz – but that’s a trivial fraction of the entire radio waveband. Some ideas, however, seem cute; for example, the SETI Institute’s Gerald Harp has proposed searching at 4.462336275 gigahertz, in what’s called the PiHI range, because it’s the hydrogen atom’s emission frequency times pi. More seriously, Harvard University’s Paul Horowitz says optical SETI programs should really look at infrared frequencies “Stars are darker in the infrared and lasers are brighter and the smog goes away,” Horowitz says. Infrared allows astronomers to see into the galactic center, where dust scatters visible light.
There’s something rather ironic about SETI today; on the one hand, we recognize that our initial hopes were far too high, being based on overly simplistic assumptions; on the other, the tremendous progress in finding exoplanets has given us greater and greater certainty that Earth-like planets not only exist, but are, very likely, common. “All of astronomy has come to embrace this idea that there must be life out there,” says Harp.
So how to address the fact that we simply do not know what sorts of technologies a civilization like ours may have, a century or a millennium from now? After all, as Drake says “We are very conservative at SETI, we assume in our searches the existence of only things we ourselves have and know how to make.” Other scientists, and SETI enthusiasts, have proposed hunting in different electromagnetic realms, like gamma rays. Spacecraft that rely on nuclear fusion or antimatter-matter annihilation as a power source might produce such rays. But standard SETI strategy does not embrace such “speculative” scenarios.
SETI researchers, some say, should also contemplate what technologies supersmart aliens might possess and seek out the corresponding signals. In a 2008 arXiv paper, “Galactic Neutrino Communication“, John Learned of the University of Hawaii at Manoa suggested that ET could be sending beams of neutrinos Earth’s way. Energy requirements for such a beam make that scenario seem implausible, but not necessarily impossible. Detectors currently under construction, such as IceCube at the South Pole, could spot unexpected stray neutrinos. If a few with the same energy came from the same direction, astronomers would know something screwy was up.
In another paper, “The Cepheid Galactic Internet“, Learned suggests that ET could send a signal using a neutrino beam to deliver energy to a Cepheid variable. A Cepheid “blows up and comes crashing back down,” he says. “And the energy builds up and it blows again, like a geyser.” ET could leverage a Cepheid’s inherent instability by delivering a boost of energy that messes with the star’s schedule. Looking through existing data could reveal whether such meddling has occurred. “All that is needed is people analyzing for other reasons to do their analyses in another way,” Learned says.
Drake and most others agree that SETI’s approach should be multidirectional – let a thousand alien hunters bloom. The only ideas that don’t do anybody any good, Horowitz says, are the ones for which there is no conceivable way to look. “I’d like to keep an open mind,” he says, “but not so much that my brain falls out.”
Physicist Paul Davies of Arizona State University in Tempe, however, suggests that researchers don’t need to know what to look for. Find the fishy thing first, and then argue about its origin, he says.
As Davies has argued, maybe discovering ET does indeed depend on a thought revolution. Fifty years of signal-less searching suggests that the problem could lie not with the aliens among the stars, but with ourselves.
Maybe the sentient ants should not give up, just yet.
This is Saturn’s moon Dione, in crisp detail, against a hazy, ghostly Titan. Simply stunning.
The “wispy” terrain on Dione is visible, and on Titan are hints of atmospheric banding around Titan’s north pole. This view looks toward the Saturn-facing hemisphere of Dione (1123 kilometers, 698 miles across) and Titan (5150 kilometers, 3200 miles across), and was taken on April 10, 2010.
No images available yet from Cassini’s extremely close flyby of Titan over the weekend where it buzzed the hazy moon at an altitude of just 880 kilometers (547 miles) above the surface.
That is 70 kilometers (43 miles) lower than it has ever been at Titan before. The reason for attempting such a close pass is to try and establish if Titan has a magnetic field of its own. But the Cassini team went through hours and hours of calculations for this close flyby, as Titan’s atmosphere applies torque to objects flying through it, much the same way the flow of air would wiggle your hand around if you stuck it outside a moving car window. According to the Cassini website, when engineers calculated the most stable and safe angle for the spacecraft to fly, they found it was almost the same as the angle that would enable Cassini to point its high-gain antenna to Earth. So they cocked the spacecraft a fraction of a degree, enabling them to track the spacecraft in real-time during its closest approach. They set up the trajectory with thrusters firing throughout the flyby to maintain pointing automatically.
The images and data gathered should be amazing, as if everything went as planned, the flyby ended with the ultra violet imaging spectrograph (UVIS) instrument capturing a stellar occultation outbound from Titan. We’ll keep you posted!
Sunrise as seen by Doug Wheelock (Astro_Wheels on Twitter) from the ISS.
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Expedition 23 astronaut Soichi Noguchi took and shared so many amazing images during his 6-month stay on board the International Space Station, and I was a little worried that his return to Earth would result in a bit of a let-down in the space imaging department. I now see I had nothing to fear: Three new members of the Expedition 24 crew arrived at the ISS late last week and Doug Wheelock seems to have filled Soichi’s shoes (or socks, since they don’t wear shoes on the ISS) quite nicely. He posted two new images today on his Twitpic page that are nothing short of stunning. This image, above of an orbital sunrise provides a great look at the ISS bathed in “morning” light.
“A stunning sunrise aboard the International Space Station, as seen from the Russian MRM1 Module. We’re blessed with 16 sunrises each day!” Wheelock, a.k.a Astro_Wheels wrote.
See below for an aurora he captured over the South Pole.
An aurora seen over the South Pole, from the ISS. Credit: Doug Wheelock, NASA.
“A breath-taking masterpiece being painted in the sky over the South Pole. ‘The Southern Lights’…like brush strokes from the Master’s hand…” wrote Wheelock.
A recent image of a sunset taken from the ISS, is also incredibly beautiful. It wasn’t taken by Wheelock, but made NASA’s Earth Observatory’s website “Image of the Day” feature. Marvelous! The NASA page doesn’t say which astronaut took the image. Click the image for a larger, non-annotated view.
Sunset from the ISS shows the different layers of the atmosphere. Credit: NASA
And here’s a video I found of an orbital sunrise taken in 2006 on the STS-116 space shuttle mission.
Fifty years of eerie silence in the search for extra-terrestrial intelligence has prompted some rethinking about what we should be looking for.
After all, it’s unlikely that many civilizations would invest a lot of time and resources into broadcasting a Yoo-hoo, over here signal, so maybe we have to look for incidental signs of alien activity – anything from atmospheric pollution on an exoplanet to signs of stellar engineering undertaken by an alien civilization working to keep their aging star from turning into a red giant.
We know a spectroscopic analysis of Earth’s atmosphere will indicate free molecular oxygen – a tell tale sign of life. The presence of chlorofluorocarbons would also be highly suggestive of advanced industrial activity. We also know that atomic bomb tests in the fifties produced perturbations to the Van Allen belts that probably persisted for weeks after each blast.
These are planet level signs of a civilization still below the level of a Kardashev Type 1 civilization. We are at level 0.73 apparently. A civilization that has reached the Type 1 level is capable of harnessing all the power available upon a single planet – and might be one that inadvertently signals its presence after thoughtfully disposing of large quantities of nuclear waste in its star. To find them, we should be scanning A and F type stars for spectral signatures of technetium – or perhaps an overabundance of praseodymium and neodymium.
We might also look for signs of stellar engineering indicative of a civilization approaching the Kardashev Type 2 level, which is a civilization able to harness all the power of a star. Here, we might find an alien civilization in the process of star lifting, where an artificial equatorial ring of electric current creates a magnetic field sufficient to both increase and deflect all the star’s stellar wind into two narrow polar jets.
Left image - A proposed model for 'star lifting'. An artificial equatorial ring of electric current (RC) produces a magnetic field which enhances and directs the star's stellar wind though magnetic nozzles (MN) to produce two polar jets (J). Right image (Credit: SETI institute) - Artists impression of the completed Allen Telescope Array for future SETI observations. The lead image for this article is part of the current Allen Array prototype, comprising 42 of the proposed 350 dishes.
These jets could be used for power generation, but might also represent a way to prolong the life of an aging star. Indeed, this may become a vital strategy for us to prolong the solar system’s habitable zone at Earth’s orbit. In less than a billion years, Earth’s oceans are expected to evaporate due to the Sun’s steadily increasing luminosity, but some carefully managed star lifting to modify the Sun’s mass could extend this time limit significantly.
It’s also likely that Type 2 civilizations will play with Hertzsprung–Russell (H-R) parameters to keep their Sun from evolving onto the red giant branch of the H-R diagram – or otherwise from going supernova. Some well placed and appropriately shielded nuclear bombs might be sufficient to stir up stellar material that would delay a star’s shift to core helium fusion – or otherwise to core collapse.
It’s been hypothesized that mysterious giant blue straggler stars, which have not gone supernova like most stars of their type would, may have been tinkered with in this manner (some stress on the word hypothesized there).
As for detecting Type 3 civilizations… tricky. It’s speculated that they might build Dyson nets around supermassive black holes to harvest energy at a galactic level. But indications are that they then just use all that energy to go around annoying the starship captains of Type I civilizations. So, maybe we need to draw a line about who exactly we want to find out there.
An artist's rendering of a Kuiper Belt object. Image: NASA
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How do you study an extremely small planetary body in the dim outer reaches of our solar system? Get all your friends from around the world to wait for a very elusive – if not short-lived – special event. And in doing so, you may find something completely unexpected. Enter James Elliot from MIT, who worked with dozens of observatories and astronomers across the globe, including Jay Pasachoff from Williams College in Massachusetts, in an attempt to make observations of the Kuiper Belt Object 55636, (also known as 2002 TX300) a small body orbiting about 48 AU away from the Sun. Since this KBO is too small and distant for direct observations of its surface, the astronomers tracked and plotted its course, figuring out when it would pass in front of a distant star.
The KBO occulted, or passed in front of a bright background star, an event which lasted only 10 seconds. But in that short amount of time, the astronomers were able to determine the object’s size and albedo. Both of these results were surprising.
55636 was found to be smaller than previously thought, 300km in diameter, but it is highly reflective, meaning it is covered in fresh, white ice.
Most known KBOs have dark surfaces due to space weathering, dust accumulation and bombardment by cosmic rays, so 55636’s brightness implies it has an active resurfacing mechanism, or perhaps that in some cases, fresh water ice can persist for billions of years in the outer reaches of the Solar System. One graph of the occultation from the Las Cumbres Observatory. Credit: Elliot, et al.
42 astronomers from 18 observatories located in Australia, New Zealand, South Africa, Mexico and the US were part of the observations, but because of weather and timing, only two observatories, both in Hawaii, were able to detect the occultation. Working with Wayne Rosing, Pasachoff coordinated the observations at the Las Cumbres Observatory Global Telescope Network located at Haleakala Crater on Maui, Hawaii, which made the best observations.
But Pasachoff told Universe Today that having two different angles of view to work with provided the ability to make quite precise measurements of the KBO.
“It was absolutely crucial to have the second observation site,” he said. “Without it, we
would not have known where on a round or elliptical body the chord, the line of occultation, passed and we could not have set an upper limit to the size of the body.”
A chord near the edge of a huge body can be vanishingly small, Pasachoff added, illustrating why they needed at least two chords.
Although the surfaces of other highly reflective bodies in the solar system, such as the dwarf planet Pluto and Saturn’s moon Enceladus, are continuously renewed with fresh ice from the condensation of atmospheric gases or by cryovolcanism that spews water instead of lava, 55636 is too small for these mechanisms to be at work.
“The surprising thing in a billion-year-old object that is so reflective is that it maintained or renewed its reflectivity,” said Pasachoff, “so possibilities include the darkening that we know takes place in the inner solar system is much less way out there; or the object renews its ice or frost from inside. We need new observations or more KBO’s with occultations, and we need more theoretical work.”
This was the first successful “planned” observation of a KBO using the stellar occultation method. In 2009 another team scoured through four and a half years of Hubble data to find on occultation of an extremely small KBO 975 meters (3,200 feet) across and a whopping 6.7 billion kilometers (4.2 billion miles) away.
For several years, Pasachoff and his team from Williams College have worked with Elliot and others from MIT, as well as Amanda Gulbis of the South African Astronomical Observatory to study Pluto by occultation. With careful measurements of a star’s brightness as Pluto hides or occults it, they have shown that Pluto’s atmosphere was slightly warming or expanding. A main goal now is to find out how the atmosphere is changing. This will be especially significant with the New Horizons spacecraft en route to Pluto.
Pasachoff said he knew 55636’s albedo would be bright, but was surprised how bright it was. The origins of this object is believed to come from a collision that occurred one billion years ago between one of the three known dwarf planets in the Kuiper Belt, Haumea and another object that caused Haumea’s icy mantle to break into a dozen or so smaller bodies, including 55636.
“Mike Brown (KBO and dwarf planet hunter from Caltech) told me last year, before the observations, that the object would be reflective since it is in the Haumea family, and Haumea itself has a high albedo,” Pasachoff said.
Pasachoff worked with Brown and his team last year in trying to capture the mutual occultations of transits of Haumea with its moon Namaka using the Palomar 5-meter telescope, but they weren’t successful in detecting the extremely small effect, given Haumea’s rapid rotation period.
Elliot used the occultation method to discover the rings of Uranus decades ago and continues to champion the method.
Pasachoff said the recent observation of 55636 was very rewarding. “It was an incredible observation, and I was very pleased to be part of it.” He said. “I am proud that all three of the graphs in the Nature article, and both of the successful observations, were arranged or made by our Williams College team.”
He added that any such observation includes at least these four elements: astrometric predictions, observations, reduction of data, interpretation.
“We were very fortunate and interested in being successful with observations,” Pasachoff said. “But it is important to note that Jim Elliot and his colleagues at MIT and Lowell Observatory have been working for years to refine the methods of predictions to get them accurate enough for this purpose. And this event was the first time that the predictions had been accurate enough to merit the all-out press of telescopes that we assembled. That we picked up the event, near the center of the prediction to boot, is a credit to the astrometry team.”
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The equatorial circumference of the Moon is 10,916 km. And the circumference of the Moon in miles is 6,783 miles. So, if you wanted to drive your lunar rover around the Moon and return back where you started, you’d need to travel 10,916 kilometers.
Need some comparison? The equatorial circumference of the Earth is 40,075 km. That makes the size of the Moon’s circumference about 27.24% the size of the Earth.
The Moon isn’t the largest moon in the Solar System – it only has an equatorial radius of 1,737.4 km. The largest moon is Jupiter’s moon Ganymede, with an equatorial radius of 2,634 km. That means Ganymede’s circumference is 16,550 km; bigger than the Moon’s circumference by about 5,634 km.
Want some more measurements?
The circumference of the Moon in meters: 10,916,000 meters
The circumference of the Moon in centimeters: 1,091,600,000 centimeters
The circumference of the Moon in feet: 35,813,648 feet
The circumference of the Moon in inches: 429,763,780 inches
We’ve written many articles about the Moon for Universe Today. Here’s an article about the full Moon, and here’s an article about the atmosphere of the Moon.
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The equatorial circumference of Saturn is 378,675 km (or 235,298 miles). Not that it’s actually possible, but if you wanted to drive your car around Saturn’s equator, that’s how far you’d have to travel. Just for comparison, the equatorial circumference of Earth is 40,075 km, so Saturn’s circumference is 9.4 times larger than the Earth.
Want to make the calculation for yourself? Well, the formula for calculating the circumference of a circle is 2 x pi x r, where R is the radius of the circle. The equatorial radius of Saturn is 60,268 km, so you can do the math yourself.
Of course, Saturn isn’t the largest planet in the Solar System, that’s Jupiter. Jupiter’s circumference is 449,197 km, or 1.19 times bigger than Saturn. And the largest object in the Solar System is the Sun, with an equatorial circumference of 4,379,000 km. That’s 11.56 times bigger than Saturn.
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Jupiter is the 5th planet from the Sun, and the largest planet in the Solar System. How much bigger is Jupiter than Earth? Just to give you a sense of scale, Jupiter is 2.5 times more massive than all the rest of the planets in the Solar System combined.
Jupiter’s diameter is 11.2 times larger than Earth. In other words, you could put 11.2 Earths side-by-side to match the diameter of Jupiter.
And Jupiter’s volume is even bigger. It would take 1321.3 Earths to fill up the volume of Jupiter. In terms of surface area, Jupiter is 121.9 times bigger than the Earth. That’s how many Earths could be flattened out to cover the surface of Jupiter.
Jupiter has 317.8 times the mass of the Earth.
Even though Jupiter is an enormous, massive planet, it’s much smaller than the Sun. The Sun accounts for 99.86% of the mass of the Solar System. You could fit 109 Earths side by side to match the diameter of the Sun, and it would take 1.3 million planets the size of the Earth to fill it up.
We’ve written many articles about Jupiter for Universe Today. Here’s an article about pictures of Jupiter, and here’s an article about missions to Jupiter.
Mars500 participant Diego Urbina (follow him on Twitter at @diegou) provides a tour inside the Mars500 facilities – see how the crew are living and working for the next 17 months in isolation. On June 3, 2010 Urbina and five fellow crewmates from Europe, Russia and China embarked on a 520-day mock mission to Mars, and are living in a crew module in a warehouse in Moscow. See our preview article here.
