Color-composite image of Titan and Saturn (NASA/JPL/SSI/J. Major)
Here’s a great shot of Titan and Saturn acquired by Cassini on May 6, 2012 just after a pass by the haze-covered moon. It’s a color-composite made from images taken in Cassini’s red, green and blue color channels, and the resulting image was color adjusted a bit to appear more “Saturny”.
UPDATE 7/2/12: The image above is featured in today’s Astronomy Picture of the Day (APOD)… check it out here.
Cassini also made some closer passes of Titan on May 6, taking images within about 710,000 km. After recent passes of Encealdus and Dione, Cassini buzzed past Titan in preparation of a targeted flyby on May 22, after which it will head up and out out of the “moonplane” in order to get a better view of Saturn’s rings and upper latitudes.
After that, Cassini won’t be playing amongst the moons again for three years, so images like this will be a rarity for a while.
Another image of Titan, closer-in and set against Saturn’s rings and clouds, shows the fine, transparent structure of the moon’s upper atmospheric haze layers:
Created by the breakdown of methane in Titan’s opaque atmosphere by UV radiation, the haze is composed of complex hydrocarbons that extend outwards up to ten times the thickness of Earth’s atmosphere!
(The RGB layers weren’t available for this particular view, so there’s no color version of it.)
Check out previous images from Cassini’s flyby of Dione and Enceladus, and follow along with the Cassini mission on the JPL site here.
Top image: Color-composite image of Titan and Saturn (NASA/JPL/SSI/J. Major) Bottom image: Titan in blue wavelength against Saturn (NASA/JPL/SSI)
Diagram of a proposed current generation of a Starship Enterprise. Credit: BuildTheEnterprise.org
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In Star Trek lore, the first Constitution Class Starship Enterprise will be built by the year 2245. But today, an engineer has proposed — and outlined in meticulous detail – building a full-sized, ion-powered version of the Enterprise complete with 1G of gravity on board, and says it could be done with current technology, within 20 years. “We have the technological reach to build the first generation of the spaceship known as the USS Enterprise – so let’s do it,” writes the curator of the Build The Enterprise website, who goes by the name of BTE Dan.
This “Gen1” Enterprise could get to Mars in ninety days, to the Moon in three, and “could hop from planet to planet dropping off robotic probes of all sorts en masse – rovers, special-built planes, and satellites.”
Size comparisons of buildings to the proposed USS Enterprise. Credit: BuildTheEnterprise.org
Complete with conceptual designs, ship specs, a funding schedule, and almost every other imaginable detail, the BTE website was launched just this week and covers almost every aspect of how the project could be done. This Enterprise would be built entirely in space, have a rotating gravity section inside of the saucer, and be similar in size with the same look as the USS Enterprise that we know from Star Trek.
“It ends up that this ship configuration is quite functional,” writes BTE Dan, even though his design moves a few parts around for better performance with today’s technology. This version of the Enterprise would be three things in one: a spaceship, a space station, and a spaceport. A thousand people can be on board at once – either as crew members or as adventurous visitors.
While the ship will not travel at warp speed, with an ion propulsion engine powered by a 1.5GW nuclear reactor, it can travel at a constant acceleration so that the ship can easily get to key points of interest in our solar system. Three additional nuclear reactors would create all of the electricity needed for operation of the ship.
The saucer section would be a .3 mile (536 meter) diameter rotating, magnetically-suspended gravity wheel that would create 1G of gravity.
The first assignments for the Enterprise would have the ship serving as a space station and space port, but then go on to missions to the Moon, Mars, Venus, various asteroids and even Europa, where the ships’ laser would be used not for combat but for cutting through the moon’s icy crust to enable a probe to descend to the ocean below.
Of course, like all space ships today, the big “if” for such an ambitious effort would be getting Congress to provide NASA the funding to do a huge 20-year project. But BTE Dan has that all worked out, and between tax increases and spreading out budget cuts to areas like defense, health and human services, housing and urban development, education and energy, the cuts to areas of discretionary spending are not large, and the tax increases could be small. “These changes to spending and taxes will not sink the republic,” says the website. “In fact, these will barely be noticed. It’s amazing that a program as fantastic as the building a fleet of USS Enterprise spaceships can be done with so little impact.”
“The only obstacles to us doing it are the limitations we place on our collective imagination,” BTE Dan adds, and his proposal says that NASA will still receive funding for the science, astronomy and robotic missions it currently undertakes.
A detailed schedule of building the Enterprise. Credit: BuildTheEnterprise.org
But he proposes not just one Enterprise-class ship, but multiple ships, one of which can be built every 33 years – once per generation – giving three new ships per century. “Each will be more advanced than the prior one. Older ships can be continually upgraded over several generations until they are eventually decommissioned.”
BTE Dan, who did not respond to emails, lists himself as a systems engineer and electrical engineer who has worked at a Fortune 500 company for the past 30 years.
The website includes a blog, a forum and a Q&A section, where BTE Dan answers the question, “What if someone can prove that building the Gen1 Enterprise is beyond our technological reach?”
Answer: “If someone can convince me that it is not technically possible (ignoring political and funding issues), then I will state on the BuildTheEnterprise site that I have been found to be wrong. In that case, building the first Enterprise will have to wait for, say, another half century. But I don’t think that anyone will be able to convince me it can’t be done. My position is that we can – and should – immediately start working on it.”
Image of the Thor's Helmet nebula (NGC 2359) Credit: R. Barrena (IAC) and D. López
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Going to see the new Avengers movie this weekend, either for the first or fortieth time? You may not see much of Thor’s helmet in the film (as he opts for more of a “Point Break” look) but astronomers using the Isaac Newton Group of telescopes on the Canary Islands have succeeded in spotting it… in this super image of the Thor’s Helmet nebula!
Named for its similarity to the famous horned Viking headgear (seen horizontally), the Thor’s Helmet nebula is a Wolf-Rayet structure created by stellar winds from the star seen near the center blowing the gas of the bluish “helmet” outwards into space via pre-supernova emissions.
The colors of the image above, acquired with the ING’s Isaac Newton Telescope, correspond to light emitted in hydrogen alpha, doubly-ionised oxygen and single-ionised sulfur wavelengths.
Super-sized for the thunder god himself, Thor’s Helmet measures at about 30 light-years across. It’s located in the constellation Canis Major, approximately 15,000 light-years from Earth. (You’d think Thor would have left his favorite accessory in a more convenient location… I suspect Loki may be behind this.)
Astronomers, assemble!
Read more about this and see other images from the ING telescopes here.
The Isaac Newton Group of Telescopes (ING) is owned by the Science and Technology Facilities Council (STFC) of the United Kingdom, and it is operated jointly with the Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO) of the Netherlands and the Instituto de Astrofísica de Canarias (IAC) of Spain. The telescopes are located in the Spanish Observatorio del Roque de los Muchachos on La Palma, Canary Islands, which is operated by the Instituto de Astrofísica de Canarias (IAC).
Full-disk image of Earth from Russia's Elektro-L satellite. (NTs OMZ)
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Unlike most satellite images of Earth, this one was not assembled from multiple swath scans or digitally projected onto a globe model — it’s the full disk of our planet in captured as a single, enormous 121 megapixel image, acquired by Russia’s Elektro-L weather-forecasting satellite.
Like NASA’s GOES satellites, Elektro-L is parked in a geostationary orbit approximately 36,000 km (22,300 miles) above our planet. Unlike NASA’s satellites, however, Elektro-L captures images in near-infrared as well as visible wavelengths, providing detail about not only cloud movement but also vegetation variations. Its wide-angle Multichannel Scanning Unit (MSU) takes images every 15-30 minutes, showing the same viewpoint of Earth across progressive times of the day.
At a resolution of 0.62 miles per pixel, full-size Elektro-L images are some of the most detailed images of Earth acquired by a weather satellite.
Download the full-size image here (100+ megabytes).
Launched aboard a Zenit rocket on January 20, 2011, Elektro-L was the first major spacecraft to be developed in post-Soviet Russia. Parked over Earth at 76 degrees east longitude, Elektro-L provides local and global weather forecasting and analysis of ocean conditions, as well as “space weather” monitoring — measurements of solar radiation and how it interacts with Earth’s magnetic field. Its initial lifespan is projected to be ten years.
A second Elektro-L satellite is anticipated to launch in 2013.
Image credit: Russian Federal Space Agency / Research Center for Earth Operative Monitoring (NTS OMZ). See more images and video from Elektro-L on James Drake’s Planet Earth here. (Tip of the geostationary hat to Jesus Diaz at Gizmodo.)
Sagittarius Teapot Asterism Author Eoghanacht via wikimedia commons
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Humans have been grouping stars into patterns since the beginning of time, each culture placing its own myths and folklore in the sky, but it wasn’t until 1930 that the International Astronomical Union (IAU) divided the sky into 88 constellations each with its own strict boundary. Though many of these are well known, and the stories they depict are well documented, few look like the figures they are supposed to represent. Asterisms are more user friendly guides and the starting point for most astronomers. These bright, simple, more prosaic shapes, stand out among the constellations and often serve as useful landmarks, pointing the way to celestial delights!
The best known and most instantly recognisable asterism is probably the Plough or Big Dipper in Ursa Major. Two of its stars, Merak and Dubhe, (The Pointers) pointing the way to the North Star Polaris in Ursa Minor. NASA’s Juno spacecraft stopped on its 5 year journey to Jupiter on March 21 to capture this image of our best known asterism:
The Big Dipper by Juno Credit: NASA/JPL-Caltech/SWRI/MSSS
In the Northern hemisphere, each season is heralded by its own asterism: The Autumn sky is dominated by the great Square of Pegasus, formed by stars from both Pegasus and Andromeda and its top left corner points the way to the Andromeda Galaxy, just a hop, skip and jump away. Most people recognise the three stars Alnitak, Alnilam and Mintaka, making up the Belt of Orion, which shines bright in the Winter sky indicating one of the richest regions in the sky, the Orion Molecular Cloud Complex. The Diamond of Virgo marking the Spring, consists of Arcturus (Boötes), Spica (Virgo), Denebola (Leo) and Cor Caroli (Canes Venatici). These encompass the constellation Coma Berenices and many of the galaxies within the Virgo Cluster. The Summer Triangle of Deneb (Cygnus), Altair (Aquila), and Vega (Lyra) currently sails over us guiding the way to the Ring Nebula in its top right corner.
Searching for Leo? Look for the Sickle, a backwards question mark that represents the lion’s head. Hunting for Hercules? The Keystone is the key and you will also find the Hercules Cluster (M13) on its right hand side. Boötes is easier to spot if you look for the Kite or Ice Cream Cone, than try to make out an ox driver! Not many people can see poor Queen Cassiopia, punished for her vanity to circle the heavens, but the W that marks the constellation is instantly recognisable. The Circlet is a lovely signpost to one of the fish of Pisces. You’d be hard pressed to recognise Sagittarius as the centaur it depicts, but there is the Teapot (Bertrand Russell was right, there is a celestial teapot!) showing the way to this rich patch of sky.
The Southern hemisphere has no shortage of asterisms either, most notably Argo Navis which represents the entire ship Argo sailed by Jason and the Argonauts and would be the largest constellation in the sky if it hadn’t been broken up in 1752 by French astronomer Nicolas Louis de Lacaille into the constellations we know today as Carina (the keel), Puppis (the poop deck) and Vela (the sails). Also in the Southern hemisphere are found The Three Patriachs in Triangulum Australe and the Fish Hook in Scorpius among others.
There are many more obscure asterisms too. Job’s Coffin graces the constellation of Delphinus, Asses and the Manger are in Cancer, Poniatowski’s bull (named for the King of Poland) is part of Ophiuchus and Aquila. There are the Lozenge, Saxophone, Coathanger, and many more.
The sky can seem a bewildering place, filled with gods, kings and mythical creatures. Asterisms like the Teapot make a more welcoming and friendly introduction, allowing a novice stargazer to easily pick their way around the sky and gain confidence and as many stars get swallowed by increasing light pollution, asterisms still shine out to show the way.
I’ve been waiting for nearly two months to be able to share these videos from the Dawn mission’s “flyover” views of Vesta. Scientists showed some of these incredible views at the Lunar and Planetary Science Conference in March, but couldn’t make them public until they published their work in the journal Science.
“Vesta is unlike any other object we’ve visited in the solar system,” said Dawn mission team member Vishnu Reddy at a briefing today. “We see a wide range of variation on the surface, with some areas bright as snow, and other areas as dark as coal.”
The video above is a stunningly beautiful flyover of most of Vesta. Another video, below, takes viewers on a virtual tour of Vesta’s south polar basin, the ‘snowman’ set of craters and a crater called Oppia.
Scientists said today that Vesta more closely resembles a small planet or Earth’s Moon than another asteroid, and they now have a better understanding of both Vesta’s surface and interior, and can conclusively link Vesta with meteorites that have fallen on Earth.
So much for the world ending on December 21, 2012. We’ve been saying it for years, but a new find by archaeologists confirms the Mayan calendar indeed does not end this year but keeps going, just like turning a page to a new calendar.
“It’s very clear that the 2012 date, while important as Baktun 13, was turning the page,” David Stuart, quoted by Alan Boyle on MSNBC’s Cosmic Log. “Baktun 14 was going to be coming, and Baktun 15 and Baktun 16. … The Maya calendar is going to keep going, and keep going for billions, trillions, octillions of years into the future.”
A team of archaeologists found a small room in Mayan ruins where royal scribes wrote on the walls — apparently like a blackboard — to keep track of astronomical records and details of the complex Mayan calendar. The writings date to about 1,200 years ago.
These are the oldest known astronomical tables from the Maya. They were found at the Xultun archaeological site in Guatemala’s Peten region. Scientists already knew the Mayans must have been keeping such records during that time period, but until now the oldest known examples dated from about 600 years later.
The room, about 2 meters (6-feet) square, contains walls decorated with images of a king and some other notable figures, as well as astronomical numbers and writings, the scientists said. The room had a stone roof rather than a thatched one, which may indicate the importance of the room.
Why did they write on walls, as opposed to other Mayan texts that have been found on bark paper?
The time period of the early 9th century was not a stable time for the Mayans, as there was political turmoil between the various city-states of the time, and the researchers said that perhaps the Xultun scribes wished to make a more permanent record of their data related to the calendar.
By some supposed “researchers,” Dec. 21, 2012 has been correlated to the end of the Mayan Long Count calendar, which was based on a cycle of 13 intervals known as baktuns, each lasting 144,000 days.
But the newly found writing on walls of the ancient room shows wide ranges of accumulated time, including a 17-baktun period. “There was a lot more to the Maya calendar than just 13 baktuns,” said Stuart, talking with reporters. Seventeen baktuns would stand for about 6,700 years, which is much longer than the 13-baktun cycle of 5,125 years. However, Stuart cautioned that the time notation shouldn’t be read as specifying a date that’s farther in the future than Dec. 21.
“It may just be that this is a mathematical number that’s kind of interesting,” he said. “We’re not sure what the base of the calendar is.”
William Saturno, an archaeologist at Boston University who led the team of archaeologists said many different scientists have been trying to get the word out that the end of the Maya culture’s 13-baktun Long Count calendar doesn’t signify the end of the world, but merely a turnover to the next cycle in a potentially infinite series — like going from Dec. 31 to Jan. 1 on a modern calendar.
“If someone is a hard-core believer that the world is going to end in 2012, no painting is going to convince them otherwise,” he said. “The only thing that can convince them otherwise is waiting until Dec. 22, 2012 — which fortunately for all of us isn’t that far away.”
For a quarter century, researchers believed a bow "shock" formed ahead of the heliosphere as it moved through interstellar space – similar to the sonic boom made by a jet breaking the sound barrier. New data from NASA's Interstellar Boundary Explorer (IBEX) shows that the heliosphere moves through space too slowly to form a bow shock. Credit: Southwest Research Institute.
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For years, scientists have thought a bow “shock” formed ahead of our solar system’s heliosphere as it moved through interstellar space – similar to the sonic boom made by a jet breaking the sound barrier. But new data from NASA’s Interstellar Boundary Explorer (IBEX) shows that our system and its heliosphere move through space too slowly to form a bow shock, and therefore does not exist. Instead there is a more gentle ‘wave.’
“While bow shocks certainly exist ahead of many other stars, we’re finding that our Sun’s interaction doesn’t reach the critical threshold to form a shock,” said Dr. David McComas, principal investigator of the IBEX mission, “so a wave is a more accurate depiction of what’s happening ahead of our heliosphere — much like the wave made by the bow of a boat as it glides through the water.”
From IBEX data, McComas and his team were able to make refinements in relative speed of our system, as well as finding more information about the local interstellar magnetic field strength. IBEX data have shown that the heliosphere actually moves through the local interstellar cloud at about 52,000 miles per hour, roughly 7,000 miles per hour slower than previously thought. That is slow enough to create more of a bow “wave” than a shock.
Bow shocks exist around other astrospheres, as seen in these images taken by multiple telescopes. New IBEX data show that our heliosphere moves through interstellar space too slowly to produce a bow shock, creating more of a “wake” as it travels through space. Image courtesy of Southwest Research Institute
Another influence is the magnetic pressure in the interstellar medium. IBEX data, as well as earlier Voyager observations, show that the magnetic field is stronger in the interstellar medium requiring even faster speeds to produce a bow shock. Combined, both factors now point to the conclusion that a bow shock is highly unlikely.
The IBEX team combined its data with analytical calculations and modeling and simulations to determine the conditions necessary for creating a bow shock. Two independent global models — one from a group in Huntsville, Ala., and another from Moscow — correlated with the analytical findings.
Their paper was published today in the journal Science.
How does this new finding change our understanding of our heliosphere?
“It’s too early to say exactly what this new data means for our heliosphere,” McComas said. “Decades of research have explored scenarios that included a bow shock. That research now has to be redone using the latest data. Already, we know there are likely implications for how galactic cosmic rays propagate around and enter the solar system, which is relevant for human space travel.”
Artist's rendering of an Earth-sized rogue planet approaching a star. Credit: Christine Pulliam (CfA)
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Free-floating “rogue” planets may occasionally dip into the inner Solar System, picking up dust containing organic compounds — a.k.a. the ingredients for life — and carry it back out into the galaxy, according to new research by Professor Chandra Wickramasinghe, Director of the University of Buckingham Centre for Astrobiology in the UK.
Rogue planets are thus called because they are not in orbit around a star. Either forcibly ejected from a solar system or having formed very early on in the Universe — even within a few million years after the Big Bang, the team proposes — these vagrant worlds may vastly outnumber stars. In fact, it’s been suggested there are as much as 100,000 times more rogue planets than stars in our Milky Way galaxy alone!
Professor Wickramasinghe — a proponent of the panspermia hypothesis whereby the ingredients for life can be transported throughout the galaxy on dust, comets, and perhaps even planets — and his team have suggested in a paper published in the journal Astrophysics and Space Science that Earth-sized rogue planets could pass through the inner Solar System, possibly as often as once every 25 million years on average. Like a cosmic drive-thru these planets could gather zodiacal dust from the plane of the Solar System during their pass, thus picking up organic compounds along the way.
The planets would then take the material gathered from one solar system and possibly bring it into another, serving as a type of interstellar cross-pollinator.
Wickramasinghe’s team propose that, by this process, there could be more life-bearing, Earth-sized planets existing between the stars than orbiting around them — a lot more. Based on their estimates there may be as much as a few hundred thousand billion such worlds in our galaxy… that’s several thousand for every star.
It will be interesting to see how this idea is received, but it definitely is an intriguing concept. As we hunt for the “Holy Grail” of life-friendly exoplanets around other stars, they may be drifting through the darkness in number, hiding in the spaces between.
This new view of the Cygnus-X star-formation region by Herschel highlights chaotic networks of dust and gas that point to sites of massive star formation. Credits: ESA/PACS/SPIRE/Martin Hennemann & Frédérique Motte, Laboratoire AIM Paris-Saclay, CEA/Irfu – CNRS/INSU – Univ. Paris Diderot, France.
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In infrared, Cygnus-X is a glowing star nursery, and the Herschel space observatory has captured this beautiful new view showing an extremely active region of big-baby stars. It is located about 4,500 light-years from Earth in the constellation of Cygnus, the Swan. The image highlights the unique capabilities of Herschel to probe the birth of large stars and their influence on the surrounding interstellar material.
The bright white areas are where large stars have recently formed out of turbulent clouds, especially evident in the chaotic network of filaments seen in the right-hand portion of the image. The dense knots of gas and dust collapse to form new stars; the bubble-like structures are carved by the enormous radiation emitted by these stars.
In the center of the image, fierce radiation and powerful stellar winds from stars undetected at Herschel’s wavelengths have partly cleared and heated interstellar material, which then glows blue. The threads of compact red objects scattered throughout the image shows where future generations of stars will be born.
