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Neptune orbits much further away from the Sun than the Earth, so its orbit takes much longer. In fact, Neptune takes 164.79 years to orbit around the Sun. That’s almost 165 times longer than Earth takes to orbit the Sun.
Here’s an interesting fact. Neptune was only discovered on September 23, 1846. At the time this article was written (2009), that was only 163 years ago. In other words, since its discovery, Neptune has not even made a single orbit around the Sun.
On July 11, 2011, Neptune will have completed one full orbit around the Sun. Finally, Neptune will be 1 year old.
Just like Earth, Neptune’s axis is tilted away from the Sun’s axis. This means that it experiences seasons as it orbits the Sun. For half of its orbit, Neptune’s northern hemisphere is tilted towards the Sun, and then for the second half of its orbit, its southern hemisphere is tilted towards the Sun. This differential heating creates very powerful winds on Neptune. In fact, Neptune has the strongest sustained winds on the Solar System, with winds measured at 2100 km/hour.
Here’s this week’s image for the WITU Challenge, to test your visual knowledge of the cosmos. You know what to do: take a look at this image and see if you can determine where in the universe this image is from; give yourself extra points if you can name the spacecraft responsible for the image. We’ll provide the image today, but won’t reveal the answer until tomorrow. This gives you a chance to mull over the image and provide your answer/guess in the comment section. Please, no links or extensive explanations of what you think this is — give everyone the chance to guess.
UPDATE: The answer has been posted below.
This object is the remains of a Type Ia supernova caused by the thermonuclear explosion of a white dwarf. It is called SNR 0104-72.3 (SNR 0104 for short), and is in the Small Magellanic Cloud, a small neighboring galaxy to the Milky Way. The image was taken by the Chandra X-Ray Observatory. The asymmetrical shape of this object is unusual for such a supernova and astronomers think this might be caused by jets in the explosion or clumps of nearby gas.
Close-up view of Apollo 12 landing site from LRO. Credit: NASA/GSFC/Arizona State University
Wow! Just look at the detail visible in this image of the Apollo 12 landing site taken by the Lunar Reconnaissance Orbiter from its lower mapping orbit of 50 km above the surface. Compared to earlier images taken in September when LRO was in a higher orbit, the Lunar Module descent stage really stands out, as well as the Apollo Lunar Surface Experiment Package (ALSEP). Also visible are the trails left by spacewalking astronauts. From this and other LROC landing site images, it is clear that astronaut activity lowers the albedo, or reflectivity of the surface. Areas of heaviest activity have the lowest albedo, especially around the LM. NASA says this effect is most likely due to compaction of a very loose surface powder by the astronauts just walking around.
The Apollo 12 landing site as seen by LRO. Credit: NASA/GSFC/Arizona State University
Here is a slightly more zoomed out version that includes the Surveyor 3 spacecraft. The Sun is very high in the sky (incidence angle 4°) for these images and shadows are minimized.
Below is an image taken by the astronauts as they set up the ALSEP instruments.
Future Mars astronauts. Image Credit: Patrick McGuire
Ever heard of a ‘Cyborg Astrobiologist’? Probably not. But I bet you’ll want to be one after learning that future exploration of Mars (and other planets, for that matter) may employ the use of artificial intelligence integrated into spacesuits to enhance the ability of astronauts in taking scientific data while exploring. The AI assistance could help future astronauts exploring planets to recognize differences in their surroundings as being due to the presence of life. Does this sound like something from 50 years from now? Well, a prototype model has already been tested, and has shown the principle behind this idea to be sound.
University of Chicago geoscientist Patrick McGuire and his team have developed the basic systems needed for such a spacesuit, using mostly off-the shelf technology. The system uses a Hopfield neural network to analyze data taken in by a either a camera phone or a microscope. The AI system employs a ‘novelty detection algorithm’ which analyzes images from either imaging device, and is able to identify features in images that are out of place.
The Hopfield system compares patterns against ones it has already seen, and learns from this process to correctly identify novel patterns that could be of interest. The full prototype spacesuit has a wearable computer that houses the AI system, which uses Bluetooth to receive data from a cell phone camera or is connected to a USB digital microscope.
The system was tested at the Mars Desert Research Station (MDRS) in the San Rafael Swell of Utah, which is maintained by the Mars Society. The MDRS is a semi-arid desert with “greenish, grey or light gray mudstone,
limestone, siltstone and sandstone, partially inter-bedded by white sandstone layers”. For the last two weeks of February 2009, two members of McGuire’s team tested the wearable technology, which was able to successfully learn to identify patches of lichen from a background of rock, and identify different color patterns that signified different rock formations.
Another test, conducted in September of 2005 at Rivas Vaciamadrid in Spain, utilized a USB digital microscope to image rocks with lichen on them. As you can see in the image below, the AI system was able to identify as uncommon the spores of the lichen, which are about 1mm in diameter.
There are still some bugs to be worked out, though, as the system detected cast shadows in rough terrain our low standing Sun as novel features, the researchers wrote in their paper, The Cyborg Astrobiologist: Testing a Novelty-Detection Algorithm on Two Mobile Exploration Systems at Rivas Vaciamadrid in Spain and at the Mars Desert Research Station in Utah, available on Arxiv. The researchers also tested a head-mounted digital microscope display, but instead opted for a tripod due to the blurriness associated with the head movement of the researcher wearing the suit.
Though it may be a while until there are any Martian astronauts utilizing such a system – let alone Martian astronauts with the title of ‘Cyborg Astrobiologist’ – the combination of the AI with imaging systems could start to prove very useful on future orbital surveyors of Mars. Additionally, these systems could be used to collect and analyze data outside of the visible light spectrum, which could be incredibly useful for both robotic and human explorers.
NASA’s Spitzer Space Telescope captured this infrared image of a giant halo of very fine dust around the young star HR 8799. Image credit: NASA/JPL-Caltech/Univ. of Ariz.
Just what is going on over at the star HR 8799? The place is a mess! But we can just blame it on the kids. Young, hyperactive planets circling the star are thought to be disturbing smaller comet-like bodies, causing them to collide and kick up a huge halo of dust. HR 8799 was in the news in November 2008, for being one of the first with imaged planets. Now, NASA’s Spitzer Space Telescope has taken a closer look at this planetary system and found it to be a very active, chaotic and dusty system. Ah, youth: our solar system was likely in a similar mess before our planets found their way to the stable orbits they circle in today.
The Spitzer team, led by Kate Su of the University of Arizona, Tucson, says the giant cloud of fine dust around the disk is very unusual. They say this dust must be coming from collisions among small bodies similar to the comets or icy bodies that make up today’s Kuiper Belt objects in our solar system. The gravity of the three large planets is throwing the smaller bodies off course, causing them to migrate around and collide with each other. Astronomers think the three planets might have yet to reach their final stable orbits, so more violence could be in store. The planets around HR 8799 are about 10 times the mass of Jupiter.
“The system is very chaotic and collisions are spraying up a huge cloud of fine dust,” said Su. “What’s exciting is that we have a direct link between a planetary disk and imaged planets. We’ve been studying disks for a long time, but this star and Fomalhaut are the only two examples of systems where we can study the relationships between the locations of planets and the disks.”
When our solar system was young, it went through similar planet migrations. Jupiter and Saturn moved around quite a bit, throwing comets around, sometimes into Earth. Some say the most extreme part of this phase, called the late heavy bombardment, explains how our planet got water. Wet, snowball-like comets are thought to have crashed into Earth, delivering life’s favorite liquid.
The Spitzer results were published in the Nov. 1 issue of Astrophysical Journal. The observations were made before Spitzer began its “warm” mission and used up its liquid coolant.
The comet chasing spacecraft Rosetta will make its third and final swing by the Earth on November 13th to pick up more speed for the last part of a 10-year journey that lies ahead. Its mission is to place a lander on comet 67P/Churyumov-Gerasimenko and chase the comet for an entire year on its orbit around the Sun. The spacecraft will be visible to observers from the ground in certain locations on the Earth. This last flyby will increase the spacecraft’s speed by 3.6 km/s (2.2 miles/s) with respect to the Sun, giving Rosetta the energy it needs to boost it to the outer regions of the Solar System.
Rosetta was launched March 2nd, 2004, and will visit a host of targets on its way to comet 67P/Churyumov-Gerasimenko. Rosetta already paid a visit to asteroid 2867 Steins in September 2008. It will visit comet 21 Lutetia 10 June 2010, after which it will go into hibernation until it reaches its final destination in May 2014.
Once Rosetta arrives at 67P/Churyumov-Gerasimenko, it will deploy its Philae lander on the comet’s nucleus, and continue to orbit and study the comet for an entire year during its closest orbit of the Sun. This is the first mission ever to orbit and land on a comet, and promises to return a wealth of data on cometary interaction with the Sun. Comets also contain mostly undisturbed materials from the formation of the Solar System in their nuclei, so studying their composition gives scientists an look into how our Solar System developed.
During the flyby of Earth in November of 2007, Rosetta took the breathtaking image of the Earth pictured here. This next flyby will give observers on the ground a chance to take a look back at Rosetta. The closest approach will occur on November 13th at 8:45 Central European Time (07:45 UT).
Unfortunately, the spacecraft will only be visible from parts of Europe, South America and Africa, as can be seen in the image below. If you are in these regions during the approach, and have favorable conditions, there is a wealth of observing information on the Rosetta blog, specifically on the posts Tips for Sky Junkies I and Tips for Sky Junkies II. They will also be closely following the flyby on the blog, so you can check there for updates on the eve of the event if you are outside the observable range of the spacecraft.
As always, you can check back with us on Universe Today for more coverage of Rosetta’s journey!
A Chandra X-ray Observatory image of the supernova remnant Cassiopeia A. Credit: NASA/CXC
Supernova remnant Cassiopeia A (Cas A) has always been an enigma. While the explosion that created this supernova was obviously a powerful event, the visual brightness of the outburst that occurred over 300 years ago was much less than a normal supernova, — and in fact, was overlooked in the 1600’s — and astronomers don’t know why. Another mystery is whether the explosion that produced Cas A left behind a neutron star, black hole, or nothing at all. But in 1999, astronomers discovered an unknown bright object at the core of Cas A. Now, new observations with the Chandra X-Ray Observatory show this object is a neutron star. But the enigmas don’t end there: this neutron star has a carbon atmosphere. This is the first time this type of atmosphere has been detected around such a small, dense object.
A Chandra X-ray Observatory image of the supernova remnant Cassiopeia A, with an artist's impression of the neutron star at the center of the remnant. The discovery of a carbon atmosphere on this neutron star resolves a ten-year old mystery surrounding this object. Credit: Chandra image: NASA/CXC/Southampton/W.Ho; illustration: NASA/CXC/M.Weiss
The object at the core is very small – only about 20 km wide, which was key to identifying it as a neutron star, said Craig Heinke from the University of Alberta. Heinke is co-author with Wynn Ho of the University of Southampton, UK on a paper which appears in the Nov. 5 edition of Nature.
“The only two kinds of stars that we know of that are this small are neutron stars and black holes,” Heinke told Universe Today. “We can rule out that this is a black hole, because no light can escape from black holes, so any X-rays we see from black holes are actually from material falling down into the black hole. Such X-rays would be highly variable, since you never see the same material twice, but we don’t see any fluctuations in the brightness of this object.”
Heinke said the Chandra X-ray Observatory is the only telescope that has sharp enough vision to observe this object inside such a bright supernova remnant.
But the most unusual aspect of this neutron star is its carbon atmosphere. Neutron stars are mostly made of neutrons, but they have a thin layer of normal matter on the surface, including a thin–10 cm–very hot atmosphere. Previously studied neutron stars all have hydrogen atmospheres, which is expected, as the intense gravity of the neutron star stratifies the atmosphere, putting the lightest element, hydrogen, on top.
But not so with this object in Cas A.
“We were able to produce models for the X-ray radiation of a neutron star with several different possible atmospheres,” Heinke said in an email interview. “Only the carbon atmosphere can explain all the data we see, so we are pretty sure this neutron star has a carbon atmosphere, the first time we’ve seen a different atmosphere on a neutron star.” An artist's impression of the neutron star in Cas A showing the tiny extent of the carbon atmosphere. The Earth's atmosphere is shown at the same scale as the neutron star. Credit: NASA/CXC/M.Weiss An artist’s impression of the neutron star in Cas A showing the tiny extent of the carbon atmosphere. The Earth’s atmosphere is shown at the same scale as the neutron star. Credit: NASA/CXC/M.Weiss
So how does Heinke and his team explain the lack of hydrogen and helium on this neutron star? Think of Cas A as being a baby.
“We think we understand that as due to the really young age of this object–we see it at the tender age of only 330 years old, compared to other neutron stars that are thousands of years old,” he said. “During the supernova explosion that created this neutron star (as the core of the star collapses down to a city-sized object, with an incredibly high density higher than atomic nuclei), the neutron star was heated to high temperatures, up to a billion degrees. It’s now cooled down to a few million degrees, but we think its high temperatures were sufficient to produce nuclear fusion on the neutron star surface, fusing the hydrogen and helium to carbon.”
Because of this discovery, researchers now have access to the complete life cycle of a supernova, and will learn more about the role exploding stars play in the makeup of the universe. For example, most minerals found on Earth are the products of supernovae.
“This discovery helps us understand how neutron stars are born in violent supernova explosions,” said Heinke.
Masten won the $1 million Northrop Grumman Lunar X-Prize challenge with their lander, Xoie.
The X-Prize competition for building a lander vehicle capable of making a simulated landing and liftoff on the Moon has come to a close, with the 1st place, $1 million award going to Masten Space Systems for their vehicle, Xoie (pronounced like the name ‘Zoey’). Armadillo Aerospace came in a close second, and received $500,000 for their Scorpius rocket. The Northrop Grumman Lunar Lander X-Prize challenge was initiated to spur development of lunar landing vehicle by a privately funded institution. The last of the challenge flights occured Friday, October 30th, and the competition came down to the wire, as Masten encountered problems on Wednesday and Thursday challenge windows that delayed their final flight to the last day of the challenge.
The challenge was divided into two categories, Level 1 and Level 2. Here’s the rules for the two categories, as taken from the X-Prize Foundation website:
Level 1, requires a rocket to take off from a designated launch area; climb to a low, fixed altitude; and fly for at least 90 seconds before landing precisely on a different landing pad. The flight must then be repeated in reverse. Both flights, along with all of the necessary preparation for each, must take place within a two and a half hour period. $500,000 in prizes was initially allocated to Level 1.
The more difficult course, Level 2, requires the rocket to fly for 180 seconds before landing precisely on a simulated lunar surface constructed with craters and boulders. The minimum flight times are calculated so that the Level 2 mission closely simulates the power needed to perform a real descent from lunar orbit down to the surface of the Moon. A $1 million First Place and a $500,000 second place prize remain to be claimed by the winners of Level 2
Xoie experienced communications and leakage issues on Wednesday and Thursday. A leak on Thursday afternoon caused a small fire, but the team spent the night fixing the problem, and the craft flew wonderfully on Friday., October 30th. Xoie is a lighter and more powerful version of Masten’s Level 1 vehicle, Xombie. (Wouldn’t it have been more fitting if Xombie flew the day before Halloween, though?)
Both teams met the qualifications for the Level 2 prize, but Masten had an average landing accuracy of 19 cm (7.5 in), while Armadillo Aerospace acheived an accuracy of 87 cm (34 in). This means that Masten beat out Armadillo on the very last day of the challenge by little over two feet! What an exiting space race!
Masten and Armadillo qualified for the Level 1 prizes earlier this year, with Armadillo claiming the first prize of $350,000 and Masten second place with $150,000. An awards ceremony will be held for the winning teams on November 5th.
Here’s a video of the winning flight:
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Neither company plans to rest on their laurels after these victories, though. Masten said in a press release, “We are building up a good head of steam. Next year is going to be full of bigger, faster, and higher. Winning contests is fun, but we won’t rest until we’re flying a fleet of vehicles into space carrying all sorts of commercial payloads.” They have been awared a Department of Defense Small Business Innovation and Research contract to use their vehicles in network communications testing. Masten also has a program that will fly payloads into space for $250 a kilogram.
Armadillo Aerospace has flown a vehicle in every X-Prize cup so far, and company founder John Carmack said after their Level 2 challenge flight on September 14th, “Since the Lunar Lander Challenge is quite demanding in terms of performance, with a few tweaks our Scorpius vehicle actually has the capability to travel all the way to space. We’ll be moving quickly to do higher-altitude tests, and we can go up to about 6,000 feet here at our home base in Texas before we’ll have to head to New Mexico where we can really push the envelope. We already have scientific payloads from universities lined up to fly as well, so this will be an exciting next few months for commercial spaceflight.” See our coverage on Universe Today of Armadillo’s qualifying test flight for more information and cool videos.
This is far from the last challenge that the X-Prize foundation has come up with. The Google Lunar X-Prize will award $30 million to the first privately funded team to send a robot lander to the Moon, travel 500 meters, and transmit videos and data back to the Earth. There are X-prize competitions in areas other than exploration and astronomy, including the life sciences, energy and the environment, and education and global development.
The measure of polarized light from the early Universe allowed researchers to better plot the location of matter - the left image - which later became the stars and galaxies we have today. Image Credit: Sarah Church/Walter Gear
New measurements of the cosmic microwave background (CMB) – the leftover light from the Big Bang – lend further support the Standard Cosmological Model and the existence of dark matter and dark energy, limiting the possibility of alternative models of the Universe. Researchers from Stanford University and Cardiff University produced a detailed map of the composition and structure of matter as it would have looked shortly after the Big Bang, which shows that the Universe would not look as it does today if it were made up solely of ‘normal matter’.
By measuring the way the light of the CMB is polarized, a team led by Sarah Church of the Kavli Institute for Particle Astrophysics and Cosmology at Stanford University and by Walter Gear, head of the School of Physics and Astronomy at Cardiff University in the United Kingdom were able construct a map of the way the Universe would have looked shortly after matter came into existence after the Big Bang. Their findings lend evidence to the predictions of the Standard Model in which the Universe is composed of 95% dark matter and energy, and only 5% of ordinary matter.
Polarization is a feature of light rays in which the oscillation of the light wave lies in right angles to the direction in which the light is traveling. Though most light is unpolarized, light that has interacted with matter can become polarized. The leftover light from the Big Bang – the CMB – has now cooled to a few degrees above 0 Kelvin, but it still retains the same polarization it had in the early Universe, once it had cooled enough to become transparent to light. By measuring this polarization, the researchers were able to extrapolate the location, structure, and velocity of matter in the early Universe with unprecedented precision. The gravitational collapse of large clumps of matter in the early universe creates certain resonances in the polarization that allowed the researchers to create a map of the matter composition.
Dr. Gear said, “The pattern of oscillations in the power spectra allow us to discriminate, as “real” and “dark” matter affect the position and amplitudes of the peaks in different ways. The results are also consistent with many other pieces of evidence for dark matter, such as the rotation rate of galaxies, and the distribution of galaxies in clusters.”
The measurements made by the QUaD experiment further constrain those made by previous experiments to measure properties of the CMB, such as WMAP and ACBAR. In comparison to these previous experiments, the measurements come closer to fitting what is predicted by the Standard Cosmologicl Model by more than an order of magnitude, said Dr. Gear. This is a very important step on the path to verifying whether our model of the Universe is correct.
The researchers used the QUaD experiment at the South Pole to make their observations. The QUaD telescope is a bolometer, essentially a thermometer that measures how certain types of radiation increase the temperature of the metals in the detector. The detector itself has to be near 1 degree Kelvin to eliminate noise radiation from the surrounding environment, which is why it is located at the frigid South Pole, and placed inside of a cryostat.
Paper co-author Walter Gear said in an email interview:
“The polarization is imprinted at the time the Universe becomes transparent to light, about 400,000 years after the big bang, rather than right after the big bang before matter existed. There are major efforts now to try to find what is called the “B-mode” signal” which is a more complicated polarization pattern that IS imprinted right after the big-bang. QuaD places the best current upper limit on this but is still more than an order of magnitude away in sensitivity from even optimistic predictions of what that signal might be. That is the next generation of experiments’s goal.”
The results, published in a paper titled Improved Measurements of the Temperature and Polarization of the Cosmic Microwave Background from QUaD in the November 1st Astrophysical Journal, fit the predictions of the Standard Model remarkably well, providing further evidence for the existence of dark matter and energy, and constraining alternative models of the Universe.
Source: SLAC, email interview with Dr. Walter Gear
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We regularly report on the discovery of extrasolar planets in our galaxy, but earlier this year came news of possibly the first planet discovered outside of the Milky Way. Now comes news of the potential discovery of dozens of extragalactic planetary systems. Erin Mentuch and her colleagues at the University of Toronto in Canada have analyzed 88 remote galaxies and found a broad continuum excess in the near-infrared. They conclude the most likely explanation for the 2-5 micron excess is the light from circumstellar disks, or young solar systems, forming around massive young stars. “[This] presents us with an exciting opportunity to measure the formation rate of planetary systems at cosmic epochs before our own Solar System formed,” the team writes in their paper.
The light from the galaxies studied was emitted when the universe was between a quarter and half its current age – making them far too remote for their stars to be seen individually. The galaxies’ light output peaks at two distinct wavelengths. One represents the combined light of a galaxy’s stars; the other, at longer wavelengths, comes from the glow of its interstellar dust.
In each case, the team noticed a faint third component between the two peaks. Whatever produces this light is too cold to be stars and too warm to be dust. The most likely source is circumstellar discs – embryonic solar systems around young stars. “It’s the most surprising result I’ve ever worked on,” said Roberto Abraham, one of the team members.
The opportunity to study discs that existed so long ago could help reveal how the rate of planet formation across the universe has changed over time, says Mentuch.
measurements come closer to fitting what is predicted by the Standard Cosmologicl Model by more than an order of magnitude, said Dr. Gear. This is a very important step on the path to verifying whether our model of the Universe is correct.