Ready for another Where In The Universe Challenge? Here’s #142! Take a look and see if you can name where in the Universe this image is from. Give yourself extra points if you can name the spacecraft, telescope or instrument responsible for the image. We provide the image today, but won’t reveal the answer until later. This gives you a chance to mull over the image and provide your answer/guess in the comment section. And Please, no links or extensive explanations of what you think this is — give everyone the chance to guess.
UPDATE: The answer has now been posted below!
This is a “colorized” image of Venus was taken on February 14th, 1990 by the Galileo spacecraft. It was taken from a distance of almost 1.7 million miles, about 6 days after Galileo’s closest approach to the planet. In order to be able to see the subtle contrasts in the clouds in Venus’ upper atmosphere, scientists colorized to a bluish hue, as well as to indicate that it was taken through a UV filter.
This image shows the east-to-west-trending cloud banding, and scientists estimate the winds that flow from east to west are gusting at about 230mph. The smallest features visible are about 45 miles across. Scientists point out an intriguing filimentary dark pattern is seen immediately left of the bright region at the subsolar point (equatorial “noon”). North is at the top and the evening terminator is to the left.
Lockheed Martin’s Space Operations Simulation Center in Littleton, Colorado, simulates on-orbit docking maneuvers with full-scale Orion and International Space Station mockups. The spacious center includes an 18,000 square-foot high bay area used to validate Orion’s new relative navigation system (STORRM), which will be tested on orbit during the STS-134 mission set to blast off on April19, 2011. Credit: Lockheed Martin
Lockheed Martin is aiming for a first unmanned orbital test flight of Orion as soon as 2013, said John Karas, vice president and general manager for Lockheed Martin’s Human Space Flight programs in an interview with Universe Today . The first operational flight with humans on board is now set for 2016 as stipulated in the NASA Authorization Act of 2010.
Orion manned capsule could launch in 2016 atop proposed NASA heavy lift booster from the Kennedy Space Center This Orion prototype capsule was assembled at NASA’s Michoud Assembly Facility (MAF) in New Orleans, LA and shipped by truck to Denver. At Denver, the capsule will be put through a rigorous testing program to simulate all aspects of a space mission from launch to landing and examine whether the vehicle can withstand the harsh and unforgiving environment of deep space.
Orion was originally designed to be launched by the Ares 1 booster rocket, as part of NASA’s Project Constellation Return to the Moon program, now cancelled by President Obama. The initial Orion test flight will likely be atop a Delta IV Heavy rocket, Karas told me. The first manned flight is planned for the new heavy lift rocket ordered by the US Congress to replace the Project Constellation architecture.
The goal is to produce a new, US-built manned capsule capable of launching American astronauts into space following the looming forced retirement of NASA’s Space Shuttle orbiters later this year. Thus there will be a gap of at least three years until US astronauts again can launch from US soil.
“Our nation’s next bold step in exploration could begin by 2016,” said Karas in a statement. “Orion was designed from inception to fly multiple, deep-space missions. The spacecraft is an incredibly robust, technically advanced vehicle capable of safely transporting humans to asteroids, Lagrange Points and other deep space destinations that will put us on an affordable and sustainable path to Mars.”
Jim Bray, Director, Orion Crew & Service Module, unveils the first Orion crew module to guests and media at the Lockheed Martin Space Systems Company Waterton Facility in Denver, CO. The vehicle is temporarily positioned in the composite heat shield before installation begins. Following installation of the heat shield and thermal backshell panels, the spacecraft will undergo rigorous testing to validate Orion’s ability to endure the harsh environments of deep space. Credit: Lockheed Martin
Lockheed Martin is the prime contractor for Orion under a multiyear contract awarded by NASA worth some $3.9 Billion US Dollars.
The SOSC was built at a cost of several million dollars. The 41,000 square foot facility will be used to test and validate vehicles, equipment and software for future human spaceflight programs to ensure safe, affordable and sustainable space exploration.
Mission scenarios include docking to the International Space Station, exploring the Moon, visiting an Asteroid and even journeying to Mars. Lockheed has independently proposed the exploration of several challenging deep space targets by astronauts with Orion crew vehicles which I’ll report on in upcoming features.
Orion capsule and Abort rocket mockups on display at Kennedy Space Center.
Full scale mockups of the Orion capsule and emergency abort rocket are on public display at the Kennedy Space Center Visitor Complex in Florida. Orion crew capsule mockup (at left) and Launch Abort System (LAS) at right. The emergency rocket will be bolted atop an Orion spaceship for the initial orbital test flight currently slated for 2013 launch. The LAS mockup was used in launch pad exercises at the New Mexico launch site of the LAS rocket blast-off in May 2010. Credit: Ken Kremer
The SOSC facility provides the capability for NASA and Lockheed Martin engineers to conduct full-scale motion simulations of many types of manned and robotic space missions. Demonstrations are run using laser and optically guided robotic navigation systems.
Inside the SOSC, engineers can test the performance of a vehicles ranging, rendezvous, docking, proximity operations, imaging, descent and landing systems for Earth orbiting mission as well as those to other bodies in our solar system.
“The Orion spacecraft is a state-of-the-art deep space vehicle that incorporates the technological advances in human life support systems that have accrued over the last 35 years since the Space Shuttle was designed.” says Karas. “In addition, the Orion program has recently been streamlined for additional affordability, setting new standards for reduced NASA oversight. Orion is compatible with all the potential HLLVs that are under consideration by NASA, including the use of a Delta IV heavy for early test flights.”
The Orion flight schedule starting in 2013 is however fully dependent on the level of funding which NASA receives from the Federal Government.
This past year the, Orion work was significantly slowed by large budget cuts and the future outlook is murky. Project Orion is receiving about half the funding originally planned by NASA.
And more deep cuts are in store for NASA’s budget – including both manned and unmanned projects – as both political parties wrangle about priorities as they try to pass a federal budget for this fiscal year. Until then, NASA and the entire US government are currently operating under a series of continuing resolutions passed by Congress – and the future is anything but certain.
Orion prototype crew cabin with crew hatch and windows
built at NASA Michoud Assembly Facility, New Orleans, LA. Credit: Ken KremerLockheed Martin team of aerospace engineers and technicians poses with first Orion crew cabin after welding into one piece at NASA Michoud Assembly Facility, New Orleans, LA. Credit: Ken KremerOrion and ISS simulated docking
If you think you’re looking a a star studded field, you’d be right. But take a close look at the full size image done by Joe Brimacombe and you’ll see a faint circle with the latest of sky phenomena in its center – Nova Sagitarii 2011… #2!
According to the latest AAVSO press release done by Elizabeth Waagen, “We have been informed by the Central Bureau for Astronomical Telegrams (Central Bureau Electronic Telegram 2679, Daniel W. E. Green, ed.) that Koichi Nishiyama, Kurume, Japan, and Fujio Kabashima, Miyaki, Japan, report their discovery of a possible nova at magnitude 11.7 on two unfiltered CCD frames taken around March 27.832 UT. They confirmed the object on images taken on March 27.832 UT. After posting on the Central Bureau’s Transient Objects Confirmation Page (TOCP) webpage, the object was given the provisional name PNV J18102135-2305306.
Low resolution spectra taken March 28.725 UT by A. Arai, M. Nagashima, T. Kajikawa, and C. Naka, Koyama Astronomical Observatory, Kyoto Sangyo University, suggest that N Sgr 2011 No. 2 is a classical nova that is reddened by interstellar matter.”
At magnitude 12.5, one tiny star is hard to pick out of a huge field, especially when it’s so close to our galactic center. As Joe said, “It is quite close to the Cat’s Paw and Lagoon Nebulae, so the wide field image is neat even though its only a single 10 minute exposure.” For those of us who would take more than ten minutes just to find it, the celestial coordinates are: R.A. 18:10:21.35 Dec. -23:05:30.6. N Sgr 2011 No. 2 has been entered into VSX and assigned the identifier VSX J181021.3-230530. Finder charts for N Sgr 2011 No. 2 may be plotted by entering the coordinates above in the International Variable Star
Plotter. Please report observations to the AAVSO International Database
as N SGR 2011 NO. 2.
It might be an early morning adventure, but then… Aren’t the skies always the darkest just before dawn?
Smooth plains on Mercury's northern hemisphere. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
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Sharing just a few of the 1,500 images the MESSENGER spacecraft has now taken from its orbital vantage point, mission scientists are understandably excited – if not overwhelmed – by the data being returned from Mercury. “The instruments are all working marvelously and returning data,” said MESSENGER Principal Investigator Sean Solomon. “The imaging system was turned on earlier this week and over 1,500 images will be acquired over a 3 day period. That is more images than were taken during any of the flybys by the spacecraft.”
Solomon said some of the first images were taken precisely 37 years after the first spacecraft flew by Mercury, Mariner 10 in 1974. “We have now closed the loop begun by Mariner 10, culminating with the first insertion of a spacecraft in orbit.”
2,430 days ago the MESSENGER lifted off from Earth, and after three flybys and a nearly 5 billion mile journey, the spacecraft’s thrusters fired for 15 minutes back on March 17, enabling the spacecraft to ease into orbit.
While already finding intriguing features – many which pose more questions than answers, Solomon reminded reporters during a press conference call today that “all the big questions about Mercury are meant to be answered in a year of observations, not just a couple of days, so we’ll look forward to what is yet to come.”
The top image shows an area of Mercury’s north polar region, revealing terrain that had not been previously seen by spacecraft. The long shadows also accentuate the topography of the surface, which includes a number of ridges, but an unusually smooth surface. Solomon said understanding the interiors of the craters in Mercury’s polar regions and any ices they may contain is one of the main science goals of the MESSENGER mission. “Radar images of Mercury that are now 20 years old suggested that water ice could be in the interiors of these craters,” Solomon said. “That is a hypothesis we’ve been aching to test for 20 years, and now we’ll be able to peer into those crater floors.”
This WAC image showing a never-before-imaged area of Mercury’s surface was taken from an altitude of ~450 km (280 miles) above Mercury. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
This is another region never seen before by spacecraft. “This is probably a plain deposit formed by undulating ridges and a host of secondary craters formed when a large crater was formed out of the field of view,” Solomon said. “We’re seeing that secondary craters (those formed from the ejecta of another crater) are very pervasive across the surface.”
Solomon added that they are seeing secondary craters that are larger than most secondary craters, compared to those on the Moon and other planetary bodies. “They are surprisingly large,” he said. “ A lot of questions raised by images taken so far and have a large menu of questions we’ll be pursuing over the mission.”
Beautiful bright crater on Mercury. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
The crater near the bottom of this image is a beautiful example of a relatively small, simple, fresh impact feature on Mercury.The bright ejecta and rays are symmetrically distributed around the crater, indicating that the body that struck Mercury to form the crater approached on a path that was not highly inclined from the vertical.
MESSENGER Systems engineer Eric Finnegan told reporters that it takes about 6 minutes for data to be relayed from the spacecraft to Earth, as Mercury (and the spacecraft) is about .71 AU away, the equivalent of about 106 million km (66 million miles). MESSENGER is in an elliptical orbit, and at its closest point in orbit (periapsis) is about 250 km away from Mercury, and at its farthest point (apoapsis) is about 1,500 km away.
Wide Angle Camera color image of Mercury. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
This is one of the first color images from MESSENGER in orbit. Solomon said the Wide Angle Camera is not a typical color camera. It can image in 11 colors, ranging from 430 to 1020 nm wavelength (visible through near-infrared). “We will be taking global images in at least 8 filters to get a sense of the color variation, which shows the variations in composition and depth of surface features exposed by the action of impact cratering from Mercury’s history.”
From Orbit, Looking toward Mercury's Horizon. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
Images like this were frequently seen during MESSENGER’s three flybys. But now that the spacecraft is in orbit of Mercury, views of Mercury’s horizon in the images will be much less common. Occasionally, however, in order to obtain images of a certain portion of Mercury’s surface, the horizon will also be visible. But Solomon said MESSENGER’s goal is to get a set of global data for the planet. “An entire global perspective is unfolding and will continue to unfold over next few months,” he said.
Bright rays, consisting of impact ejecta and secondary craters, spread across this NAC image and radiate from Debussy crater, located at the top. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
This is a closeup Debussy Crater, which was the object of the first image released by MESSENGER yesterday. When asked about the age of this crater, Solomon said it is difficult to give a hard age to craters on Mercury due to not having samples in hand, like to do for the Moon. “On the moon ones that are bright like this, such as Copernicus, were formed in the last 20% in the history of the planet. We see only a handful of bright craters like Debussy on Mercury.”
“When you see a crater that is so bright,” Solomon continued, “ it is because it has not gone through the process of space weathering, completely. Brightness of craters identifies them as being younger than the rest of the terrain, as it hasn’t had the time to have their characteristics altered by age, as those of us with gray hair know.”
Solomon said Debussy was likely created by in impact of an object 5-10 km across.
“Orbits of most asteroids and comets that encounter Mercury are traveling at a much higher speed than planetary bodies farther out from the Sun, and that shows in the amount of melt shown in the surface of Mercury. But still a lot we have to learn about that. Craters at different states of decay and degradation will tell us more about this.”
Altimetric profiles obtained on 29 March during the first two successive MESSENGER orbits on which the Mercury Laser Altimeter (MLA) instrument was operating. Credit: NASA/Goddard Space Flight Center/MIT/Johns Hopkins University Applied Physics Laboratory
This graph shows the first two topographic profiles that were obtained from orbit by the Mercury Laser Altimeter (MLA). “This shows rich detail that we’ve just begun to analyze,” Solomon said, “showing exquisite detail, and we’ll be able to see the topography at both scales of individual geological features and global regions.”
This plot depicts measurements of the strength of Mercury's internal magnetic field measured on 10 successive MESSENGER orbits. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
One big question is about Mercury’s magnetic field. This illustrates the measurements made from 10 orbits of MESSENGER’s magnetometer. In a span of 5 days, messenger has tripled the mount of observations of the planet’s magnetic field, so Solomon said the science team is quickly ramping up a much larger data set to see the geometry of Mercury’s magnetic field, which might help explain why the solar system’s smallest planet still has a magnetic field when the larger planets Mars and Venus do not.
Moreover, because of MESSENGER’s orbit, the maximum magnitude of the measured field was greater than that seen during any of the spacecraft flybys. Solomon said these observations are improving our understanding of Mercury’s magnetic field and how its magnetosphere can change over timescales of minutes, how the solar activity and interaction between the Sun and the planet affect the magnetic field.
“As the Sun’s activity ramps up, it is an exciting time to be at Mercury and have a ringside perspective,” Solomon said.
Based on results from the first year of the Kepler mission, researchers have learned a way to distinguish two different groups of red giant stars: the giants, and the truly giant giants. The findings appear this week in Nature.
Red giants, having exhausted the supply of hydrogen in their cores, burn hydrogen in a surrounding shell. Once a red giant is sufficiently evolved, the helium in the core also undergoes fusion. Until now, the very different stages looked roughly the same.
Lead author Timothy Bedding, from the University of Sydney in Australia, and his colleagues used high-precision photometry obtained by the Kepler spacecraft over
more than a year to measure oscillations in several hundred red giants.
Using a technique called asteroseismology, the researchers were able to place the stars into two clear groups, “allowing us to distinguish unambiguously between hydrogen-shell-burning stars (period spacing mostly 50 seconds) and those that are also burning helium (period spacing 100 to 300 seconds),” they write. The latter population lend to the star an oscillation pattern dominated by gravity-mode period spacings.
In a related News and Views article, Travis Metcalfe of the Boulder, Colo.-based National Center for Atmospheric Research explains that like the sun, “the surface of a red giant seems to boil as convection brings heat up from the interior and radiates it into the coldness of outer space. These turbulent motions act like continuous starquakes, creating sound waves that travel down through the interior and back to the surface.” Some of the sounds, he writes, have just the right tone — a million times lower than what people can hear — to set up standing waves known as oscillations that cause the entire star to change its brightness regularly over hours and days, depending on its size. Asteroseismology is a method to measure those oscillations.
Metcalfe goes on to explain that a red giant’s life story depends not only on its age but also on its mass, with stars smaller than about twice the mass of the sun undergoing a sudden ignition called a helium flash.
“In more massive stars, the transition to helium core burning is gradual, so the stars exhibit a wider range of core sizes and never experience a helium flash. Bedding and colleagues show how these two populations can be distinguished observationally using their oscillation modes, providing new data to validate a previously untested prediction of stellar evolution theory,” he writes.
The study authors conclude that their new measurement of gravity-mode period spacings “is an extremely reliable parameter for distinguishing between stars in these two evolutionary stages, which are known to have very different core densities but are otherwise very similar in their fundamental properties (mass, luminosity and radius). We note that other asteroseismic observables, such as the small p-mode separations, are not able to do this.”
Russia's Elektro-L spacecraft captured this view of the Moon over the Red Sea region of the Earth. Credit: NPO Lavochkin
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This stunning picture of the Moon and Earth was taken by Russia’s new Elektro-L spacecraft, a weather-forecasting satellite that launched in January 2011. This is the first major spacecraft developed in post-Soviet Russia, and it is designed to give Russian meteorologists the ability to watch the entire disk of the planet, thanks to the satellite’s position in the geostationary orbit 36,000 kilometers above the equator. The clarity of the images is fantastic, as you can see in another image of just the Earth, below. The Elektro-L is designed to last at least a decade, and will enable local and global weather forecasting, analysis of oceanic conditions, as well as space weather monitoring, such as measurements of solar radiation, properties of Earth’s ionosphere and magnetic field.
On Feb. 26, 2011, at 14:30 Moscow Time, the Elektro-L satellite produced its first breathtaking image of the home planet. Credit: NPO Lavochkin
Star cluster and surrounding nebula NGC 371. Credit: ESO/Manu Mejias
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Just in time for the start of spring, the ESO’s Very Large Telescope has captured this stunning new image of a region of glowing hydrogen surrounding the star cluster NGC 371.
Regions of ionized hydrogen like this one — known as HII regions — are exploding with the births of new stars. NGC 371 lies in our neighboring galaxy, the Small Magellanic Cloud. It’s an example of an open cluster; its stars all originate from the same diffuse HII region, and over time the majority of the hydrogen is used up by star formation — leaving behind a shell of hydrogen such as the one in this image, along with a cluster of hot young stars.
NGC 371 in the constellation of Tucana (The Toucan). Through a moderate-sized amateur telescope this cluster appears quite large, but dim, and the gas cloud is difficult to see. Credit: ESO, IAU and Sky & Telescope
The Small Magellanic Cloud is a dwarf galaxy just 200,000 light-years away, which makes it one of the closest galaxies to the Milky Way. It contains stars at all stages of their evolution, from the highly luminous young stars found in NGC 371 to supernova remnants of dead stars. These energetic youngsters emit copious amounts of ultraviolet radiation causing surrounding gas, such as leftover hydrogen from their parent nebula, to light up with a colorful glow that extends for hundreds of light-years in every direction.
Open clusters are common; there are numerous examples in our own Milky Way. However, NGC 371 is of particular interest due to the unexpectedly large population of variable stars — stars that change in brightness over time. A particularly interesting type of variable star, known as slowly pulsating B stars, can also be used to study the interior of stars through asteroseismology, and several of these have been confirmed in this cluster. Asteroseismology is the study of the internal structure of pulsating stars by looking at the different frequencies at which they oscillate.
Variable stars play a pivotal role in astronomy: some types are invaluable for determining distances to far-off galaxies and the age of the Universe.
The data for this image were selected from the ESO archive by Manu Mejias as part of the Hidden Treasures competition, which invited amateur astronomer to search through ESO’s archives in hopes of finding a well-hidden gem. Three of Mejias’s images made the top 20. His picture of NGC 371 was ranked sixth in the competition.
Astronauts Steve Bowen and Alvin drew work in tandem on one of the truss sections of the ISS during the first spacewalk of the STS-133 mission. Credit: NAS
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About 100 tons of meteoroids bombard the Earth’s atmosphere every day. For spacecraft in Earth orbit, a collision with these particles could cause serious damage or catastrophic failure, and a hit on an astronaut or cosmonaut conducting extra-vehicular activities in space would be life-threatening, if not fatal. But before anyone steps outside the space shuttle or the International Space Station, NASA checks with data from Canadian Meteor Orbit Radar to determine if it’s safe.
The CMOR system consists of three identical radar systems slaved together to transmit and receive simultaneously. Credit: University of Western Ontario
Using a series of ‘smart cameras’, a one-of-a-kind triple-frequency radar system and computer modeling, CMOR provides real-time data, tracking a representative sample of the meteoroids around and approaching Earth, which are traveling at hypervelocity speeds averaging 10 km/s (22,000 mph).
The system is based at based at The University of Western Ontario.
“When it’s in orbit, the largest danger posed to the space shuttle is impact from orbital debris and meteoroids,” said Peter Brown, Western physics and astronomy professor. By knowing when meteoroid activity is high, NASA can make operational changes such as shielding vulnerable areas of the shuttle or deferring space walks so astronauts remain protected.
Brown told Universe Today that the meteoroids tracked by the system are from 0.1mm and larger, and it detects the ionization trails left by these meteoroids and not the solid particles themselves.
CMOR records about 2,500 meteoroid orbits per day by using a multi-frequency HF/VHF radar. The radar produces data on the range, angle of arrival, and velocity/orbit in some instances. In operation since 1999, the system has measured 4 million individual orbits, as of 2009.
NASA makes daily decisions based on the data from this system. Radio waves are bounced off the ionization trails of meteors by the radar, allowing the system to provide the data necessary to understand meteoric activity on a given day. “From this information we can figure out how many meteoroids are hitting the atmosphere, as well as the direction they’re coming from and their velocity,” Brown said.
NASA says the greatest challenge is medium size particles (objects with a diameter between 1 cm to 10 cm), because of how difficult they are to track, and they are large enough to cause catastrophic damage to spacecraft and satellites. Small particles less than 1 cm pose less of a catastrophic threat, but they do cause surface abrasions and microscopic holes to spacecraft and satellites.
STS-35 Space Shuttle window pit from orbital debris impact. Credit: NASA
But the radar information from the Canadian system can also be combined with optical data to provide broader information about the space environment and produce models useful during the construction of satellites. Scientists are better able to shield or protect the satellites to minimize the effect of meteoroid impacts before sending them into space.
The ISS is the most heavily shielded spacecraft ever flown, and uses “multishock” shielding, which uses several layers of lightweight ceramic fabric to act as “bumpers,” which shocks a projectile to such high energy levels that it melts or vaporizes and absorbs debris before it can penetrate a spacecraft’s walls. This shielding protects critical components such as habitable compartments and high-pressure tanks from the nominal threat of particles approximately 1 cm in diameter. The ISS also has the capability of maneuvering to avoid larger tracked objects.
The original radar system was developed for measuring winds in the Earth’s upper atmosphere, and has since been modified by Brown and his fellow researchers to be optimized for the kinds of astronomical measurements currently being used by NASA.
When the radar detects meteors, the software analyzes the data, summarizes it and sends it to NASA electronically. Brown’s role is to keep the process running and continue to develop the techniques used to obtain the information over time.
Western has been working co-operatively with NASA for 15 years, and has been involved with its Meteor Environment Office (MEO) since it was created in 2004. The role of the MEO is predominantly to evaluate risk. “Everyone knows that rocks fly through space,” says MEO head Bill Cooke. “Our job is to help NASA programs, like the space station, figure out the risk to their equipment, educate them on the environment and give them models to evaluate the risks posed to spacecrafts and astronauts.”
MESSENGER's first image from Mercury orbit, with the bright Debussy crater visible at upper right. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
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Here it is, the first image taken by the MESSENGER spacecraft since entering orbit around Mercury on March 17, and it includes portions of the planet not yet previously seen by spacecraft. The image was taken on today, March 29, 2011 at 5:20 am EDT by the Mercury Dual Imaging System as the spacecraft sailed high above Mercury’s south pole. The dominant rayed crater in the upper portion of the image is Debussy, and the smaller crater Matabei with unusual dark rays is visible to the west of Debussy. The bottom portion of this image near Mercury’s south pole is new territory, with MESSENGER being the first spacecraft to image this region of Mercury.
After capturing its first image, MESSENGER acquired an additional 363 images during six hours before downlinking some of the data to Earth. The MESSENGER team is currently looking over the newly returned data, which are still continuing to come down.
The image was acquired as part of the orbital commissioning phase of the MESSENGER mission. Over the next three days, the spacecraft will acquire 1,185 additional images in support of MDIS commissioning-phase activities. Continuous global mapping of Mercury will begin on April 4.
“The entire MESSENGER team is thrilled that spacecraft and instrument checkout has been proceeding according to plan,” says MESSENGER Principal Investigator Sean Solomon, of the Carnegie Institution of Washington. “The first images from orbit and the first measurements from MESSENGER’s other payload instruments are only the opening trickle of the flood of new information that we can expect over the coming year. The orbital exploration of the Solar System’s innermost planet has begun.”
Several other images will be released tomorrow, March 30, in conjunction with a media teleconference. We’ll get them posted as quickly as possible!
A1689-zD1, one of the brightest and most distant galaxies, is 12.8 billion light years away - an extremely far distance in our expanding universe. Image credit: NASA/ESA/JPL-Caltech/STScI
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Welcome back to the third, and last, installment of Cosmology 101. So far, we’ve covered the history of the universe up to the present moment. But what happens next? How will our universe end? And how can we be so sure that this is how the story unfolded?
Robert Frost once wrote, “Some say the world will end in fire; some say in ice.” Likewise, some scientists have postulated that the universe could die either a dramatic, cataclysmic death – either a “Big Rip” or a “Big Crunch” – or a slower, more gradual “Big Freeze.” The ultimate fate of our cosmos has a lot to do with its shape. If the universe were open, like a saddle, and the energy density of dark energy increased without bound, the expansion rate of the cosmos would eventually become so great that even atoms would be torn apart – a Big Rip. Conversely, if the universe were closed, like a sphere, and gravity’s strength trumped the influence of dark energy, the outward expansion of the cosmos would eventually come to a halt and reverse, collapsing on itself in a Big Crunch.
Despite the poetic beauty of fire, however, current observations favor an icy end to our universe – a Big Freeze. Scientists believe that we live in a spatially flat universe whose expansion is accelerating due to the presence of dark energy; however, the total energy density of the cosmos is most likely less than or equal to the so-called “critical density,” so there will be no Big Rip. Instead, the contents of the universe will eventually drift prohibitively far away from each other and heat and energy exchange will cease. The cosmos will have reached a state of maximum entropy, and no life will be able to survive. Depressing and a bit anti-climactic? Perhaps. But it probably won’t be perceptible until the universe is at least twice its current age.
At this point you might be screaming, “How do we know all this? Isn’t it all just rampant speculation?” Well, first of all, we know without a doubt that the universe is expanding. Astronomical observations consistently demonstrate that light from distant stars is always redshifted relative to us; that is, its wavelength has been stretched due to the expansion of the cosmos. This leads to two possibilities when you wind back the clock: either the expanding universe has always existed and is infinite in age, or it began expanding from a smaller version of itself at a specific time in the past and thus has a fixed age. For a long time, proponents of the Steady State Theory endorsed the former explanation. It wasn’t until Arno Penzias and Robert Wilson discovered the cosmic microwave background in 1965 that the big bang theory became the most accepted explanation for the origin of the universe.
Why? Something as large as our cosmos takes quite a while to cool completely. If the universe did, in fact, began with the kind of blistering energies that the big bang theory predicts, astronomers should still see some leftover heat today. And they do: a uniform 3K glow evenly dispersed at every point in the sky. Not only that – but WMAP and other satellites have observed tiny inhomogeneities in the CMB that precisely match the initial spectrum of quantum fluctuations predicted by the big bang theory.
What else? Take a look at the relative abundances of light elements in the universe. Remember that during the first few minutes of the cosmos’ young life, the ambient temperature was high enough for nuclear fusion to occur. The laws of thermodynamics and the relative density of baryons (i.e. protons and neutrons) together determine exactly how much deuterium (heavy hydrogen), helium and lithium could be formed at this time. As it turns out, there is far more helium (25%!) in our current universe than could be created by nucleosynthesis in the center of stars. Meanwhile, a hot early universe – like the one postulated by the big bang theory – gives rise to the exact proportions of light elements that scientists observe in the universe today.
But wait, there’s more. The distribution of large-scale structure in the universe can be mapped extremely well based solely on observed anisotropies in the CMB. Moreover, today’s large-scale structure looks very different from that at high redshift, implying a dynamic and evolving universe. Additionally, the age of the oldest stars appears to be consistent with the age of the cosmos given by the big bang theory. Like any theory, it has its weaknesses – for instance, the horizon problem or the flatness problem or the problems of dark energy and dark matter; but overall, astronomical observations match the predictions of the big bang theory far more closely than any rival idea. Until that changes, it seems as though the big bang theory is here to stay.
