May 27, 2015
The new images, taken May 8-12 using a powerful telescopic camera and down-linked last week, reveal more detail about Pluto’s complex and high contrast surface.
May 27, 2015
The new images, taken May 8-12 using a powerful telescopic camera and down-linked last week, reveal more detail about Pluto’s complex and high contrast surface.
Images of Comet 67P/Churyumov-Gerasimenko taken from the Rosetta spacecraft:
The comet’s activity has been significantly increasing over the last weeks and months.
As the comet moves closer to the Sun along its orbit, its nucleus gets warmer and warmer. Frozen gases sublimate from its surface, carrying dust particles with it and enshrouding the nucleus in a dense coma.
With only four months to go until perihelion – the closest point to the Sun – this process is well underway, with pronounced dust jets seen at all times on the comet’s day side.
Montage of images:
Visit the site below for more information and remarkable images.
Praying one day as I read an APOD (NASA’s Astronomy Picture of the Day) about black holes, I asked the Lord a question. What are they for? “Trash compactors,” he replied. Hmmm. Here’s an APOD about our own Milky Way and it’s black hole, Sag-A*.
APOD 2012 November 2
Image Credit: NASA, JPL-Caltech, NuSTAR project
At the center of our Milky Way Galaxy, a mere 27,000 light-years away, lies a black hole with 4 million times the mass of the Sun. Fondly known as Sagittarius A* (pronounced A-star), the Milky Way’s black hole is fortunately mild-mannered compared to the central black holes in distant active galaxies, much more calmly consuming material around it. From time to time it does flare-up, though.
An outburst lasting several hours is captured in this series of premier X-ray images from the orbiting Nuclear Spectroscopic Telescope Array (NuSTAR). Launched last June 13 (2011), NuSTAR is the first to provide focused views of the area surrounding Sgr A* at X-ray energies higher than those accessible to Chandra and XMM observatories.
Spanning two days of NuSTAR observations, the flare sequence is illustrated in the panels at the far right. X-rays are generated in material heated to over 100 million degrees Celsius, accelerated to nearly the speed of light as it falls into the Miky Way’s central black hole.
The main inset X-ray image spans about 100 light-years. In it, the bright white region represents the hottest material closest to the black hole, while the pinkish cloud likely belongs to a nearby supernova remnant.
The 100-kilogram Rosetta lander is provided by a European consortium under the leadership of the German Aerospace Research Institute (DLR). Other members of the consortium are ESA and institutes from Austria, Finland, France, Hungary, Ireland, Italy and the UK.
The box-shaped lander is carried on the side of the orbiter until it arrives at Comet 67P/Churyumov-Gerasimenko.
Once the orbiter is aligned correctly, the lander is commanded to self-eject from the main spacecraft and unfold its three legs, ready for a gentle touchdown at the end of the ballistic descent.
On landing, the legs damp out most of the kinetic energy to reduce the chance of bouncing, and they can rotate, lift or tilt to return the lander to an upright position.
Immediately after touchdown, a harpoon is fired to anchor the lander to the ground and prevent it escaping from the comet’s extremely weak gravity. The minimum mission target is one week, but surface operations may continue for many months.
The lander structure consists of a baseplate, an instrument platform, and a polygonal sandwich construction, all made of carbon fibre. Some of the instruments and subsystems are beneath a hood that is covered with solar cells.
An antenna transmits data from the surface to Earth via the orbiter. The lander carries nine experiments, with a total mass of about 21 kilograms. It also carries a drilling system to take samples of subsurface material.
ESA confirms the primary landing site for Rosetta
15 October 2014
ESA has given the green light for its Rosetta mission to deliver its lander, Philae, to the primary site on 67P/Churyumov–Gerasimenko on 12 November, in the first-ever attempt at a soft touchdown on a comet.
Philae’s landing site, currently known as Site J and located on the smaller of the comet’s two ‘lobes’, was confirmed on 14 October following a comprehensive readiness review.
Since the arrival, the mission has been conducting an unprecedented survey and scientific analysis of the comet, a remnant of the early phases of the Solar System’s 4.6 billion-year history.
At the same time, Rosetta has been moving closer to the comet: starting at 100 km on 6 August, it is now just 10 km from the centre of the 4 km-wide body. This allowed a more detailed look at the primary and backup landing sites in order to complete a hazard assessment, including a detailed boulder census.
The decision that the mission is ‘Go’ for Site J also confirms the timeline of events leading up to the landing.
Rosetta will release Philae at 08:35 GMT/09:35 CET on 12 November at a distance of approximately 22.5 km from the centre of the comet. Landing will be about seven hours later at around 15:30 GMT/16:30 CET.
With a one-way signal travel time between Rosetta and Earth on 12 November of 28 minutes 20 seconds, that means that confirmation of separation will arrive on Earth ground stations at 09:03 GMT/10:03 CET and of touchdown at around 16:00 GMT/17:00 CET.
A short manoeuvre must then take place around two hours before separation. This will set Rosetta on course to release Philae on the right trajectory to land on the comet. The final critical Go/No-Go for separation occurs shortly after this manoeuvre.
After the release of Philae, Rosetta will manoeuvre up and away from the comet, before reorienting itself in order to establish communications with Philae. All being well, Rosetta and its lander will begin communications about two hours after separation.
During the seven-hour descent, Philae will take images and conduct science experiments, sampling the dust, gas and plasma environment close to the comet.
It will take a ‘farewell’ image of the Rosetta orbiter shortly after separation, along with a number of images as it approaches the comet surface. It is expected that the first images from this sequence will be received on Earth several hours after separation.
Once safely on the surface, Philae will take a panorama of its surroundings. Again, this is expected back on Earth several hours later.
The first sequence of surface science experiments will begin about an hour after touchdown and will last for 64 hours, constrained by the lander’s primary battery lifetime.
Longer-term study of the comet by Philae will depend on for how long and how well the batteries are able to recharge, which in turn is related to the amount of dust that settles on its solar panels.
In any case, it is expected that by March 2015, as the comet moves closer in its orbit towards the Sun, temperatures inside the lander will have reached levels too high to continue operations, and Philae’s science mission will come to an end.
The Rosetta orbiter’s mission will continue for much longer. It will accompany the comet as it grows in activity until their closest approach to the Sun in August 2015 and then as they head back towards the outer Solar System.
This unprecedented mission will study how a comet evolves and give important insights into the formation of our Solar System, and the origins of water and perhaps even life on Earth.
ESA – European Space Agency
Cometwatch – 28 October
This four-image NAVCAM montage comprises images taken on 28 October – shortly before moving to the pre-lander delivery orbit – from a distance of 9.7 km from the centre of comet 67P/C-G, or roughly 7.7 km from the surface.
The corresponding image scale is about 65 cm/pixel, so each 1024 x 1024 pixel frame is about 665 m across. The montage has been slightly tweaked and the central vignetting reduced. The four original frames are provided at the end of the post.
The montage nicely ‘joins the dots’ with the region presented in the 8 October montage.
Given the peculiar low-density, low-gravity nature of a comet, it is perhaps dangerous to make direct analogies with Earth-like features and processes. But until we have the science team’s analysis of what they think is actually happening on this comet, analogies might nevertheless still provide a useful way of trying to decipher what we are seeing.
In a number of places in this region, there is an impression that the prevalent dusty material covering the surface is not particularly stable and that it occasionally gives way, perhaps in a similar way that snow on a mountain side may become dislodged, giving rise to an avalanche or, alternatively, a rockfall or landslide.
For example, look in the lower third of the top left image. There you’ll see what looks like a crack close to the edge of the cliff, suggesting that this portion might eventually collapse, similar to the way a snow cornice on a mountain ridge peels away. This feature is also visible in the 8 October image.
Another example can be seen in the lower right corner of the bottom right image, where material appears to have slid over the edge of a cliff.
On Earth, avalanches are typically triggered by an increased load, leading to the mechanical failure of a slab of material under gravity, or due to melting snow as a result of increased solar radiation. On a comet, presumably the latter process is more likely to occur, with sublimation-based erosion acting to weaken the surface material, resulting in a collapse.
Comet 67P on Aug. 3, 2014. ESA’s Rosetta probe snapped this image of its target, Comet 67P on Aug. 3, 2014 from a distance of 177 miles (285 kilometers). Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
I’ve been following the progress of the ESA Rosetta spacecraft recently as it neared Comet 67P/Churyumov-Gerasimenko.
After a ten-year journey, today it arrived!
Here’s a link to the ESA live broadcast this morning. http://www.space.com/17933-nasa-television-webcasts-live-space-tv.html
More about Rosetta and the comet from Space.com online today:
Europe’s Rosetta Spacecraft Makes Historic Arrival at Comet
By Miriam Kramer, Staff Writer | August 06, 2014 06:00am ET
After a decade in space and 4 billion miles, Europe’s Rosetta spacecraft has made history: For the first time ever, a robotic probe from Earth is flying with a comet and will soon enter orbit.
The European Space Agency’s Rosetta spacecraft arrived at its target, Comet 67P/Churyumov-Gerasimenko, today (Aug. 6) to end a 10-year journey across the solar system. The spacecraft performed an engine burn that brought it about 62 miles (100 kilometers) from the comet’s surface.
Comet 67P/C-G and Rosetta are now flying about 251 million miles (450 million kilometers) from Earth. Engineers on the ground had to program the probe to go through a series of complicated burns and maneuvers to make the spacecraft’s rendezvous with the comet a possibility.
“This is the end of 10 years of interplanetary flight,” Rosetta Flight Director Andrea Accomazzo said during ESA’s live comet rendezvous webcast Wednesday.
Applause broke out in Rosetta’s mission control center in Darmstadt, Germany, where a crowd of ESA dignitaries and officials had gathered to watch the historic event.
“We’re at the comet! Yes!” exclaimed Sylvain Lodiot, Rosetta’s spacecraft operations manager, once the probe’s successful arrival at Comet 67P/C-G was confirmed.
Rosetta is expected to stay in orbit around Comet 67P/C-G until the end of 2015. “We’re going to going to ride along with this comet. We’re going to have a ringside seat,” Matt Taylor, ESA Rosetta project scientist, said Wednesday as the spacecraft arrived at Comet 67P/C-G. “It’s going to be an awesome ride. Stay tuned.”
Link to entire article: http://www.space.com/26740-rosetta-spacecraft-comet-arrival.html
Close neighbor of the Sun and the coldest of its kind
25 April 2014
“It is very exciting to discover a new neighbor of our solar system that is so close,” said Kevin Luhman, an associate professor of astronomy and astrophysics at Penn State and a researcher in the Penn State Center for Exoplanets and Habitable Worlds. “In addition, its extreme temperature should tell us a lot about the atmospheres of planets, which often have similarly cold temperatures.”
Brown dwarfs start their lives like stars, as collapsing balls of gas, but they lack the mass to burn nuclear fuel and radiate starlight. The newfound coldest brown dwarf, named WISE J085510.83-071442.5, has a chilly temperature between minus 54 and 9 degrees Fahrenheit (minus 48 to minus 13 degrees Celsius). Previous record holders for coldest brown dwarfs, also found by WISE and Spitzer, were about room temperature.
Although it is very close to our solar system, WISE J085510.83-071442.5 is not an appealing destination for human space travel in the distant future. “Any planets that might orbit it would be much too cold to support life as we know it” Luhman said.
“This object appeared to move really fast in the WISE data,” said Luhman. “That told us it was something special.” The closer a body, the more it appears to move in images taken months apart. Airplanes are a good example of this effect: a closer, low-flying plane will appear to fly overhead more rapidly than a high-flying one.
WISE was able to spot the rare object because it surveyed the entire sky twice in infrared light, observing some areas up to three times. Cool objects like brown dwarfs can be invisible when viewed by visible-light telescopes, but their thermal glow — even if feeble — stands out in infrared light.
After noticing the fast motion of WISE J085510.83-071442.5 in March, 2013, Luhman spent time analyzing additional images taken with Spitzer and the Gemini South telescope on Cerro Pachon in Chile. Spitzer’s infrared observations helped to determine the frosty temperature of the brown dwarf.
WISE J085510.83-071442.5 is estimated to be 3 to 10 times the mass of Jupiter. With such a low mass, it could be a gas giant similar to Jupiter that was ejected from its star system. But scientists estimate it is probably a brown dwarf rather than a planet since brown dwarfs are known to be fairly common. If so, it is one of the least massive brown dwarfs known.
Combined detections from WISE and Spitzer, taken from different positions around the Sun, enabled the measurement of its distance through the parallax effect. This is the same principle that explains why your finger, when held out right in front of you, appears to jump from side to side when you alternate left-eye and right-eye views.
In March of 2013, Luhman’s analysis of the images from WISE uncovered a pair of much warmer brown dwarfs at a distance of 6.5 light years, making that system the third closest to the Sun. His search for rapidly moving bodies also demonstrated that the outer solar system probably does not contain a large, undiscovered planet, which has been referred to as “Planet X” or “Nemesis.”
“It is remarkable that even after many decades of studying the sky, we still do not have a complete inventory of the Sun’s nearest neighbors,” said Michael Werner, the project scientist for Spitzer at NASA’s Jet Propulsion Laboratory (JPL), which manages and operates Spitzer. “This exciting new result demonstrates the power of exploring the universe using new tools, such as the infrared eyes of WISE and Spitzer.”
The Watchers online
10 Feb 2014
Might there be more than one universe? If so, we need to rethink our notions of the cosmos.
For two weeks every summer, my parents rented a holiday apartment by the beach in Vlora, an old coastal town along the Adriatic. It was known as Aulona in Greek and Roman times, and was a special place to visit even during 1980s communist Albania. Aulona’s spirit, imprinted on the traditions, superstitions, and landscape of the place, floats outside of time. The town is guarded by a rugged terrain of high mountains, turquoise waters, and black rocks, which blend into silence at sunset. It is a place to dream absurd dreams.
My favorite evening activity was to sit on the deserted sand alone. I watched waves linger at the soundless horizon before breaking rhythmically onto the shore. As night fell, I waited until the line dividing sky and sea blurred away and all boundaries vanished. Of course everybody knew that the world beyond the horizon was strictly forbidden to those of us behind the Iron Curtain. But, sitting in the dark, I was free to imagine. Were kids on the other side of the Adriatic equally enchanted by the edge of the sky we shared? Eventually my dad would come over and, without reprimand, sit on the sand next to me. Then it was the two of us in a hushed conversation with the sky. Before long, he would speak, telling me it was time to leave, and the gentle spell of the sea and the sky would break.
Twenty years later, in 2009, I sat with a few dozen other scientists in a room at the Kavli Institute for Cosmology at the University of Cambridge to watch the launch of the Planck satellite. A muffled buzz filled the room with cautious excitement. Casual conversation would be interrupted by concern over pauses in the live transmission. When the countdown began, the room fell eerily quiet, and with lift-off came deep cheers and loud applause.
Planck was on its way to measure the gentle glow of light left over from the fiery birth of our universe, called the Cosmic Microwave Background (CMB). The CMB is a detailed fingerprint that allows us to cast our gaze onto the first few moments of our universe’s existence, and to cast light onto some very ancient questions: where are we from, and how did we get here? (see The Standard Model)
Four years into its mission, the Planck collaboration released the most finely detailed map of the CMB ever measured. In its details was a bombshell: anomalies in the distribution of the CMB brightness that could not be the result of anything in our own universe. Here was an empirically observed hidden code pointing to a rich and vast cosmos, in which our own universe is but one humble member. The limits of our range of exploration had suddenly grown immensely. We were at the shore of the multiverse.
Contemplating the existence of other universes is not a new endeavour. From prehistoric times to the present day, this possibility has sparked the imagination of philosophers, writers, and scientists. But for most of history, it was not an idea that was taken seriously. Philosophically, it was an unnecessary complication, one that simply pushed the mystery of our origins to a new layer of reality that was unobservable in principle. And, since a theory needs to be falsifiable in order to be scientific, many scientists did not see the multiverse as “real” science.
Aesthetically, too, the multiverse was not attractive. Scientists believed nature to be simple and economical. One universe was plenty, so why bother with more?
As our scientific understanding developed, however, it became clear that the multiverse is an unavoidable prediction of our theories of nature, ones that we trust and cherish: quantum mechanics, inflation, and string theory. Today, in the face of the inertia and prejudice of the past, the multiverse is finally entering the realm of serious scientific research. (continued)
A lengthy article but well worth reading; click here to continue. http://thewatchers.adorraeli.com/2014/02/09/beyond-the-universe/
This is an edited version of an article that originally appeared on Nautilus. Written by Laura Mersini-Houghton – Professor of Physics at the University of North Carolina.