An illustration of one of the zany metaphors about the black hole firewall paradox. Credit: Maki Naro via Txchnologist.
What happens if you fall into a black hole? According to Einstein’s general theory of relativity, the fall would be uneventful, until at some point the force of gravity would rip you apart. But a new theory suggests a different fate — and if correct, could challenge our understanding of gravity and how the universe works. Join the folks from the Kavli Foundation today, September 25, at 19:00 UTC (3 pm EDT, Noon PDT) as they host a live discussion and Q & A session about the latest theories about matter entering a black hole, and how these ideas are prompting researchers to reconsider our understanding of gravity.
They’ll be discussing the “blackhole firewall paradox” that you may have been hearing about lately.
You can watch live below. To submit questions ahead of time or during the webcast, send an email to [email protected] or post on Twitter with hashtag #KavliLive.
The panelists for the discussion includes Raphael Bousso (U.C. Berkeley), Juan Maldacena (Princeton University), Joseph Polchinski (Kavli Institute for Theoretical Physics at U.C. Santa Barbara), and Leonard Susskind (Stanford University).
This image of the star formation region NGC 6334 is one of the first scientific images from the ArTeMiS instrument on APEX. The picture shows the glow detected at a wavelength of 0.35 millimetres coming from dense clouds of interstellar dust grains. The new observations from ArTeMiS show up in orange and have been superimposed on a view of the same region taken in near-infrared light by ESO’s VISTA telescope at Paranal. Credit: ArTeMiS team/Ph. André, M. Hennemann, V. Revéret et al./ESO/J. Emerson/VISTA Acknowledgment: Cambridge Astronomical Survey Unit
And the “Cat’s Paw” was waiting to strike! In this exceptionally detailed image of star-forming region NGC 6334 we can get a sense of just how important new instrumentation can be. In this case it’s a new camera called ArTeMiS and it has just been installed on a 12-meter diameter telescope located high in the Atacama Desert. The Atacama Pathfinder Experiment – or APEX for short – operates at millimeter and submillimeter wavelengths, providing us with observations ranging between radio wavelengths and infrared light. These images give astronomers powerful new data to help them further understand the construction of the Universe.
Exactly what is ArTeMiS? The camera provides wide field views at submillimeter wavelengths. When added to APEX’s arsenal, it will substantially increase the amount of details a particular object has to offer. It has a detector array similar to a CCD camera – a new technology which will enable it to create wide-field maps of target areas with a greater amount of speed and a larger amount of pixels.
Like almost all new telescope projects, both personal and professional, the APEX team met up with “first light” problems. Although the ArTeMiS Camera was ready to go, the weather simply wouldn’t cooperate. According to the news release, very heavy snow on the Chajnantor Plateau had almost buried the building in which the scope operations are housed! However, the team was determined. Using a makeshift road and dodging snow drifts, the team and the staff at the ALMA Operations Support Facility and APEX somehow managed to get the camera to its location safely. Undaunted, they installed the ArTeMiS camera, worked the cryostat into position and locked the instrumentation down in its final position.
However, digging their way out of the snow wasn’t all the team had to contend with. To get ArTeMis on-line, they then had to wait for very dry weather since submillimeter wavelengths of light are highly absorbed by atmospheric moisture. Do good things come to those who wait? You bet. When the “magic moment” arrived, the APEX team was ready and the initial test observations were a resounding success. ArTeMiS quickly became the focus tool for a variety of scientific projects and commissioned observations. One of these projects was to image star-forming region NGC 6334 – the Cat’s Paw Nebula – in the southern constellation of Scorpius. Thanks to the new technology, the ArTeMiS image shows a superior amount of detail over earlier photographic observations taken with APEX.
What’s next for ArTeMiS? Now that the camera has been tested, it will be returned to Saclay in France to have even more detectors installed. According to the researchers: ” The whole team is already very excited by the results from these initial observations, which are a wonderful reward for many years of hard work and could not have been achieved without the help and support of the APEX staff.”
Early on, Mars had giant active volcanoes, which would have released significant methane. Because of methane’s high greenhouse potential, even a thin atmosphere might have supported liquid water. Credit: NASA
Using a phone to search for signs of life? Yeah, we can get behind that. One group of researchers has a system that they’ve been testing out in analog environments with the aim of (eventually, one day, they hope) it being applied, say, to other planets — such as Mars.
Here’s how it works:
“Initially the human astrobiologist takes images of his/her surroundings using a mobile phone camera. These images are sent via Bluetooth to a laptop, which processes the images to detect novel colors and textures, and communicates back to the astrobiologist the degree of similarity to previous images stored in the database,” read a press release on the technology.
View of Mars’ surface near the north pole from the Phoenix lander. Credit: NASA/JPL-Calech/University of Arizona
The aim is to eventually have robots, if necessary, do the same thing on Mars or in other locations. Field tests have been done in Martian analog environments, with intriguing results.
“In our most recent tests at a former coal mine in West Virginia, the similarity-matching by the computer agreed with the judgement of our human geologists 91% of the time,” stated Patrick McGuire, who works in Freie Universität’s planetary sciences and remote sensing department in Germany.
“The novelty detection also worked well, although there were some issues in differentiating between features that are similar in color but different in texture, like yellow lichen and sulfur-stained coalbeds. However, for a first test of the technique, it looks very promising.”
You can check out more details in this paper on Arxiv, a site that publishes articles before they are peer-reviewed. The information has also been accepted for publication in the International Journal of Astrobiology.
Artist's concept of NASA's Spitzer Space Telescope surrounded by examples of exoplanets it has looked at. Credit: NASA/JPL-Caltech
After 10 years in space — looking at so many galaxies and stars and other astronomy features — the Spitzer Space Telescope is being deployed for new work: searching for alien worlds.
The telescope is designed to peer in infrared light (see these examples!), the wavelength in which heat is visible. When looking at infrared light from exoplanets, Spitzer can figure out more about their atmospheric conditions. Over time, it can even detect brightness differences as the planet orbits its sun, or measure the temperature by looking at how much the brightness declines when the planet goes behind its star. Neat stuff overall.
“When Spitzer launched back in 2003, the idea that we would use it to study exoplanets was so crazy that no one considered it,” stated Sean Carey of NASA’s Spitzer Science Center, which is at the California Institute of Technology. “But now the exoplanet science work has become a cornerstone of what we do with the telescope.”
Of course, the telescope wasn’t designed to do this. But to paraphrase the movie Apollo 13, NASA was interested in what the telescope could do while it’s in space — especially because the planet-seeking Kepler space telescope has been sidelined by a reaction wheel problem. Redesigning Spitzer, in a sense, took three steps.
An example of Spitzer’s past work: This image from NASA’s Spitzer Space Telescope shows infrared light from the Sunflower galaxy, otherwise known as Messier 63. Spitzer’s view highlights the galaxy’s dusty spiral arms. Image credit: NASA/JPL-Caltech
Fixing the wobble: Spitzer is steady, but not so steady that it could easily pick out the small bit of light that an exoplanet emits. Engineers determined that the telescope actually wobbled regularly and would wobble for an hour. Looking into the problem further, they discovered it’s because a heater turns on to keep the telescope battery’s temperature regulated.
“The heater caused a strut between the star trackers and telescope to flex a bit, making the position of the telescope wobble compared to the stars being tracked,” NASA stated. In October 2010, NASA decided to cut the heating back to 30 minutes because the battery only needs about 50 per cent of the heat previously thought. Half the wobble and more exoplanets was more the recipe they were looking for.
The Spitzer Space Telescope. Credit: NASA
Repurposing a camera: Spitzer has a pointing control reference sensor “peak-up” camera on board, which originally gathered up infrared light to funnel to a spectrometer. It also calibrated the telescope’s star-tracker pointing devices. The same principle was applied to infrared camera observations, putting stars in the center of camera pixels and allowing a better view.
Remapping a camera pixel: The scientists charted the variations in a single pixel of the camera that showed them which were the most stable areas for observations. For context, about 90% of Spitzer’s exoplanet observations are about a 1/4 of a pixel wide.
That’s pretty neat stuff considering that Spitzer’s original mission was just 2.5 years, when it had coolant on board to allow three temperature-sensitive science instruments to function. Since then, engineers have set up a passive cooling system that lets one set of infrared cameras keep working.
Galaxy M60-UCD1 is an ultra-compact dwarf galaxy, and is packed with an extraordinary number of stars. Credit: X-ray: NASA/CXC/MSU/J.Strader et al, Optical: NASA/STScI
Meet galaxy M60-UCD1. This is not your average, every day, ordinary galaxy. First of all, it’s what is known as an ‘ultra-compact dwarf galaxy,’ which – as the name implies — are unusually dense and small galaxies. Additionally, it is the most luminous known galaxy of its type and one of the most massive, weighing 200 million times more than our Sun. But M60-UCD1 is jam-packed with an extraordinary number of stars, making it the densest galaxy in the nearby Universe that we know of. Stars in M60-UCD1 are thought to be 25 times closer together than the stars in our galaxy.
Quick and easy access to neighboring star systems (if you lived there) might be your first thought. But remember, space is big, no matter where you are.
“Traveling from one star to another would be a lot easier in M60-UCD1 than it is in our galaxy,” said Jay Strader of Michigan State University in Lansing, first author of a paper describing these results. “But it would still take hundreds of years using present technology.”
Ultra-compact dwarf galaxies were discovered about a decade ago. They are typically about only 100 light years across compared to the 1,000 light years or more than other dwarf galaxies. Our Milky Way galaxy is 120,000 light-years across.
This graph shows where M60-UCD1 fits in as far as luminosity and size. Credit: Strader et al.
Strader said that what makes M60-UCD1 so remarkable is that about half of its mass is found within a radius of only about 80 light years. This would make the density of stars about 15,000 times greater than found in Earth’s neighborhood in the Milky Way.
“Our discovery of M60-UCD1 lends support to the idea that ultra-compact dwarfs could be stripped-down version of more massive galaxies,” Strader wrote in a post on the Chandra blog. “The first reason is its mass: we estimate that it contains about 400 million stars, far more than observed for even massive star clusters, and much closer to the galaxy regime. We also observe that M60-UCD1 has two “parts”: an inner, even denser core embedded in a more diffuse field of stars. This structure is not expected for a star cluster, but it’s a natural outcome of the tidal stripping process that could produce an ultra-compact dwarf.”
And so, this UCD is providing astronomers with clues to how these types of galaxies fit into the galactic evolutionary chain.
Additionally, this galaxy appears to have a central black hole, as Chandra X-ray Observatory reveal the presence of an X-ray source sitting right at the center.
While supermassive black holes are known to be common in the most massive galaxies, it is unknown whether they occur in less massive galaxies like M60-UCD1, Strader said.
“Further observations of M60-UCD1 and other ultra-compact dwarfs could confirm a new, significant population of massive black holes,” Strader said. “These masses of these black holes would be notable: while most central black holes in galaxies have only a fraction of a percent of the mass of their host galaxies, in ultra-compact dwarfs the black holes could be a full 10% of the mass of the dwarf. This is because so many of the dwarf’s outer stars have been stripped away, essentially boosting the contribution of the unaffected central black hole to the total mass of the galaxy.”
M60-UCD1 is located near a massive elliptical galaxy NGC 4649, also called M60, about 60 million light years from Earth. The galaxy was discovered with NASA’s Hubble Space Telescope and follow-up observations were done with NASA’s Chandra X-ray Observatory, the Keck Observatory in Hawaii, and the Multiple Mirror Telescope in Arizona.
This view of Saturn's moon Enceladus and its prominent plumes was taken by the Cassini spacecraft on April 2, 2013. Credit: NASA/JPL-Caltech/Space Science Institute.
We can never get enough of seeing those intriguing jets and plumes from Saturn’s moon Enceladus, especially this great view from the Cassini spacecraft where the plumes are back-it from the Sun while the moon’s surface is lit with reflected light from Saturn. And as you can see, those jets are still firing. There are close to 100 geyser jets of varying sizes near Enceladus’s south pole spraying water vapor, icy particles, and organic compounds out into space. If you look closely, you’ll see the entire plume is as large as the moon itself.
Can we please send another spacecraft just to study this fascinating moon?
The image was taken in blue light with the Cassini spacecraft narrow-angle camera on April 2, 2013, when Cassini was about 517,000 miles (832,000 kilometers) from Enceladus.
A Soyuz rocket is rolled out to the launch pad by train on Monday, Sept. 23, 2013, at the Baikonur Cosmodrome in Kazakhstan. Credit: NASA/Carla Cioffi.
A new Soyuz is now on the pad, ready to bring the next crew to the International Space Station. Launch is scheduled for at 20:58 UTC (4:58 p.m. EDT) on September 25. This is the third Soyuz spacecraft to use the new abbreviated rendezvous trajectory with the ISS, where it will reach the space station in just a few hours instead of the usual two days.
Below is a video of the rollout to the pad.
You can see a great collection of images from the rollout, a press conference and more from NASA HQ’s Flickr page.
This Soyuz rocket will send Expedition 37 Soyuz Commander Oleg Kotov, NASA Flight Engineer Michael Hopkins and Russian Flight Engineer Sergei Ryazansky on a five-and-a-half month mission aboard the International Space Station.
In the past, Soyuz manned capsules and Progress supply ships were launched on trajectories that required about two days, or 34 orbits, to reach the ISS. For tomorrow’s launch, the Soyuz will rendezvous with the space station and dock after four orbits of Earth. The new fast-track trajectory has the rocket launching shortly after the ISS passes overhead. Then, additional firings of the vehicle’s thrusters early in its mission expedites the time required for a Russian vehicle to reach the Station.
Docking to the Poisk module on the Russian segment of the station is expected to occur at 02:47 UTC on Sept. 26 (10:47 p.m. EDT, Sept. 25) All the action of the launch and docking will be on NASA TV.
The new crew will join the current Expedition 37 crew of Commander Fyodor Yurchikhin, Karen Nyberg and Luca Parmitano of the European Space Agency.
Hopkins, Kotov and Ryazanskiy will remain aboard the station until mid-March. Yurchikhin, Nyberg and Parmitano, who have been aboard the orbiting laboratory since late May, will return to Earth Nov. 11, leaving Kotov as commander of Expedition 38.
The entire disk of the Earth lit during the equinox on September 22, 2013. Credit: Roscosmos / NTSOMZ / SRC "Planeta" / zelenyikot.livejournal.com
Here’s a fantastic view of our home planet taken by the Russian weather satellite Electro-L. And while Elektro-L can take gigantic photographs of the entire planet every 30 minutes, it only can get a fully-lit view like this just twice a year — at the spring and autumn equinoxes. This image was taken during the autumnal equinox on September 22, 2013.
Below is an animated gif of the view, going from day to night.
Animation of the Electro-L satellite’s view of Earth on September 22, 2013. Credit: Roscosmos / NTSOMZ / SRC “Planeta” / zelenyikot.livejournal.com
Elektro-L orbits Earth in a geostationary orbit 36,000 kilometers above the equator, and with the Sun exactly behind the satellite on the equinox — the day the north and south poles get the same amount of light — the entire disk is fully lit.
You can see the typhoon Usagi raging over Southeast Asia, clouds and rain over Russia and swirling clouds in the ocean near Antarctica.
Electro-L was launched in 2011 and is Russia’s first geostationary weather satellite. It’s a data hog – sending back 2.56 to 16.36 megabits per second, with resolution of 1 kilometer per pixel. You can see the big 5000 x 5000 pixel version at the Electro-L website.
Thanks to Vitaliy Egorov for sharing this image with UT. He has posted the images at his zelenyikot/livejournal website.
An oblique view of pyroclastic vents on Mercury via MESSENGER
Here on Earth we’re used to seeing volcanoes as towering mountains with steam-belching peaks or enormous fissures oozing lava. But on Mercury volcanic features often take the form of sunken pits surrounded by bright reflective material. They look like craters from orbit but are more irregularly-shaped, and here we have a view from MESSENGER of a cluster of them amidst a rugged landscape that stretches all the way to the planet’s limb.
The image above shows a group of pyroclastic vents on Mercury, located just north and east of the 180-mile (290-km) -wide, double-ringed Rachmaninoff crater. The vents lie in the center of a spread of high-reflectance material, sprayed out by ancient eruptions. This bright blanket of material stands out against Mercury’s surface so well, it has even been spotted in Earth-based observations!
An older vent can be seen at the bottom right, looking like a crater but with non-circular walls. North is to the left.
So why do Mercury’s volcanoes look so different than Earth’s? Planetary scientist David Blewett from Johns Hopkins University Applied Physics Laboratory explains:
“Volcanism on Mercury (and also the Moon) appears to have been dominated by flood lavas, in which large quantities if highly fluid (low-viscosity) magma erupts and flows widely to cover a large area. In this type of eruption, no large ‘volcano’ edifice is constructed,” David wrote in an email. “The lunar maria and many of Mercury’s smooth plains deposits were formed in this manner.”
“On both the Moon and Mercury there are also examples of explosive activity in which eruptions from a vent showered the surroundings with pyroclastic material (volcanic ash),” he added. “The vents and bright pyroclastic halos seen near Rachmaninoff on Mercury are examples, as well as numerous ‘dark mantle deposits’ on the Moon.”
The discovery and investigation of vents like these is extremely valuable to scientists, as they provide information on Mercury’s formation, composition, and the nature of volatiles in its interior. (Plus the oblique angle is very cool! Makes you feel like you’re flying along with MESSENGER over Mercury’s surface.)
See below for a wider view of the region and context of the placement of these vents to Rachmaninoff.
MESSENGER image of Rachmaninoff crater obtained in September 2009
We’re in the middle of Summer here on Vancouver Island, the Sun is out, the air is warm, and the river is great for swimming.
Three months from now, it’s going to be raining and miserable.
Six months from now, it’s still going to be raining, and maybe even snowing.
No matter where you live on Earth, you experience seasons, as we pass from Spring to Summer to Fall to Winter, and then back to Spring again.
Why do we have variations in temperature at all? What causes the seasons?
If you ask people this question, they’ll often answer that it’s because the Earth is closer to the Sun in the summer, and further in the winter.
But this isn’t why we have seasons. In fact, during Winter in the Northern Hemisphere, the Earth is actually at the closest point to the Sun in its orbit, and then farthest during the Summer. It’s the opposite situation for the Southern hemisphere, and explains why their seasons are more severe.
So if it’s not the distance from the Sun, why do we experience seasons?
We have seasons because the Earth’s axis is tilted.
Consider any globe you’ve ever used, and you’ll see that instead of being straight up and down, the Earth is at a tilt of 23.5-degrees.
The Earth’s North Pole is actually pointed towards Polaris, the North Star, and the south pole towards the constellation of Octans. At any point during its orbit, the Earth is always pointed the same direction.
For six months of the year, the Northern hemisphere is tilted towards the Sun, while the Southern hemisphere is tilted away. For the next six months, the situation is reversed.
Whichever hemisphere is tilted towards the Sun experiences more energy, and warms up, while the hemisphere tilted away receives less energy and cools down.
Consider the amount of solar radiation falling on part of the Earth.
When the Sun is directly overhead, each square meter of Earth receives about 1000 watts of energy.
But when the Sun is at a severe angle, like from the Arctic circle, that same 1000 watts of energy is spread out over a much larger area.
This tilt also explains why the days are longer in the Summer, and then shorter in the Winter.
The longest day of Summer, when the Northern Hemisphere is tilted towards the Sun is known as the Summer Solstice.
And then when it’s tilted away from the Sun, that’s the Winter Solstice.
When both hemispheres receive equal amounts of energy, it’s called the Equinox. We have a Spring Equinox, and then an Autumn Equinox, when our days and night are equal in length.
So how does distance from the Sun affect us?
The distance between the Earth and has an effect on the intensity of the seasons.
The Southern Hemisphere’s Summer happens when the Earth is closest to the Sun, and their winter when the Earth is furthest. This makes their seasons even more severe.
You might be interested to know that the orientation of the Earth axis is actually changing.
Over the course of a 26,000 year cycle, the Earth’s axis traces out a great circle in the sky. This is known as the precession of the equinoxes.
At the halfway point, 13,000 years, the seasons are reversed for the two hemispheres, and then they return to original starting point 13,000 years later.
You might not notice it, but the time of the Summer Solstice comes earlier by about 20 minutes every year; a full day every 70 years or so.
I hope this helps you understand why the Earth – and any planet with a tilted axis – experiences seasons.
