Archive for the ‘Astronomy’ Category

Big Bang Monday: Comet of the Month

Monday, August 18th, 2014

Comet 67P/Churyumov-Gerasimenko activity on 2 August 2014. The image was taken by Rosetta’s OSIRIS wide-angle camera from a distance of 550 km. The exposure time of the image was 330 seconds and the comet nucleus is saturated to bring out the detail of the comet activity. Note there is a ghost image to the right. The image resolution is 55 metres per pixel.

ESA’s Rosetta Mission is sending back some very interesting images, especially for those who were curious about what these big rocks look like. It’s the first spacecraft to rendezvous with a comet.

The one from 7 August 20014 gave us a pretty good close-up…

Comet 67P/Churyumov-Gerasimenko imaged by Rosetta’s OSIRIS narrow angle camera on 7 August from a distance of 104 km.

Not as exciting as we’d expect, yet it’s most fascinating.

So how big is this comet? Thanks to @quark1972, now we now. Here’s the comet next to Los Angeles.

Big Bang Monday: The White Hole

Monday, August 11th, 2014

Check out this abstract

While most of the singularities of General Relativity are expected to be safely hidden behind event horizons by the cosmic censorship conjecture, we happen to live in the causal future of the classical big bang singularity, whose resolution constitutes the active field of early universe cosmology. Could the big bang be also hidden behind a causal horizon, making us immune to the decadent impacts of a naked singularity? We describe a braneworld description of cosmology with both 4d induced and 5d bulk gravity (otherwise known as Dvali-Gabadadze-Porati, or DGP model), which exhibits this feature: The universe emerges as a spherical 3-brane out of the formation of a 5d Schwarzschild black hole. In particular, we show that a pressure singularity of the holographic fluid, discovered earlier, happens inside the white hole horizon, and thus need not be real or imply any pathology. Furthermore, we outline a novel mechanism through which any thermal atmosphere for the brane, with comoving temperature of 20% of the 5D Planck mass can induce scale-invariant primordial curvature perturbations on the brane, circumventing the need for a separate process (such as cosmic inflation) to explain current cosmological observations. Finally, we note that 5D space-time is asymptotically flat, and thus potentially allows an S-matrix or (after minor modifications) AdS/CFT description of the cosmological big bang.

Got your head wrapped around it yet? Probably not. Our friends at Science Daily explain it a little more…

What we perceive as the big bang, they argue, could be the three-dimensional “mirage” of a collapsing star in a universe profoundly different than our own.

“Cosmology’s greatest challenge is understanding the big bang itself,” write Perimeter Institute Associate Faculty member Niayesh Afshordi, Affiliate Faculty member and University of Waterloo professor Robert Mann, and PhD student Razieh Pourhasan.

Conventional understanding holds that the big bang began with a singularity — an unfathomably hot and dense phenomenon of spacetime where the standard laws of physics break down. Singularities are bizarre, and our understanding of them is limited.

“For all physicists know, dragons could have come flying out of the singularity,” Afshordi says in an interview with Nature.

The problem, as the authors see it, is that the big bang hypothesis has our relatively comprehensible, uniform, and predictable universe arising from the physics-destroying insanity of a singularity. It seems unlikely.

So perhaps something else happened. Perhaps our universe was never singular in the first place.

Their suggestion: our known universe could be the three-dimensional “wrapping” around a four-dimensional black hole’s event horizon. In this scenario, our universe burst into being when a star in a four-dimensional universe collapsed into a black hole.

In our three-dimensional universe, black holes have two-dimensional event horizons — that is, they are surrounded by a two-dimensional boundary that marks the “point of no return.” In the case of a four-dimensional universe, a black hole would have a three-dimensional event horizon.

In their proposed scenario, our universe was never inside the singularity; rather, it came into being outside an event horizon, protected from the singularity. It originated as — and remains — just one feature in the imploded wreck of a four-dimensional star.

The researchers emphasize that this idea, though it may sound “absurd,” is grounded firmly in the best modern mathematics describing space and time. Specifically, they’ve used the tools of holography to “turn the big bang into a cosmic mirage.” Along the way, their model appears to address long-standing cosmological puzzles and — crucially — produce testable predictions.

Of course, our intuition tends to recoil at the idea that everything and everyone we know emerged from the event horizon of a single four-dimensional black hole. We have no concept of what a four-dimensional universe might look like. We don’t know how a four-dimensional “parent” universe itself came to be.

But our fallible human intuitions, the researchers argue, evolved in a three-dimensional world that may only reveal shadows of reality.

They draw a parallel to Plato’s allegory of the cave, in which prisoners spend their lives seeing only the flickering shadows cast by a fire on a cavern wall.

“Their shackles have prevented them from perceiving the true world, a realm with one additional dimension,” they write. “Plato’s prisoners didn’t understand the powers behind the sun, just as we don’t understand the four-dimensional bulk universe. But at least they knew where to look for answers.”

Still interested? I bet you are! Read more here. Relax: there’s a video on the Perimeter Institute site.


Big Bang Monday: 10 Years Gone for Cassini

Monday, June 30th, 2014

Today marks ten years since the Cassini spacecraft arrived at Saturn. The image above is one of my personal favorites (similar images also available via BigBangPrints.com).

The team of scientists at Cassini have selected their own “top 10″ list of images. More importantly, their list of the top ten discoveries is far more impressive…

  1. The Huygens probe makes first landing on a moon in the outer solar system (Titan)
  2. Discovery of active, icy plumes on the Saturnian moon Enceladus
  3. Saturn’s rings revealed as active and dynamic — a laboratory for how planets form
  4. Titan revealed as Earth-like world with rain, rivers, lakes and seas
  5. Studies of the great northern storm of 2010-2011
  6. Radio-wave patterns shown not to be tied to Saturn’s interior rotation as previously thought
  7. Vertical structures in the rings imaged for the first time
  8. Study of prebiotic chemistry on Titan
  9. Mystery of the dual bright-dark surface of Iapetus solved
  10. First complete view of the north polar hexagon and discovery of giant hurricanes at both of Saturn’s poles

I love the preview of what we can expect in the coming years…


Big Bang Monday: Four-Eyed Astronomy Photos

Monday, June 23rd, 2014

Photographer Vincent Brady made a contraption with four cameras, each fitted with fish-eye lenses, which he set up to do 360-degree panoramas. He calls them “Planetary Panoramas” and the results are amazing!

While experimenting with different photography tricks and techniques back in 2012, I was shooting 360 degree panoramas in the daytime and long exposures of the stars streaking in the sky at night. It suddenly became clear that the potential to combine the two techniques could be a trip! Since the Earth is rotating at a steady 1,040 mph I created a custom rig of 4 cameras with fisheye lenses to capture the entire night-sky in motion. Thus the images show the stars rotating around the north star as well as the effect of the southern pole as well and a 360 degree panorama of the scene on Earth. Each camera is doing nonstop long exposures, typically about 1 minute consecutively for the life of the camera battery. Usually about 3 hours. I then made a script to stitch all the thousands of these panoramas into this time-lapse. I created my rig in January of 2013 while in my final semester at Lansing Community College before receiving an associates degree in photography. Given it was winter in Michigan, I didn’t get to chase the notorious clear moonless night sky as much as I had hoped as the region has lots of cloud cover that time of year. Though I was ready on the rare night to go experiment. After graduating in May I had built up quite the urge to hit the road. My rig has taken me to firefly parties in Missouri, dark eerie nights at Devils Tower, through Logan Pass at Glacier National Park, up the mountains of British Columbia, and around the amazing arches and sandstone monuments in the Great American Southwest.

These are the images I created on the cold, dark, sleepless nights under awe-spiring skies.

The music is composed and recorded by my very good friend, the acoustic fingerpicking guitar prodigy Brandon McCoy! Brandon who is also from the greater Lansing area in Mid-Michigan is quite the acoustic instrumentalist. The song chosen for this time-lapse is called ‘One Letter From Lady.’ I moved to Michigan when I was 15 and Brandon was the first friend I made. He was the cool kid playing Pink Floyd licks on a $2 guitar at the time. Soon, after he had spent his cold, dark, sleepless nights perfecting his craft, he started coming up with his very own instrumentals. Some of which are upbeat by mixing picking, slapping, and drumming on the guitar while other compositions of his are calm and soothing and can put you in a meditative trance if you just close your eyes. It has been a great experience watching each other grow as artist for over the past 10 years, and you better believe we will be collaborating on projects like this in the very near future.

Phil Plait does an extraordinary job of explaining what’s going on here…

First are the weird star trails you see in many of the scenes. I’ve explained this before, but briefly: When you face north, east is to your right and west to your left, so the stars rise and set in a counterclockwise manner. If you face south, the reverse is true (west on your right, east on your left, and the stars move clockwise). If you look due east, the stars rise straight up, going over you head. Face west, and they move straight down to the horizon.

Normally, since you can only look in one direction at a time, you don’t have to deal with all these different movements all at once. But in the video we’re seeing the whole sky at the same time, with all those weird motions combined. So near the sky’s north pole the stars make little circles one way, and near the south pole (which is below the horizon in Michigan, where these shots were taken) they move the opposite way.

But there’s more! Once the images are stitched together, they can be mapped into different shapes. Just like you can take a map of the Earth and turn that into a spherical globe, a flattened Mercator projection, or any number of other types of shapes, you can do that with the sky as well. Brady reshaped the pictures several ways in the video, including using a (more or less) flat horizon facing east (at the 0:15 mark), which makes the stars rise out of the middle of the frame, and the same thing but facing south (at the 1:55 mark) and west (at the 2:19 mark) — all of which make the sky look very odd indeed.

But he also used something called the “Little Planet” effect, which is really weird. This takes the flat horizon and wraps it around into a circle, making the left side of the image touch the right, like rolling a rectangle up into a cylinder (or, more accurately a cone). The technique is pretty simple, and the end result is that it’s like you’re looking down on a tiny little planet or asteroid with the sky wrapped around it. This also tends to distort taller objects, lengthening them, so the arches (at the 0:30 mark) and hoodoos (at the 1:27 mark) look like they’re reaching toward you.

I’ll note that this is the opposite of the “all-sky” effect (at the 1:14 mark) where it looks like you’re looking up into the entire sky.

What fun! And all of this just from looking in all directions at once, and applying a little math to the result. I have to admit, I found it very disorienting (in a fun way) trying to pick out constellations and familiar landmarks in the sky during the video.

This is really cool and I hope he registers a patent!


Solar CME and The Group of Death

Thursday, June 12th, 2014

Not only are we expecting a space weather event

After producing a pair of R3 (Strong) Radio Blackouts in quick succession yesterday morning (10/1142 and 10/1252 UTC), active Region 2087 produced yet another R3 event today at 11/0906 UTC. Impacts from this activity were short lived and affected HF communications for the daylit side of Earth at the time of the flare. Continuing chances for more events R3 or greater events exists. Unlike yesterday, a Coronal Mass Ejection (CME) is not believed to be associated with this latest impulsive event. A CME assoicated with the activity yesterday morning has been observed moving at a flank from Earth and a glancing blow to Earth from this event is expected on June 13. An outside chance of at most G1 (Minor) Geomagnetic storms remains in the forecast.

…but we’ve got the Spain-Netherlands match, too! Group B is definitely this World Cup’s “group of death.”


Summer Sun in Thule

Monday, May 19th, 2014

Ah, summer in Greenland. Temparatures in the mid-20′s F and the sun is out — all day. Time to go out and take a stroll.

Let’s verify what Cryosat-2 sees from space. No need to be alarmed. Just follow the little yellow rope back to where you came from.

Meanwhile, on the other side, Antarctica is losing ice at an alarming rate! Read this abstract from Geophysical Research Letters and see what all the fuss is about…

We use 3 years of Cryosat-2 radar altimeter data to develop the first comprehensive assessment of Antarctic ice sheet elevation change. This new dataset provides near-continuous (96%) coverage of the entire continent, extending to within 215 kilometres of the South Pole and leading to a fivefold increase in the sampling of coastal regions where the vast majority of all ice losses occur. Between 2010 and 2013, West Antarctica, East Antarctica, and the Antarctic Peninsula changed in mass by −134 ± 27, −3 ± 36, and −23 ± 18 Gt yr−1 respectively. In West Antarctica, signals of imbalance are present in areas that were poorly surveyed by past missions, contributing additional losses that bring altimeter observations closer to estimates based on other geodetic techniques. However, the average rate of ice thinning in West Antarctica has also continued to rise, and mass losses from this sector are now 31% greater than over the period 2005–2011.

The ESA’s been tracking this for some time and getting something done before summer vacations hit in Europe is an honored tradition.




Big Bang Monday: Saturnian Encounter

Monday, May 19th, 2014

What if Saturn was only a million kilometers away? The gravity would kill us all.

If you’re curious, click on the video by Yeti Dynamics.

Saturn’s rings were created using Voyager data and Cassini Data, and tables from the IAU, and NASA Interestingly enough, the Voyager data and Cassini data did NOT completely match each other. More interestingly, the differences between the two data sets were not consistent along the ring, specifically the small Gaps along the rings are inconsistent between Voyager and Cassini. There are 3 conclusions I can reach from this,
1. the data is simply not perfectly accurate,
2. I interpreted the data incorrectly,
3. the Rings have actually changed a bit between voyager and cassini.

To create the rings, I interpolated between the two data sets, so the rings are a mix between Voyager and Cassini data, there are multiple textures used, for scattering, translucency, transparency, and color, I think I probably have some of the highest resolution textures in use anywhere on the web(over 19k pixels across).

In Part 1, (the 2d blue print video) the Planets are all correctly scaled to each other, except the SUN.. The Orbits are also all correctly scaled to each other (except the Moon’s). However, the planet size, and the planet orbits are not scaled to each other. The orbital speeds are also all correct relative to one another,

In part 2, The illumination between the moon and Saturn is reasonably accurate, in case you didn’t understand. This is Saturn as Far away as the closest approach mars would get

In Part 3, the meteors ramp up and down in response to going through the very distended outer rings E, and G

The Meteors are Greenish, I’ve actually seen a Number of large daylight meteors, all of them had flashes of green and blue, The velocity and direction they are in the video is accurate to the motion of Saturn in this video

Disclaimer:
This will.. never never ever happen, ever (probably).

Hat tip: Bad Astronomer

Now’s a really good time to view Saturn.

Of course, the best way to get Saturn up on your wall, permanent-like, is to get a Big Bang Print.


Neutron Stars Collide

Wednesday, May 14th, 2014

Thank you, NASA!

This supercomputer simulation shows one of the most violent events in the universe: a pair of neutron stars colliding, merging and forming a black hole. A neutron star is the compressed core left behind when a star born with between eight and 30 times the sun’s mass explodes as a supernova. Neutron stars pack about 1.5 times the mass of the sun — equivalent to about half a million Earths — into a ball just 12 miles (20 km) across.

As the simulation begins, we view an unequally matched pair of neutron stars weighing 1.4 and 1.7 solar masses. They are separated by only about 11 miles, slightly less distance than their own diameters. Redder colors show regions of progressively lower density.

As the stars spiral toward each other, intense tides begin to deform them, possibly cracking their crusts. Neutron stars possess incredible density, but their surfaces are comparatively thin, with densities about a million times greater than gold. Their interiors crush matter to a much greater degree densities rise by 100 million times in their centers. To begin to imagine such mind-boggling densities, consider that a cubic centimeter of neutron star matter outweighs Mount Everest.

By 7 milliseconds, tidal forces overwhelm and shatter the lesser star. Its superdense contents erupt into the system and curl a spiral arm of incredibly hot material. At 13 milliseconds, the more massive star has accumulated too much mass to support it against gravity and collapses, and a new black hole is born. The black hole’s event horizon — its point of no return — is shown by the gray sphere. While most of the matter from both neutron stars will fall into the black hole, some of the less dense, faster moving matter manages to orbit around it, quickly forming a large and rapidly rotating torus. This torus extends for about 124 miles (200 km) and contains the equivalent of 1/5th the mass of our sun.

Scientists think neutron star mergers like this produce short gamma-ray bursts (GRBs). Short GRBs last less than two seconds yet unleash as much energy as all the stars in our galaxy produce over one year.

The rapidly fading afterglow of these explosions presents a challenge to astronomers. A key element in understanding GRBs is getting instruments on large ground-based telescopes to capture afterglows as soon as possible after the burst. The rapid notification and accurate positions provided by NASA’s Swift mission creates a vibrant synergy with ground-based observatories that has led to dramatically improved understanding of GRBs, especially for short bursts.

By 7 milliseconds, tidal forces overwhelm and shatter the lesser star. Its superdense contents erupt into the system and curl a spiral arm of incredibly hot material. At 13 milliseconds, the more massive star has accumulated too much mass to support it against gravity and collapses, and a new black hole is born. The black hole’s event horizon — its point of no return — is shown by the gray sphere. While most of the matter from both neutron stars will fall into the black hole, some of the less dense, faster moving matter manages to orbit around it, quickly forming a large and rapidly rotating torus. This torus extends for about 124 miles (200 km) and contains the equivalent of 1/5th the mass of our sun.


Big Bang Monday: Meteors Showers Predicted

Monday, May 12th, 2014

Get ready, watchers of the skies!

Periodic Comet 209P/LINEAR is predicted to put on a show for us.

Preliminary results by Esko Lyytinen and Peter Jenniskens, later confirmed by other researchers, predict 209P/LINEAR may cause the next big meteor shower which would come from the constellation Camelopardalis on the night of 23/24 May 2014. There may be 100 to 400 meteors per hour. All the trails from the comet from 1803 through 1924 may intersect Earths orbit during May 2014. The peak activity is expected to occur around 24 May 2014 7h UT when dust trails produced from past returns of the comet may pass 0.0002 AU (30,000 km; 19,000 mi) from Earth.

This April 30, 2014 image was taken using the NASA Marshal Space Flight Center 20″ telescope located in New Mexico. A 3-minute exposure, it shows 14th magnitude Comet 209P/LINEAR shining faintly among the stars of Ursa Major. At the time of this image, 209P was just over 40 million km from Earth, heading for a relatively close approach (8.3 million km) with us on May 29, 2014.

Image credit: NASA/MSFC/Bill Cooke


Big Bang Monday: Cassini’s Looking at Uranus

Monday, May 5th, 2014

While pondering the possibility of geosynchronous spacecraft running into an out-of-control or very inclined one (around the 150-deg. West area), I was reminded there’s a reason we call it “space.” There’s a lot of it out there.

The gorgeous image from our friends at the Cassini Solstice Mission is one that’ll make you think about space.

Here’s their description

Uranus is a pale blue in this natural color image because its visible atmosphere contains methane gas and few aerosols or clouds. Methane on Uranus – and its sapphire-colored sibling, Neptune – absorbs red wavelengths of incoming sunlight, but allows blue wavelengths to escape back into space, resulting in the predominantly bluish color seen here. Cassini imaging scientists combined red, green and blue spectral filter images to create a final image that represents what human eyes might see from the vantage point of the spacecraft.

Uranus has been brightened by a factor of 4.5 to make it more easily visible. The outer portion of Saturn’s A ring, seen at bottom right, has been brightened by a factor of two. The bright ring cutting across the image center is Saturn’s narrow F ring.

Uranus was approximately 28.6 astronomical units from Cassini and Saturn when this view was obtained. An astronomical unit is the average distance from Earth to the sun, equal to 93,000,000 miles (150,000,000 kilometers).

This view was acquired by the Cassini narrow-angle camera at a distance of approximately 614,300 miles (988,600 kilometers) from Saturn on April 11, 2014. Image scale at Uranus is approximately 16,000 miles (25,700 kilometers) per pixel. Image scale at Saturn’s rings is approximately 4 miles (6 kilometers) per pixel. In the image, the disk of Uranus is just barely resolved. The solar phase angle at Uranus, seen from Cassini, is 11.9 degrees.

The images our space program produce are free. Getting big print made suitable for framing is available here. They do custom orders, so if you don’t see what you want — go out and find it, then have it done that way you like it.