NASA has declared Comet ISON is no more
“Comet ISON, a “shining green candle in the solar wind,” is no longer with us, NASA declared Monday morning in a tribute to what many hoped would be the “comet of the century.”
On NASA’s Comet ISON Observing Campaign website, that ISON was “born 4.5 billion BC, fragmented Nov. 28, 2013 (age 4.5 billion yrs old).”“
Read more here: http://www.npr.org/blogs/thetwo-way/2013/12/03/248202813/comet-ison-is-no-more-nasa-says
M 81 (Bode’s Galaxy), M 82 (Cigar Galaxy) and part of IFN, Messier 81 (Bode’s Galaxy or NGC 3031) and Messier 82 (Cigar Galaxy or NGC 3034) are respectively spiral and starburst galaxy about 12 million light-years away in the constellation Ursa Major.This couple is seen through the faint glow of an Integrated Flux Nebulae (or IFN).
Credit: Emil Ivanov
A Guide to the Center of the Milky Way
The middle of our galaxy makes for a stunning desktop background – but what, exactly, is going on in this image?
This composite image is an oldie, but it’s a goodie. It was released back in 2009 in celebration of the International Year of Astronomy. At the time, it was the most detailed and most colorful image of the center of our galaxy ever assembled, a combination of near-infrared, infrared and X-ray images acquired by the Hubble Space Telescope, Spitzer Space Telescope and Chandra X-ray Observatory, respectively. You can explore in great detail in the high-res version featured here.
I bring it to your attention now because, for as many times as I’ve seen this image, I’ve never seen it annotated. There’s obviously a lot going on in this image, and beautiful though it may be, it would be helpful to know where one might find, say, the black hole that it presumably contains.
The above image, which I recently happened upon in a backdated NASA APOD post, serves as a helpful guide to the star fields, star clusters, gaseous filaments, supernova remnants and the energetic surroundings of the black hole thought to exist at the heart of the Milky Way (that would be the location labelled “Sagittarius A,” where a supermassive black hole four-million times as massive as the Sun resides).
The far side of the moon
The terrain is very different than the near side and recently UC Santa Cruz researchers published a study as to why that is. They theorize that there was a “giant splat" from an ancient smaller moon that caused this feature:
"The mountainous region on the far side of the moon, known as the lunar farside highlands, may be the solid remains of a collision with a smaller companion moon. The near side is relatively low and flat, while the topography of the far side is high and mountainous, with a much thicker crust. A Mars-sized object collided with Earth early in the history of the solar system and ejected debris that coalesced to form the moon. The study suggests that this giant impact also created another, smaller body, initially sharing an orbit with the moon, that eventually fell back onto the moon and coated one side with an extra layer of solid crust tens of kilometers thick."
Unpopular Astronomy Object Of The Week:
Quasars are a popular radio/optical/everything source in the sky, and not only are they one of the most brightest objects in the universe, but they are the product of super massive black holes.
But what many people do not know about is Quasar’s slightly different cousin, Blazar.
A Blazar are a very compact Quasar, that are pointing in the general direction of Earth. They are known to be highly energetic phenomenon, and because they usually point in the general direction of Earth, they will have a blueshift level.
Blazar are amazing objects, yet they are so unpopular that when they are typed(like in a word document), a red line is placed under it indicating “Blazar” is a spelling error. This is not the same case when “Quasar” is typed.
Blazars are commonly known to be in the gamma end of the spectrum, and it a studied topic in extragalactic astronomy. Even then, Blazars remain a rather unpopular object in contrast to Quasar, but this astronomy object should be more popular.
The violent encounter between two galaxies that may have been similar to the Milky Way has produced widespread star formation near a luminous core and along eye-catching tidal tails. Filled with dust, gas, and young blue star clusters, the opposing tidal tails extend well over 50,000 light-years from the merged nucleus. Likely triggered by the merger, accretion by a supermassive black hole drives activity within the nuclear region.
The star formation and its active galactic nucleus make NGC 2623 bright across the spectrum. This sharp cosmic snapshot of NGC 2623 (aka Arp 243) is based on Hubble Legacy Archive image data that also reveals even more distant background galaxies scattered through the field of view.
The sunlit edge of Titan’s south polar vortex stands out distinctly against the darkness of the moon’s unilluminated hazy atmosphere. The Cassini spacecraft images of the vortex led scientists to conclude that its clouds form at a much higher altitude — where sunlight can still reach — than the surrounding haze.
Titan (3,200 miles, or 5,150 kilometers across) is Saturn’s largest moon. This view looks toward the trailing hemisphere of Titan. North on Titan is up and rotated 32 degrees to the left. The image was taken with the Cassini spacecraft narrow-angle camera on July 14, 2013 using a spectral filter sensitive to wavelengths of near-infrared light centered at 938 nanometers. The view was obtained at a distance of approximately 808,000 miles (1.3 million kilometers) from Titan and at a Sun-Titan-spacecraft, or phase, angle of 82 degrees. Image scale is 5 miles (8 kilometers) per pixel.
New Evidence of an Asteroid Encountering a Pulsar
Pulsars - neutron stars formed during supernovae explosions - are often considered the “precision clocks” of radio astronomy. This is because of two fundamental properties observed from their radio pulses: the average emitted radio beam - known as the pulse profile - remains very stable over decades, and the pulsar has extreme rotational stability thanks to its fast rotation.
But the interesting thing about astronomy is even in a field where things are as precise as pulsars, surprises will still crop up. And this is what happened during a 24-year observing campaign of PSR J0738-4042, when in September 2005 the spin-down rate abruptly changed and a new radio component was observed. In fact, no previously understood mechanism can explain these changes, and the observations led the paper’s authors to propose they witnessed an asteroid encountering the pulsar.
Los Alamos National Laboratory RAPTOR telescopes in New Mexico and Hawaii received a very bright cosmic birth announcement for a black hole on April 27th.
The RAPTOR (RAPid Telescopes for Optical Response) system is a network of small robotic observatories that scan the skies for optical anomalies such as flashes emanating from a star in its death throes as it collapses and becomes a black hole - an object so dense that not even light can escape its gravity field.
This birth announcement arrived from the constellation Leo in the form of an exceptionally bright flash of visible light that accompanied a powerful burst of cosmic gamma-ray emissions.
What made such an extremely rare event even more spectacular for scientists, however, is that, in addition to the RAPTOR sighting, it was witnessed by an armada of instruments—including gamma-ray and X-ray detectors aboard NASA’s Fermi, NuSTAR and Swift satellites.
While the NASA instruments recorded some of the highest-energy gamma-ray bursts ever measured from such an event, RAPTOR noticed that the massive and violent transformation of a star into a black hole yielded a lingering “afterglow” that faded in lock-step with the highest energy gamma-rays.
"This was the burst of the century," said Los Alamos co-author James Wren. "It’s the biggest, brightest one to happen in at least 20 years, and maybe even longer than that."
"This afterglow is interesting to see," said paper co-author Przemek Wozniak of Los Alamos’s Intelligence and Space Research Division. "We normally see a flash associated with the beginning of an event, analogous to the bright flash that you would see coinciding with the explosion of a firecracker. This afterglow may be somewhat analogous to the embers that you might be able to see lingering after your firecracker has exploded. It is the link between the optical phenomenon and the gamma-rays that we haven’t seen before, and that’s what makes this display extremely exciting."
All things considered, the event was among the brightest and most energetic of its type ever witnessed.
This animation contains 96 images captured by the STEREO Behind spacecraft between November 28 at 00:08 and November 29 at 08:39 UTC.
Credit: NASA / STEREO / Emily Lakdawalla
NGC7822 by Didier CHAPLAIN & Laurent BOURGON
NGC 7822 is a young star forming complex in the constellation of Cepheus. The complex encompasses the emission region designated Sharpless 171, and the young cluster of stars named Berkeley 59. [**]
ISON update: It (probably) didn’t (completely) disintegrate
As ISON approached the Sun, astronomers – both professional and amateur – from all over the world got very excited. ISON started to flare up and get very bright, and then it vanished.
The comet started to dim and “smear” as it entered the occulter guarding NASA’s Solar and Heliospheric Observatory’s (SOHO) cameras, the Solar Dynamic Observatory caught some glimpses of “bright pixels,” but it wasn’t an astonishingly bright event. The early speculation was that ISON had completely disintegrated as it passed the Sun.
But, that’s not where the story ends…
As Phil Plait says, “It’s still possible that the initial reports of ISON’s death were somewhat exaggerated.” New images from SOHO show that ISON might still be fighting, just barely.
The “Comet of the Century” has had a lot of hype over the last year and a half, since it’s discovery in 2012. ISON is a new visitor to the inner solar system and it was set to pass within 1.2-million kilometers (730,000 miles) of the Sun. The potential to study both the origins of the Solar System and the structure of the Sun’s corona – all in the same event – was to good to pass up.
As I stated before, as the comet approached the Sun, something happened and ISON started to smear. It looked like the comet fizzed out before it even got started. Even if ISON disintegrated, scientists were suppose to see debris left over (which would be better for professional study, though not so good for amateur astronomy), but everything, the comet, the tail, everything, just vanished. Dean Pesnell, a project scientist with SDO summarized it most eloquently by saying “I’d like to know what happened to our half a mile of material that was going around the sun. Now’ it’s broken up and I didn’t see anything.”
Currently, material has reemerged from the other side of the Sun’s Corona. This is either a continuation of the tail that ISON left behind, or the comet itself. Current speculation is the dust that we see is simply dust, orbiting exactly as it should. The nucleus is probably lost.
So, what did we learn from this comet?
- We learned a lot about the original conditions of the solar system.
- Because the comet fizzed out so spectacularly, we learned that our models for comets and their composition has some serious problems; we need to figure out what those are so we can fix them.
As with all good celestial events, we are also left with a mystery… What happened to ISON while it was in SOHO’s occulter and invisible to SDO’s vision? As always, there is more than one possible answer to this mystery…
**UPDATE: 11/28 22:10 Eastern** It looks like part of ISON might have survived. We are seeing some brightening of ISON as it leaves the Sun. According to Phil Plait, comet astronomers are baffled and he is refusing to predict the comet’s actions any further. It keeps brightening, smearing, and vanishing without warning or a discernible pattern. We’ll keep you informed as the event continues to unfold.
Image credit: NASA/SOHO