Universe Today

May 17, 2009December 24, 2015 by Nancy Atkinson

Hubble Servicing Mission 4 in Pictures, Part 1

A view of the Hubble Space Telescope after it was captured by Atlantis' robotic arm. Credit: NASA

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The long-awaited Servicing Mission 4 for the Hubble Space Telescope has provided drama, nail-biting excitement, fist-pumping triumphs and ‘what else could go wrong now’ moments. But the best way to to describe the mission is to let the amazing images from the EVAs do the talking. Below are high-resolution images from NASA, highlighting the first three spacewalks.

Atlantis lifts off on May 11, 2009 for the Hubble Servicing Mission. Credit: NASA

The mission began with the picture-perfect, no-delay, long-awaited launch on May 11, 2009.

EVA #1

Astronauts John Grunsfeld (bottom) and Andrew Feustel, perched alone on the end of the Space Shuttle Atlantis remote manipulator system, perform the first of five STS-125 spacewalks. Credit: NASA — Astronauts John Grunsfeld (bottom) and Andrew Feustel, perched alone on the end of the Space Shuttle Atlantis' remote manipulator system, perform the first of five STS-125 spacewalks. Credit: NASA

The first spacewalk of the mission, performed by astronauts John Grunsfeld and Drew Feustel lasted a little over 7 1/2 hours. They successfully installed the new Wide Field Camera 3 science instrument and a new Science Instrument Command and Data Handling Unit. Both WFC-3 and the SI C&DH passed their “aliveness” tests, which essentially means the devices powered on correctly. The WFC-3 also passed its functional test, meaning the capabilities of the instrument itself were tested. The SI C&DH unit has also received an initial OK on its functional test, pending final review of data sent down to the ground.

Astronauts John Grunsfeld and Drew Feustel and their reflections in HST. Credit: NASA

A stubborn bolt threatened to thwart one of the spacewalk’s main goals, replacing the venerable space telescope’s workhorse optical camera with a new and improved instrument. But after a fair amount of old fashioned elbow grease, the WFPC2 was able to be removed.

A close-up of John Grunsfeld, taken by Drew Feustel. Credit: NASA

This close-up of Grunsfeld was taken by Drew Feustel, whose reflection is visible in Grunsfeld’s visor. Feustel is attached to the end of the shuttle Remote Manipulator System, or robotic arm. Grunsfeld was the free-floating astronaut for the EVA.

Drew Feustel hauls the new WFPC3 on the robotic arm, to install the camera on Hubble. Credit: NASA

Here, Feustel, on the end of the shuttle’s robotic arm, carries the piano-sized WFPC3 to its new home inside Hubble.
EVA #2

Astronaut Michael Good works with the Hubble Space Telescope in the cargo bay of the Earth-orbiting Space Shuttle Atlantis along with Mike Massimino. Credit: NASA

The second EVA of the mission provided some challenges to astronauts Michael Good and Mike Massimino. However, they achieved all the objectives for this spacewalk, it just took them awhile — 7 hours and 56 minutes. They installed three Rate Sensor Units (RSUs), with a pair of gyros in each, and the first of two new battery module units.

While standing on the end of Atlantis remote manipulator system arm, astronaut Michael Good, STS-125 mission specialist, pays tribute to his commander and all his crewmates with a military-style salute. Credit: NASA — While standing on the end of Atlantis' remote manipulator system arm, astronaut Michael Good, STS-125 mission specialist, pays tribute to his commander and all his crewmates with a military-style salute. Credit: NASA

Good and Massimino were not able to get one of the three prime RSUs into its slot but were able to install a spare, giving Hubble the new gyros it needed. The gyros are used to change the orientation of the telescope and keep it fixed on a particular astronomical target during observations.

While standing on the end of Atlantis remote manipulator system arm, astronaut Michael Good, STS-125 mission specialist, works on the Hubble Space Telescope. Credtit: NASA — While standing on the end of Atlantis' remote manipulator system arm, astronaut Michael Good, STS-125 mission specialist, works on the Hubble Space Telescope. Credtit: NASA

The spacewalkers also removed one of the original battery modules from Bay 2 of the telescope and replaced it with a new unit. The batteries provide power to the telescope when Hubble passes into Earth’s shadow and its solar arrays are not exposed to the sun. Ground controllers at Goddard’s Space Telescope Operations Control Center confirmed that all six gyroscopes and the new battery passed preliminary tests.

EVA #3

John Grunsfeld hangs on to Hubble. Credit: NASA

The third EVA of the mission went like clockwork as Grunsfeld and Feustel teamed up again. They removed the Corrective Optics Space Telescope Axial Replacement and installed in its place the new Cosmic Origins Spectrograph. They also completed an unprecedented repair of the Advanced Camera for Surveys replacing an electronic card and installed a new electronics box and cable.

Drew Feustel during the third EVA. Credit: NASA

To do the repairs on ACS, Grunsfeld removed 32 screws from an access panel to replace the camera’s four circuit boards and install a new power supply. The two astronauts used specially designed tools to do a job that was never intended to be done on orbit. But they did it, and with efficiency.

Grusnfeld and Feustel work together on EVA 3. Credit: NASA

Engineers at Goddard have already performed “aliveness” tests on both COS and ACS to verify they have electrical power. However while a functional test of the ACS indicated success in reviving the instrument’s heavily used wide-field channel, officials said early Sunday that it appears the repairs failed to resolve power problem with the camera’s stricken high-resolution channel and it appears “down for the count.”

We’ll keep you posted on any developments with ACS, and provide more high-resolution images from the remainder of the mission soon!

For more images from the mission, or to download higher resolution versions of the pictures here, visit NASA’s Human Spaceflight gallery.

May 17, 2009December 24, 2015 by Tammy Plotner

M94 – The “Cat’s Eye” Galaxy by Roth Ritter

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About 13 million light-years away in the constellations Canes Venatici, there’s a cloud. No, it’s not the same clouds that most of us have been experiencing lately – but a cluster of galaxies which appear form a single large cloud-like structure. The one we’re focusing on is Canes Venatici I, just a small section of the Virgo Supercluster and just moving along with the expansion of the Universe. In it we see a galaxy that stands out from the crowd for a very good reason… it has very little or no dark matter. It’s name? Messier 94.

When the very gifted Pierre Mechain discovered this galaxy on March 22, 1781, it took two days before Charles Messier had the chance to confirm his observation and catalog it as object 94. From Messier’s notes: “`Nebula without star, above the Heart of Charles [alpha Canum Venaticorum], on the parallel of the star no. 8, of sixth magnitude of the Hunting Dogs [Canes Venatici], according to Flamsteed: In the center it is brilliant and the nebulosity [is] a bit diffuse. It resembles the nebula which is below Lepus, No. 79; but this one is more beautiful and brighter: M. Mechain has discovered this one on March 22, 1781. (diam. 2.5′)”.

While most observers and some reference guides refer to M94 as a barred spiral galaxy (Sb), the notable feature of all is a dual ring structure – evidence of a low-ionization nuclear emission-line region (LINER) galactic nucleus. The inner core is a starburst ring, where many stars form rapidly and undergo supernovae at an astonishing rate. These starbursts may also be accompanied by the formation of galactic jets as matter falls into the central black hole forming a resonance pattern. Says C. Munoz-Tunon: “The bulge and the inner bar drive disk gas motion, causing inward movements outside the H II ring and outward just inside, thereby accumulating material to trigger star formation on the ring. In the central part the bar drives the gas toward the center, which explains the substantial amount of gas in the nucleus in spite of the presence of a fossil starburst. The peculiar motions reported in the literature in reference to the ionized gas of the H II ring can be understood as infalling gas encountering the shock waves generated by the starburst knots on the H II ring and being raised above the galaxy disk. The scenario of star formation propagating from the nucleus outward used to explain the apparent expanding motion of the HI ring is not fully supported, in light of a comparison of the location of the HI ring with that of the FUV ring. The FUV ring peaks at about 45″-48″, which might point to an inward-propagating star formation scenario.”

But, the point is arguable. According to the work of John Kormendy and Robert Kennicutt, it’s possible that what we’re seeing is simply an illusion of starburst caused by our viewing angle. “The Universe is in transition. At early times, galactic evolution was dominated by hierarchical clustering and merging, processes that are violent and rapid. In the far future, evolution will mostly be secular the slow rearrangement of energy and mass that results from interactions involving collective phenomena such as bars, oval disks, spiral structure, and triaxial dark halos. Both processes are important now. This review discusses internal secular evolution, concentrating on one important consequence, the buildup of dense central components in disk galaxies that look like classical, merger-built bulges but that were made slowly out of disk gas. We call these pseudobulges.”

Regardless of what caused the dual ring structure and declining rotation curves – the true answer is still elusive. Oddly enough it was what was proposed in 2008 which made Messier 94 even more mysterious… the lack of dark matter.

So, why should dark matter “matter”? That’s easy. We know its gravitational effects on visible matter and thereby we can explain the flat rotation curves of spiral galaxies, not to mention dark matter has a central role in galaxy structure formation and galaxy evolution. We owe these findings to Fritz Zwicky who told us that a a high mass-to-light ratio indicates the presence of dark matter in galaxies – just as he taught us that dark matter plays a role in galaxy clusters as well. Dr. Zwicky’s line of thinking was radical for the time… But is there still room for radical thinking? Why not?

According to the work of Joanna Jalocha, Lukasz Bratek and Marek Kutschera, ordinary luminous stars and gas account for all the material in M94 – with no room for dark matter. “The comparison of mass functions and rotation laws at the end of the previous section, illustrates the fact that the models with flattened mass distributions are more efficient than the commonly used models assuming spherical halo. The former are better in accounting both for high rotational velocities as well as for low scale structure of rotation curves and with noticeably less amount of matter than the latter (the relation between rotation and mass distribution in the disk model is very sensitive for gradients of a rotation curve). The use of the disk model is justified for galaxies with rotation curves violating the sphericity condition. This is necessary (although not sufficient) condition for a spherical mass distribution. Rotation of the spiral galaxy NGC 4736 can be fully understood in the framework of Newtonian physics. We have found a mass distribution in the galaxy that agrees perfectly with its high-resolution rotation curve, agrees with the I-band luminosity distribution giving low mass-to-light ratio of 1.2 in this band at total mass of 3.43 × 1010M, and is consistent with the amount of HI observed in the remote parts of the galaxy, leaving not much room (if any) for dark matter. Remarkably, we have achieved this consistency without invoking the hypothesis of a massive dark halo nor using modified gravities.

There exist a class of spiral galaxies, similar to NGC 4736, that are not dominated by spherical mass distribution at larger radii. Most importantly, in this region rotation curves should be reconstructed accurately in order not to overestimate the mass distribution. For a given rotation curve it can be easily determined whether or not a spherical halo may be allowed at large radii by examining the Keplerian mass function corresponding to the rotation curve (the so called sphericity test). By using complementary information of mass distribution, independent of rotation curve, we overcame the cutoff problem for the disk model, that for a given rotation curve, a mass distribution could not be found uniquely as it was dependent on the arbitrary extrapolation of the rotation curve.”

More explanation? Then step into MOND – Modified Newtonian dynamics where a modification of Newton’s Second Law of Dynamics (F = ma) is used to explain the galaxy rotation problem. It simply states that acceleration is not linearly proportional to force at low values. But will it work here? Who knows? Says Jacob Bekenstein: “The modified newtonian dynamics (MOND) paradigm of Milgrom can boast of a number of successful predictions regarding galactic dynamics; these are made without the assumption that dark matter plays a significant role. MOND requires gravitation to depart from Newtonian theory in the extragalactic regime where dynamical accelerations are small. So far relativistic gravitation theories proposed to underpin MOND have either clashed with the post-Newtonian tests of general relativity, or failed to provide significant gravitational lensing, or violated hallowed principles by exhibiting superluminal scalar waves or an {a priori} vector field.”

So next time you’re out observing galaxies, have a look at the “Cat’s Eye” Galaxy. Even a small telescope will reveal its bright, controversial nucleus and wispy shape. And thanks to outstanding astrophotographers like Roth Ritter we’re allowed to see a whole lot more…

Our thanks go to Roth Ritter of Northern Galactic for sharing his incredible work!

May 15, 2009December 24, 2015 by Nancy Atkinson

Marathon EVA for Hubble Astronauts

View from Mike Massimino's helmet camera of Mike Good using the Pistol Grip Tool. Credit: NASA TV

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The Hubble Space Telescope kept throwing curveballs at spacewalking astronauts on Friday, but with more elbow grease and a “if at first you don’t succeed, try again” attitude they were able to accomplish all the objectives for the second EVA of the repair mission. In what turned out to be the 8th longest spacewalk in US history, Mike Massimino and Mike Good replaced six gyroscopes – two wouldn’t fit, so spares had to be used — and four batteries. Both jobs were top priorities for the mission, and will give Hubble the power and control it needs to keep going until at least 2014, hopefully longer.

To start off the spacewalk, there were some tense moments when Massimino’s communication system didn’t work, and for about two minutes no one could hear him. “That was a little scary,” Good said after communication was reestablished.

Replacing the gyroscopes was the first task, and a big requirement for the mission. Three of the old gyroscopes no longer worked, and two others had been having problems recently.

Good helps Massimino out of the inside of Hubble. Credit: NASA TV

Massmino, who is over 6 feet tall, squeezed inside Hubble to begin removing the old gyros. “Trained my whole life for this,” he said.

The old gyroscopes came out with no problems, but two of the new ones didn’t “seat” correctly and couldn’t be bolted in. Two spares were retrieved and installed, but by the time the gyroscope task was completed, five hours had ticked by on the spacewalk. At one point later on in the EVA, the astronauts “plugged in” to get more oxygen to make sure they had enough for the rest of the lengthy excursion outside the shuttle.

The support crew inside the shuttle tried to keep things light to encourage the two spacewalkers. “My friend Leonidas has a couple of words for you guys that are appropriate right now,” shuttle commander Scott Altman told the spacewalkers, referring to the ancient Spartan king. “Remember this day, men, for it will be yours for all time.”

“We’ve got a little more work to do, but thanks,” Massimino replied.

Next on the agenda was replacing the huge batteries, which weigh over 500 lbs each. As the spacewalkers successfully finished that task, astronaut John Grunsfeld radioed, “Great job guys. Batteries ARE included on this flight!”

Good carries a replacement gyroscope to Hubble. Credit: NASA TV

Three more batteries will be replaced in an EVA next week.

The spacewalk ended after 7 hours and 56 minutes, surpassing another spacewalk back in 1993 to replace gyroscopes on Hubble.

“Every day has been ‘hold your breathe’ on this mission,” said Dave Leckrone, HST Senior Scientist at a press briefing following the EVA. “That points to the complexity of the observatory and what it takes to maintain it.”

On Saturday, the third spacewalk of the mission will replace the Cosmic Origins Spectrograph, and repair the Advanced Camera for Surveys. This will be the first time a repair — and mot just a replacement — of a Hubble instrument in space will be attempted.

May 15, 2009April 26, 2016 by Nancy Atkinson

New Star Trek Movie Beamed Up to Space Station

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In a convergence of science fiction and current technology, the new Star Trek movie has been “beamed up” to the International Space Station so the three occupants can watch it while orbiting 220 miles above Earth. Paramount sent a copy of the movie to NASA’s Mission Control, which then uplinked the movie to the International Space Station. The crew plans to watch the film on a laptop computer in the Unity module.

On board the station are NASA astronaut Michael Barratt, Russian cosmonaut and expedition commander Gennady Padalka, and astronaut Koichi Wakata from Japan.

“I remember watching the original Star Trek series and, like many of my NASA co-workers, was inspired by the idea of people from all nations coming together to explore space,” Barratt said in a statement provided by Paramount. “Star Trek blended adventure, discovery, intelligence and story telling that assumes a positive future for humanity. The International Space Station is a real step in that direction, with many nations sharing in an adventure the world can be proud of.”

Watching movies is one of the favored off-duty pastimes for ISS crews. There is a collection of DVDs and uplinked movies aboard the space station, some of which were delivered during previous shuttle and station missions and which will remain aboard for the enjoyment of future crews.

It’s not even the first time Star Trek has screened in space: Former station astronaut Greg Chamitoff and his crewmates viewed the entire Star Trek series as a regular weekly event.

Of course, if you want to see the new Star Trek movie, you don’t have to travel to the ISS; it’s now playing at movie theaters and IMAX screens. Check your local listings!

Source: SciFi Wire

May 15, 2009December 24, 2015 by Nancy Atkinson

On Your Mark, Get Set, Let’s Find Planets!

Artist concept of Kepler in space. Credit: NASA/JPL

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The checkout and calibration phase for the Kepler spacecraft has been completed, and now the telescope will begin one of the longest and most important stare-downs ever attempted. Kepler will spend the next three-and-a-half years staring at more than 100,000 stars searching for telltale signs of planets. Kepler should have the ability to find planets as small as Earth that orbit sun-like stars at distances where temperatures are right for possible lakes and oceans. “Now the fun begins,” said William Borucki, Kepler science principal investigator for the mission. “We are all really excited to start sorting through the data and discovering the planets.”

During the checkout phase scientists have collected data to characterize the imaging performance as well as the noise level in the measurement electronics. The scientists have constructed the list of targets for the start of the planet search, and this information has been loaded onto the spacecraft.

“If Kepler got into a staring contest, it would win,” said James Fanson, Kepler project manager at NASA’s Jet Propulsion Laboratory, Pasadena, Calif. “The spacecraft is ready to stare intently at the same stars for several years so that it can precisely measure the slightest changes in their brightness caused by planets.” Kepler will hunt for planets by looking for periodic dips in the brightness of stars — events that occur when orbiting planets cross in front of their stars and partially block the light.

The mission’s first finds are expected to be large, gas planets situated close to their stars. Such discoveries could be announced as early as next year.

We’ll be eagerly awaiting!

May 15, 2009December 24, 2015 by Tammy Plotner

Weekend SkyWatcher’s Forecast: May 15-17, 2009

Greetings, fellow SkyWatchers! With the Moon just a bit more out of the early evening picture, let’s enjoy the galaxy season as we begin our studies with one of the most massive and luminous spiral galaxies known. If it doesn’t hit you in the eye, then surely our globular cluster studies will! Be sure to set your clock early for Sunday morning to catch the pretty pairing of Jupiter and the Moon and end the weekend with one of the largest and brightest of the spiral galaxies in the Virgo Cluster. Are you ready? Then get your binoculars and telescopes out and I’ll see you in the back yard…

Friday, May 15, 2009 – Today we celebrate the 1857 birth on this date of Williamina Paton Stevens Fleming, who pioneered in the classification of stellar spectra and discovered the stars we now call white dwarfs. Now get this: she began by working as a maid for Harvard Observatory’s Edward Pickering, who then took her to the observatory to do clerical work. Fleming ended up cataloging over 10,000 stars for Harvard in a period 9 years. You go, girl!

Tonight let’s head out into space where we might get a “blackeye.” You’ll find it located just 1 degree east-northeast of 35 Comae Berenices, and it is most often called M64 (RA 12 56 43 Dec +21 41 00). Discovered by Bode about a year before Messier cataloged it, M64 is about 25 million light years away and holds the distinction of being one of the more massive and luminous spiral galaxies. It has a very unusual structure and is classified as an ‘‘Sa’’ spiral in some catalogs and as an ‘‘Sb’’ in others.

Overall, its arms are very smooth and show no real resolution to any scope, yet its bright nucleus has an incredible dark dust lane that consumes the northern and eastern regions around its core, giving rise to its nickname—the Blackeye Galaxy.

In binoculars, you can perceive this 8.5-magnitude galaxy as a small oval with a slightly brighter center. Small telescope users will pick out the nucleus more easily, but it will require both magnification and careful attention to dark adaptation to catch the dust lane. In larger telescopes, the structure is easily apparent, and you may catch the outer wisps of arms on nights of exceptional seeing. No matter what you use to view it, this is one compact and bright little galaxy!

Saturday, May 16, 2009 – Today we’d like to wish Roy Kerr a happy birthday! Born on this date in 1934, Kerr solved Einstein’s field equations of general relativity to describe rotating black holes, or the space/time around them. The solution, called now a Kerr black hole, shows a vortex-like region outside the event horizon known as the ergoregion. In this region, space and time are dragged around with the rotating parent black hole.

Tonight let’s use our binoculars and telescopes to hunt down one of the best globular clusters for the Northern Hemisphere— M3 (RA 13 42 11 Dec +28 22 31). You will discover this ancient beauty about halfway between the pair of Arcturus and Cor Caroli, just east of Beta Comae. The more aperture you use, the more stars you will resolve. Discovered by Charles Messier on May 3, 1764, this ball of approximately a half-million stars is one of the oldest formations in our galaxy. At around 40,000 light years away, the awesome M3 globular cluster spans about 220 light-years and is believed to be as much as 10 billion years old. To get a grasp on this concept, our own Sun is less than half that age! M3 is 40,000 years away, traveling at the speed of light; yet we can still see this great globular cluster.

Now let’s locate M53 (RA 13 12 55 Dec +18 10 09), near Alpha Comae. Aim your binoculars or telescopes there and you will find M53 about a degree northeast. This very rich, magnitude 8.7 globular cluster is almost identical to M3, but look at what a difference an additional 25,000 light-years can make to how we see it! Binoculars can pick up a small, round, fuzzy patch, while larger telescopes will enjoy the compact bright core as well as resolution at the cluster’s outer edges. As a bonus for scopes, look 1 degree to the southeast for the peculiar round cluster NGC 5053. Classed as a very loose globular, this magnitude 10.5 grouping is one of the least luminous objects of its type, due to its small stellar population and the wide separation between members, yet its distance is almost the same as that of M3.

Sunday, May 17, 2009 – If you’re up before dawn this morning, take a look at the close pairing of Jupiter and the Moon! Only about a finger-width apart, the magnificent duet will make starting the day a little more pleasant…

Now, as the Sun rises, salute the 1837 birth of Sir Joseph Norman Lockyer, who discovered and named the element helium that he found in the Sun’s atmosphere, even before it had been detected on Earth. Lockyer was the first to coin the term chromosphere for the Sun’s outer layer and was the co-discoverer of solar prominences!

Tonight we’ll return to 6 Coma Berenices, and head no more than a half degree southwest for another awesome galaxy— M99 (RA 12 18 49 Dec +14 25 00). Discovered by Pierre Mechain on the same night as he found M98, this is one of the largest and brightest of the spiral galaxies in the Virgo Cluster. Recognized second after M51 for its structure, Lord Rosse proclaimed it to be “a bright spiral with a star above.” It is an “Sc” class, and unlike its similarly structured neighbors, it rotates clockwise.

Receding from us at 2,324 kilometers per second, its speedy retreat through the galaxy fields and close pass to approachingM98may be the reason that it is asymmetrical, with a wide arm extending to the southwest. Three documented supernovae have been recorded in M99—in 1967, 1972, and 1986.

Possible in large binoculars with excellent conditions, this roughly 9th magnitude object is of low surface brightness and requires clean skies to see details. For a small telescope, you will see this one as fairly large, round, wispy, and with a bright nucleus. But, unleash aperture if you have it! For large scopes, the spiral pattern is very prominent, and the western arm shows well. Areas within the structure are patchworked with bright knots of stars and thin dust lanes, which surround the concentrated core region. During steady seeing, a bright, pinpoint stellar nucleus will come out of
hiding. A worthy study!

Until next week? Dreams really do come true when you keep on reaching for the stars!

This week’s awesome images are (in order of appearance): Williamina Paton Stevens Fleming (historical image), M64: the Blackeye Galaxy, M3 and M53 (credit—Palomar Observatory, courtesy of Caltech), Sir Norman Lockyer (historical image) and M99 (credit—Palomar Observatory, courtesy of Caltech). We thank you so much!

May 15, 2009December 24, 2015 by Nancy Atkinson

Amazing Images of Shuttle and Hubble Transiting Sun

In this tightly cropped image the NASA space shuttle Atlantis and the Hubble Space Telescope are seen in silhouette, side by side during solar transit at 12:17p.m. EDT, Wednesday, May 13, 2009, from west of Vero Beach, Florida. The two spaceships were at an altitude of 600 km and they zipped across the sun in only 0.8 seconds. Photo Credit: (NASA/Thierry Legault)

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No, these aren’t sunspots finally appearing on our currently quiet sun. Check out these amazing images taken by photographer Thierry Legault. The “spots” are actually the space shuttle Atlantis and the Hubble Space Telescope transiting across the sun! Legault’s website says these are the only images ever taken of a transit of a shuttle and the HST in front of the Sun. Legault was in Florida at the time he took this image, about 100 km south of the Kennedy Space Center on May 13th 2009 12:17 local time, several minutes before grapple of Hubble by Atlantis. The transit only lasted .8 seconds, and Legault was able to snap 4 images a second, getting a total of 16 different shots of the entire event (he started shooting 2 seconds before the predicted transit.)

He took another image the previous day of just the shuttle transiting (see below.)

In this tightly cropped image, the NASA space shuttle Atlantis is seen in silhouette during solar transit, Tuesday, May 12, 2009, from Florida. This image was made before Atlantis and the crew of STS-125 had grappled the Hubble Space Telescope. Photo Credit: (NASA/Thierry Legault)

Here, space shuttle Atlantis is seen in silhouette during solar transit, on Tuesday, May 12, 2009, also taken from Florida. This image was taken made before Atlantis and the crew of STS-125 had caught up with the Hubble Space Telescope.

Amazing!

See more on NASA’s Flickr page.

See more of Legault’s photographer here and here.

May 14, 2009December 24, 2015 by Fraser Cain

Triangulum Galaxy

There are three large spiral galaxies in our Local Group of galaxies. Our Milky Way is one, of course, and we’re joined by the Andromeda Galaxy. The third large spiral galaxy is the Triangulum Galaxy (Messier 33 or NGC 598).

The Triangulum Galaxy, also known as the Pinwheel Galaxy, is located about 3 million light-years away in the constellation Triangulum. In very bright skies you can see this galaxy with the unaided eye; although, there were no historical records of it before the invention of the telescope. It was probably first discovered by Giovanni Battista Hodierna in the 17th century, but it was first identified by Charles Messier in 1764.

Astronomers have estimated that Triangulum measures about 50,000 light-years across. That’s half the diameter of the Milky Way. It has an estimated mass between 10 and 40 billion solar masses.

While most galaxies are being carried away from the Milky Way by the expansion of the Universe, Triangulum is actually drifing towards us. Well, more specifically, it’s drifting towards the Andromeda Galaxy, and Andromeda is moving towards us. It’s approaching our galaxy at a speed of 24 km/second.

We have written many articles about galaxies for Universe Today. Here’s an article about the Triangulum galaxy.

If you’d like more info on galaxies, check out Hubblesite’s News Releases on Galaxies, and here’s NASA’s Science Page on Galaxies.

We have also recorded an episode of Astronomy Cast about galaxies – Episode 97: Galaxies.

May 14, 2009December 24, 2015 by Fraser Cain

Starburst Galaxy

All galaxies are going through some rate of star formation. New stars are being formed every year in the Milky Way. But some galaxies, classified as “starburst galaxies” are undergoing furious rates of star formation. Some are so active, they’re forming thousands of new stars every year.

So why do starburst galaxies form, when our own Milky Way has a relatively slow rate of new star formation? The most popular theory is that a galaxy is put into a starburst phase when it makes a close encounter with another galaxy. The gravitational interaction sends shockwaves through giant clouds of gas, causing them to collapse and form star forming regions. These create some of the most massive stars in the Universe; monster blue stars with more than 100 solar masses.

These massive stars live short lives and detonate as supernovae, blasting out more shockwaves into the galaxy. This creates a chain reaction that cascades through the galaxy. Within a few million years, the galaxy is forming stars at tens or even hundreds of times the rate of formation in a normal galaxy. And then when the gas is used up, within about 10 million years, the period of star formation ends.

Starburst galaxies are rare today, but astronomers have found that they were very common in the early Universe, when galaxies were closer and interacted more.

Thousands of starburst galaxies have been discovered across the Universe. One of the best known starburst galaxies is M82, located about 12 million light-years away in the constellation Ursa Major. The Hubble Space Telescope imaged the galaxy in 2005, and found 197 massive clusters of star formation going off simultaneously in the starburst core. The changes in M82 are being driven by its gravitationally interaction with nearby M81 galaxy.

We have written many articles about galaxies for Universe Today. Here’s an article about the starburst galaxy M82.

If you’d like more info on galaxies, check out Hubblesite’s News Releases on Galaxies, and here’s NASA’s Science Page on Galaxies.

We have also recorded an episode of Astronomy Cast about galaxies – Episode 97: Galaxies.

May 14, 2009December 24, 2015 by Nancy Atkinson

Is Everything Made of Mini Black Holes?

In 1971 physicist Stephen Hawking suggested that there might be “mini” black holes all around us that were created by the Big Bang. The violence of the rapid expansion following the beginning of the Universe could have squeezed concentrations of matter to form miniscule black holes, so small they can’t even be seen in a regular microscope. But what if these mini black holes were everywhere, and in fact, what if they make up the fabric of the universe? A new paper from two researchers in California proposes this idea.

Black holes are regions of space where gravity is so strong that not even light can escape, and are usually thought of as large areas of space, such as the supermassive black holes at the center of galaxies. No observational evidence of mini-black holes exists but, in principle, they could be present throughout the Universe.

Since black holes have gravity, they also have mass. But with mini black holes, the gravity would be weak. However, many physicists have assumed that even on the tiniest scale, the Planck scale, gravity regains its strength.

Experiments at the Large Hadron Collider are aimed at detecting mini black holes, but suffer from not knowing exactly how a reduced-Planck-mass black hole would behave, say Donald Coyne from UC Santa Cruz (now deceased) and D. C. Cheng from the Almaden Research Center near San Jose.

String theory also proposes that gravity plays a stronger role in higher dimensional space, but it is only in our four dimensional space that gravity appears weak.

Since these dimensions become important only on the Planck scale, it’s at that level that gravity re-asserts itself. And if that’s the case, then mini-black holes become a possibility, say the two researchers.

They looked at what properties black holes might have at such a small scale, and determined they could be quite varied.

Black holes lose energy and shrink in size as they do so, eventually vanishing, or evaporating. But this is a very slow process and only the smallest back holes will have had time to significantly evaporate over the enter 14 billion year history of the universe.

The quantization of space on this level means that mini-black holes could turn up at all kinds of energy levels. They predict the existence of huge numbers of black hole particles at different energy levels. And these black holes might be so common that perhaps “All particles may be varying forms of stabilized black holes.”

“At first glance the scenario … seems bizarre, but it is not,” Coyne and Cheng write. “This is exactly what would be expected if an evaporating black hole leaves a remnant consistent with quantum mechanics… This would put a whole new light on the process of evaporation of large black holes, which might then appear no different in principle from the correlated decays of elementary particles.”

They say their research need more experimentation. This may come from the LHC, which could begin to probe the energies at which these kinds of black holes will be produced.

Original paper.

Source: Technology Review