Shuttle Endeavour Rolled to Pad; Countdown to the Final Five Begins

Rollout of Endeavour atop mobile launch platform. Credit: Ken Kremer

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Space Shuttle Endeavour was rolled out to its seaside launch pad today (Jan. 6) at the Kennedy Space Center, officially starting the clock for the ‘Final Five’ flights. These five will close out the Space Shuttle era forever by the end of 2010 or early 2011 unless the program is extended for a few missions by President Obama.

I was totally thrilled to witness the trek first hand from just yards away as central Florida was gripped by a rare and truly ‘bone chilling’ cold snap. Endeavour was bolted atop the mobile launch platform (MLP) and hauled out to the pad at about 0.5 MPH by the giant crawler-transporter which dates back to the Apollo moon landing Era of the 1960’s.

The frigid 3.4 mile journey from the cavernous Vehicle Assembly Building (VAB) along the crawlerway to launch pad 39 A began in darkness in the overnight hours, with ‘first motion’ at 4:13 AM. The massive 17 million pound stack was declared ‘hard down” and secured at the pad at 10:37 AM.

Endeavour at Dawn. Credit: Ken Kremer

Along the way we observed a remarkable clump of icicles (see photo) that formed in the below freezing temperatures. So it felt more like sunny Antarctica then sunny Florida. And all us media and NASA technicians were outfitted with several layers of winter attire more appropriate for the recent ‘bone chilling’ Soyuz launch in Kazakhstan on Dec 20.

Endeavour is scheduled to liftoff on February 7, for what is currently planned to be the final night launch and is targeted for 4:39 AM. The goal of the 13 day STS 130 space station assembly mission is to deliver the last of three interconnecting nodes, dubbed ‘Tranquility’, along with the seven windowed Cupola observation module. See my earlier story here. NASA spokesman Allard Beutel said that these payloads will be delivered to the pad on Jan 15 and then be installed inside Endeavour’s giant cargo bay for the trip to space.

‘Tranquility’ is the final major US element remaining for the International Space Station (ISS) and will be attached to the Unity connecting Node. The unique Cupola module will afford astronauts a spectacular 360 degree panoramic view of the Earth, the station and the cosmos.

“Things are going really well for our launch on February 7th, according to Dana Hutcherson, the Endeavour flow director. We spoke as Endeavour was climbing up the last few meters of the ramp behind us leading to the pad. “We’re not tracking any major issues and there are no concerns at this time. We have about 7 days of contingency time in the pad flow. So everything is looking really well”.

Endeavour’s crew of six plans to arrive at the Cape on Jan 19 for several days of final training, equipment familiarization and a launch dress rehearsal, known as the Terminal Countdown Demonstration Test, or TCDT, which will simulate countdown activities at Kennedy. NASA’s executive level shuttle management team will meet on Jan 27 to review all aspects of mission processing and preparations and will then set an official launch date.

Photo Album of Endeavour Rollout on 6 Jan 2010 by Ken Kremer

Rollout of Endeavour  atop mobile launch platform, side view. Credit: Ken Kremer
Caption: Rollout of Endeavour atop mobile launch platform, side view. Credit: Ken Kremer

Reflections along the crawlerway. Credit: Ken Kremer
Endeavour climbs up ramp to Pad 39 A. Credit: Ken Kremer
Icicles form on a ‘bone chilling’ Sunny Florida day. Credit: Ken Kremer
Ken Kremer at Pad 39 A

Messier 102


Object Name: Messier 102
Alternative Designations: M102, NGC 5866, The Spindle Galaxy
Object Type: Lenticular Galaxy
Constellation: Draco
Right Ascension: 15 : 06.5 (h:m)
Declination: +55 : 46 (deg:m)
Distance: 45000 (kly)
Visual Brightness: 9.9 (mag)
Apparent Dimension: 5.2×2.3 (arc min)


Locating Messier 102: Locating Messier 102 isn’t particularly easy and will require a good start chart and some work. It’s rough location is about 10 degrees east/northeast of Eta Ursa Major – or about 10 degrees south of Gamma Ursa Minor. It will require at least a 4″ telescope at a relatively dark sky to be seen brightly, and will begin to show both structure and its dark dustlane at apertures approaching 6-8″. For smaller scopes, it will appear as a thin streak of nebulosity. If you are at a very dark sky site, you can use Iota Draconis and shift about 3 deg southwest in the direction of Eta Ursae Majoris or use Theta Bootis where M102 is just to the south.

What You Are Looking At: Located some 45 million light-years and part of a galaxy grouping, M102 is a wonderful lenticular galaxy seen almost edge-on. And seeing is believing! From this beautiful Hubble image and the words of Bill Keel: “The dust lane is slightly warped compared to the disk of starlight. This warp indicates that NGC 5866 may have undergone a gravitational tidal disturbance in the distant past, by a close encounter with another galaxy. This is plausible because it is the largest member of a small cluster known as the NGC 5866 group of galaxies. The starlight disk in NGC 5866 extends well beyond the dust disk. This means that dust and gas still in the galaxy and potentially available to form stars does not stretch nearly as far out in the disk as it did when most of these stars in the disk were formed.”

“The Hubble image shows that NGC 5866 shares another property with the more gas-rich spiral galaxies. Numerous filaments that reach out perpendicular to the disk punctuate the edges of the dust lane. These are short-lived on an astronomical scale, since clouds of dust and gas will lose energy to collisions among themselves and collapse to a thin, flat disk. For spiral galaxies, the incidence of these fingers of dust correlates well with indicators of how many stars have been formed recently, as the input of energy from young massive stars moves gas and dust around to create these structures. The thinness of dust lanes in S0s has been discussed in ground-based galaxy atlases, but it took the resolution of Hubble to show that they can have their own smaller fingers and chimneys of dust.”

But what happens when the stars are done forming? Take a look in infrared… “S0 galaxies are often thought to be passively evolved from spirals after star formation is quenched. To explore what is actually occurring in such galaxies, we present a multi-wavelength case study of NGC 5866—a nearby edge-on S0 galaxy in a relatively isolated environment. This study shows strong evidence for dynamic activities in the interstellar medium, which are most likely driven by supernova explosions in the galactic disk and bulge.” says Jiang-Tao Li (et al).

“Understanding these activities can have strong implications for studying the evolution of such galaxies. We utilize Chandra, Hubble Space Telescope, and Spitzer data as well as ground-based observations to characterize the content, structure, and physical state of the medium and its interplay with the stellar component in NGC 5866. A cold gas disk is detected with an exponential scale height of ~102 pc. Numerous distinct off-disk dusty spurs are also clearly present: prominent ones can extend as far as ~3 × 102 pc from the galactic plane and are probably produced by individual SNe, whereas faint filaments can have ~kpc scale and are likely produced by SNe collectively in the disk/bulge.”

But what’s hot can also be very cool… and it the Spindle Galaxy’s case it the amount of interstellar medium. Says G.K. Kacprzak (New Mexico State University) and G.A. Welch (Saint Mary’s University): “The nearly edge-on S0 galaxy NGC 5866 is notable for its massive molecular interstellar medium, prominent central dust lane, and large IRAS 100 micron flux. The galaxy is relatively isolated, and neither the kinematics nor morphology of the gas suggests that a merger has taken place. Instead, NGC 5866 may be entering an era of star formation fueled with gas donated by its aging stellar population. Are we seeing a counter example of the popular view that galaxies evolve through mergers? We explore that possibility using multi-transition CO observations and SCUBA (Submillimetre Common-User Bolometer Array) imagery of NGC 5866. We analyze the dust and gas components of the interstellar medium using techniques such as the large velocity gradient (LVG) models and a three-dimensional Monte Carlo radiation transfer code. A comparison of SCUBA and appropriately convolved H alpha images reveals both to have similar structure and morphology. This complements the fact that the SCUBA fluxes were under predicted by the Monte Carlo code which does not take star formation into account. Both of those facts indicate that NGC 5866 is indeed under going star formation.”

History: NGC 5866 was probably first turned up by Pierre Mechain during March 1781 – or was observed by Charles Messier himself around that time. Despite Mechain’s disclaimer 2 years later, chances are good that NGC 5866 is object #102 rather than a reclassification of Messier 101. (Considering the personal problems Messier was having during that period, it’s small wonder that an error could have been made.) While Messier orginally added it to his published catalog without verifying its position, he did return later to verify this beautiful galaxy was almost exactly 5 degrees preceding (west) of the actual position previously published. In his 1781 personal notes, Messier writes: “Nebula between the stars Omicron [actually Theta] Bootis and Iota Draconis: it is very faint; near it is a star of the sixth magnitude. (Handwritten position added by Messier in his personal copy: 14h 40m, +56.).”

Even Pierre Mechain was vexed by the error and his letter to Bernoulli on May 6, 1783, he writes: “I will add only that No. 101 & 102 on the p. 267 of the Connoissance des tems [for] 1784 are nothing but the same nebula, which has been taken for two, by an error in the [sky] charts.” Later, Bode would find in his notes: “On page 267 of the “Connoissance des Temps for 1784″ M. Messier lists under No. 102 a nebula which I have discovered between Omicron [actually Theta] Bootis and Iota Draconis; this is a mistake. This nebula is the same as the preceding No. 101. Mr. Messier, caused by an error in the sky charts, has confused this one in the list of my nebulous stars communicated to him.” Although the positioning error occurred, the description was correct for NGC 5866.

It’s Messier designation will probably forever by the subject of debate, but even other notable astronomers called in errors on this one as well. Both Herschels observed it and even Admiral Smyth – who probably following an error by John Herschel in his 1833 catalog, confuses its number with H I.219 (which is NGC 3665, a galaxy in Ursa Major), and thus erroneously gives that object’s discovery date, March 1789: “A small but brightish nebula, on the belly of Draco, with four small stars spreading across the field, north of it. There may be a doubt as to whether this is the nebula discovered by Mechain in 1789, since Messier merely describes it as “very faint,” and situated between Omicron Bootis and Iota Draconis. But there must be some mistake here; the one being on the herdman’s leg, and the other in the coil of the Dragon far above the head of Bootes, having 22 deg of declination and 44′ [44 min] of time [in RA] between them, a space full of all descriptions of celestial objects. But as the Theta in the raised right hand of Bootes, if badly made, might be mistaken for an omicron, this is probably the object seen by Mechain, and JH’s 1910 [NGC 5879]; it being the brightest nebula of five in that vicinity [actually, the brightest is NGC 5866]. A line from Kappa in Draco’s tail, led to the south-east of Thuban, and prolonged as far again, strikes upon its site.”

Don’t you mistake the beautiful Spindle Galaxy for anything but a great observation!

Top M102 image credit, Palomar Observatory courtesy of Caltech, M102 Hubble Images, 2MASS M102 image, M102 data images by AANDA and M102 image courtesy of NOAO/AURA/NSF.

WISE “First Light” Image Released

WISE First Light image. Image credit: NASA/JPL-Caltech/UCLA

Caption: WISE First Light image. Image credit: NASA/JPL-Caltech/UCLA

“In many respects, the most important moment for a telescope is its first light,” said Bill Irace, project manager for the Wide-field Infrared Survey Explorer (WISE) spacecraft, speaking at the 215th American Astronomical Society meeting. “And we are happy to be able to share WISE’s first light image with you today.” The image covers a patch of sky about three times larger than the full moon. An interstellar dust cloud shows in the upper left, and the bright object in the right-center is V 482 Carina, an old puffy, cool giant star. The image was taken with what will be WISE’s standard 8.8 seconds of exposure time where it “stares” at a specific point in the sky. Ultimately, WISE will take millions of images to conduct an all sky survey in 10 months, before the frozen hydrogen that keeps the instrument cold evaporates away.

The exposure shows infrared light from three of WISE’s four wavelength bands: Blue, green and red correspond to 3.4, 4.6, and 12 microns, respectively. WISE will search for millions of hidden objects, including asteroids, “failed” stars, powerful galaxies and brown dwarf stars too cool to emit light, including a potential brown dwarf that might be closer to Earth than Proxima Centauri. WISE data will also serve as navigation charts for other missions.

Irace and David Leisawitz from Goddard Space Flight Center said in about a month, the science team will release the first images from the first survey to the public. “Longer term, the astronomical community around the world has been looking forward to this,” said Leisawitz, “as all of WISE’s data will be released for anyone to use starting in April 2011, with the final release in March 2012. The data products include an atlas of images and catalog of individual objects.”

Leisawitz said that magnificently and stunningly, WISE provides 400 times better angular resolution than the infrared instrument on the COBE spacecraft.

Irace divulged that this image was strictly an engineering image with no regard to the field of view. “We actually took about six images, but this one was the prettiest,” he said. “We did not point at a particular point in the sky, and in fact we didn’t know if we were going to be able to do it this fast, so this is basically a random image.”

The science team believes the spacecraft will still be operational for 3 additional months following the 10 month prime mission, and are writing a proposal to NASA for funding to continue.

For a larger version of the image, visit this NASA webpage.

Source: AAS press conference

Measuring the Coronal Temperature with Iron

This image of the solar corona contains a color overlay of the emission from highly ionized iron lines and white light taken of the 2008 eclipse. Red indicates iron line Fe XI 789.2 nm, blue represents iron line Fe XIII 1074.7 nm, and green shows iron line Fe XIV 530.3 nm. This is the first such map of the 2-D distribution of coronal electron temperature and ion charge state. Credit: Habbal, et al.

Astronomers presenting at this week’s AAS conference have reported on new research measuring the temperature of the solar corona. The work combines observations of the Sun’s outer reaches from observations during total solar eclipses in 2006, 2008, and 2009. It utilized mapping of various abundances of ionized iron to build a two dimensional temperature map.

Although many introductory science classes paint temperature as a fixed number, in reality, it’s the average of a range of temperatures which is a way of quantifying the kinetic energy of the particles in question. Individual particles may be hotter (higher kinetic energy) while others may be cooler (lower kinetic energy). As these atoms move around, they can collide and these collisions will knock off electrons causing the atoms to become ionized. The degree of ionization will be indicative of just how energetic the collision was.

Those ionized atoms can then be identified spectroscopically or by using a filter to search for the wavelength at which those atoms will emit light as new electrons settle down into the previously vacated orbitals. By measuring the relative amounts of ionization astronomers can then reconstruct the range of kinetic energies in the gas and thus, temperature range which can, in turn, be used to determine the average temperature.

This is the method an international team of astronomers used to study the sun’s corona. Since light atoms don’t work well for this method (they become fully ionized or just can’t show a large range of ionization like atoms with more electrons), the astronomers chose to study the Sun’s corona through various states of iron ionization. In doing so they mapped several ionization states, including capturing for the first time, the elusive Fe IX lines (iron with 8 electrons knocked off) at 789.2 nm.

One interesting finding was that the region of emission extended to three solar radii (or 1.5 times the diameter). After this distance, the collision rate drops off and can no longer cause the ionization of atoms (however, radiative processes caused by photons from the sun can still ionize the atoms, but this is no longer indicative of the temperature of the atoms). This was further than originally anticipated.

Another result of their work showed that there is a strong correspondence between the amounts of various ions coming from the sun and that same ratio in interplanetary space as measured by the SWICS on the Advanced Composition Explorer. This connection will better help astronomers understand the working of our Sun as well as how its emissions may impact the Earth.

The full results of this work are to be published in the January 10 issue of the Astrophysical Journal.

Space Station Pictures

Mir

Here are some space station pictures. We’ve already done photo galleries of the International Space Station, but let’s take a look at some different stations as well:

This is a picture of the Mir Space Station, launched by Russia. This photograph was taken by the crew of STS-89 on the space shuttle Endeavour.


Space Station

Here is a recent image of the International Space Station captured by the crew of STS-129. It shows how much of the construction has now been completed.


Skylab

This is a picture of Skylab, the United States’ first space station. It was in orbit from 1973 to 1979, and was visited by 3 crews of astronauts.


Stanford Torus

And maybe some day we’ll live in a futuristic space station like this. It’s called a Stanford Torus, and rotates to provide the people living inside an artificial gravity.


Bigelow station

This is an artist’s impression of a future space hotel developed by Bigelow Aerospace. The various modules are inflated and connected together. Test versions of the modules have already been sent into orbit.

We’ve written many articles about the International Space Station for Universe Today. Here’s an article about how you can track the International Space Station, and here’s an article about a how a radio operator was able to communicate with the station.

If you’d like more info on the station, check out NASA’s mission page for ISS. And here’s a link to NASA’s human spaceflight page for the station.

We’ve also recorded an episode of Astronomy Cast about the space shuttle. Listen here, Episode 127: The US Space Shuttle.

Spitzer Peers Into the Small Magellanic Cloud

Spitzer Image of the Small Magellanic Cloud

This week at the AAC Conference, astronomers released a new image of the Small Magellanic Cloud (SMC, a dwarf galaxy just outside our Milky Way) from Spitzer. The purpose of the image was to study “the life cycle of dust in this galaxy.” In this life cycle, clouds of gas and dust collapse to form new stars. As those stars die, they create new dust in their atmosphere which will enrich the galaxy and, when the stars give off that dust, will be made available future generations of stars. The rate at which this process occurs determines how fast the galaxy will evolve. This research has shown that the SMC is far less evolved than our on galaxy and only has 20% of the heavy elements that our own galaxy has. Such unevolved galaxies are reminiscent of the building blocks of larger galaxies.

As with most astronomical images, this new image is taken in different filters which correspond to different wavelengths of light. The red is 24 microns and traces mainly cool dust which is part of the reservoir from which new star formation can occur. Green represents the 8 micron wavelength and traces warmer dust in which new stars are forming. The blue is even warmer at 3.6 microns and shows older stars which have already cleared out their local region of gas and dust. By combining the amount of each of these, astronomers are able to determine the current rate at which evolution is taking place in order to understand how the evolution of the SMC is progressing.

The new research shows that the tail (lower right in this image) is tidal in nature as it’s being tugged on by gravitational interactions with the Milky Way. This tidal interaction has caused new star formation in the galaxy. Surprisingly, the team of researchers also indicated that their work may indicate that the Magellanic Clouds are not gravitational bound to the Milky Way and may just be passing.

More images can be found at the JPL website.

Faster-Than-Light Pulsar Phenomena

Artist's impression of an anomalous X-ray pulsar. Credit: ESA

Observational data from nine pulsars, including the Crab pulsar, suggest these rapidly spinning neutron stars emit the electromagnetic equivalent of a sonic boom, and a model created to understand this phenomenon shows that the source of the emissions could be traveling faster than the speed of light. Researchers say as the polarization currents in these emissions are whipped around with a mechanism likened to a synchrotron, the sources could be traveling up to six times light speed, or 1.8 million km per second. However, although the source of the radiation exceeds the speed of light, the emitted radiation travels at normal light speed once it leaves the source. “This is not science fiction, and no laws of physics were broken in this model,” said John Singleton of Los Alamos National Laboratory at a press briefing at the American Astronomical Society meeting in Washington, DC. “And Einstein’s theory of Special Relativity is not violated.”

This model, called the superluminal model of pulsars, was described by Singleton and colleague Andrea Schmidt as solving many unanswered issues about pulsars.”We can account for a number of probabilities with this model,” said Singleton, “and there is a huge amount of observational data available, so there will be ample opportunities to verify this.”

Pulsars emit amazingly regular, short bursts of radio waves. Within the emissions from the pulses, the circulating polarization currents move in a circular orbit, and its emitted radiation is analogous to that of electron synchrotron facilities used to produce radiation from the far-infrared to X-ray for experiments in biology and other subjects. In other words, the pulsar is a very broadband source of radiation.

However, Singleton said, the fact that the source moves faster than the speed of light results in a flux that oscillates as a function of frequency. “Despite the large speed of the polarization current itself, the small displacements of the charged particles that make it up means that their velocities remain slower than light,” he said.

These superluminal polarization currents are disturbances in the pulsar’s plasma atmosphere in which oppositely-charged particles are displaced by small amounts in opposite directions; they are induced by the neutron star’s rotating magnetic field. This creates the electromagnetic equivalent of a sonic boom from accelerating supersonic aircraft. Just as the “boom” can be very loud a long way from the aircraft, the analogous signals from the pulsar remain intense over very long distances.

Rapid condensation of water vapor due to a sonic shock produced at sub-sonic speed creates a vapor cone (known as a Prandtl–Glauert singularity), which can be seen with the naked eye.

Back in the 1980s, Nobel laureate Vitaly Ginzburg and colleagues showed that such faster than light polarization currents will act as sources of electromagnetic radiation. Since then, the theory has been developed by Houshang Ardavan of Cambridge University, UK, and several ground-based demonstrations of the principle have been carried out in the United Kingdom, Russia and the USA. So far, polarization currents traveling at up to six times the speed of light have been demonstrated to emit tightly-focused bursts of radiation by the ground-based experiments.

Although Singleton and Schmidt’s highly technical presentation was admittedly over the heads of many in attendance (and watching online), LANL researchers said the superluminal model fits data from the Crab pulsar and eight other pulsars, spanning electromagnetic frequencies from the radio to X-rays. In each case, the superluminal model accounted for the entire data set over 16 orders of magnitude of frequency with essentially only two adjustable parameters. In contrast to previous attempts, where several disparate models have been used to fit small frequency ranges of pulsar spectra, Schmidt said that a single emission process can account for the whole of the pulsar’s spectrum.

“We think we can explain all observational data using this method,” Singleton said.

When asked, Singleton said they have received some hostile reactions to their model from the pulsar community, but that many others have been “charitably disposed because it explains a lot of their data.”

Lead image caption: Artist’s impression of an anomalous X-ray pulsar. Credit: ESA

Papers: Singleton et al,, Ardavan, et al, Ardavan, et al
Sources: AAS press conference, LANL,

Messier 101


Object Name: Messier 101
Alternative Designations: M101, NGC 5457, Pinwheel Galaxy
Object Type: Type Sc Spiral Galaxy
Constellation: Ursa Major
Right Ascension: 14 : 03.2 (h:m)
Declination: +54 : 21 (deg:m))
Distance: 27000 (kly)
Visual Brightness: 7.9 (mag)
Apparent Dimension: 22.0 (arc min)


Locating Messier 101: M101 is easily located by finding the first star (Eta) in the handle of the “Big Dipper” asterism in Ursa Major. It lays almost exactly the same distance north as the distance between Eta and the second star in the handle -Zeta. Simply form a mental triangle with the northern apex as your target position. From a good dark sky site, M101 can be spotted with larger binoculars as a vague, misty round patch – but doesn’t become apparent as a bright nucleus galaxy without the aid of a mid-sized telescope and show spiral structure to large aperture. Be aware that the outer edges are very vague and glimpses of patchy outside structure are actually star forming regions on Messier 101’s periphery. While the galaxy can be spotted under less than perfect sky conditions, it does require a good, dark night for serious study.

What You Are Looking At: At roughly 27 million light years away and spanning over 170,000 light years, Messier 101 is one of the biggest disc galaxies known so far. Shining with the light of about 30 billion suns, the Pinwheel galaxy is known as one of the most prominent Grand Design spiral galaxies in the sky – even if it is just a little lopsided… lopsided enough that Halton Arp has included M101 as No. 26 in his Catalogue of Peculiar Galaxies as a “Spiral with One Heavy Arm”. Why? Maybe because its interacting. According to Teresa Grabinska and Mirosaw Zabierowski; “We discuss Arp’s hypothesis that the HII regions are more numerous and more conspicuous on the side of a galaxy facing its companion. Arp’s hypothesis seems not to be true if we add to Hodge’s sets of galaxies only the most probably tidally-interacting cases.”

However, things get really interesting when we look at M101 with X-ray eyes. According to the work of Massimo Persic and Yoel Rephaeli: “Young galactic X-ray point sources (XPs) closely trace the ongoing star formation in galaxies… (The) relation provides the most adequate X-ray estimator of instantaneous SFR by the phenomena characterizing massive stars from their birth (FIR emission from placental dust clouds) through their death as compact remnants (emitting X-rays by accreting from a close donor).

Of course, all this activity means an increase in supernovae, doesn’t it? Darn right. “A new multiepoch Ha imaging study of M101 (NGC 5457) has been carried out as part of a larger campaign to study the rate and stellar population of extragalactic novae. The survey yielded a total of 13 nova detections from 10 epochs of M101 observations spanning a 3 year period.” says E.A. Coelho (et al). “The spatial distribution of the combined nova sample from the present survey and from the earlier Shafter et al. survey shows that the specific frequency of novae closely follows the integrated background light of the galaxy.”

But there’s still plenty of mystery left to discover in Messier 101. “After a review of the discovery of external galaxies and the early classification of these enormous aggregates of stars into visually recognizable types, a new classification scheme is suggested based on a measurable physical quantity, the luminosity of the spheroidal component. It is argued that the new one-parameter scheme may correlate well both with existing descriptive labels and with underlying physical reality. Two particular problems in extragalactic research are isolated as currently most fundamental. A significant fraction of the energy emitted by active galaxies (approximately 1% of all galaxies) is emitted by very small central regions largely in parts of the spectrum (microwave, infrared, ultraviolet and x-ray wavelengths) that were previously inaccessible to observation.” says J.P. Ostricker.

“The physical processes by which regions with the volume of the luminous stellar parts of galaxies produce such enormous quantities of energy are currently the subject of much speculative debate. It appears that most of the mass of ordinary galaxies resides far from the central luminous region, with the volume containing most of this mass times the volume containing most of the light-emitting stars; the nature, amount, and extent of this mass are quite unknown. New instruments that will be operating in the next decade and that may be helpful in solving these two problems are briefly mentioned with particular emphasis on the advances expected in angular resolution at wavelengths for which picture-taking ability has historically been poor or nonexistent.”

History: The Pinwheel Galaxy was discovered by Pierre Mechain on March 27, 1781, and added as one of the last entries in Charles Messier’s catalog as M101. Messier writes: “Nebula without star, very obscure and pretty large, of 6 or 7 minutes [of arc] in diameter, between the left hand of Bootes and the tail of the great Bear [Ursa Major]. It is difficult to distinguish when one lits the [graticule] wires.”

It would be Sir William Herschel who would shatter it into structure in 1783 when he writes in his unpublished notes: ” In the northern part is a large [bright] star pretty distinctly seen, and in the southern I saw 5 or 6 small [faint] ones glitter through the greatest nebulosity which appears to consist of stars. Evening bad. This and the 51st [M51] are both so far removed from the appearance of stars that it is the next step to not being able to resolve them. My new 20 feet will probably render it easy. On 1789, April 14 (Sw. 921). vB. SN. [very bright, small nucleus] with extensive nebulosity, pretty well determined on the preceding [W] side, but very diffuse to the north following [NE]. Includes the two following nebulae [III.788 and 789, NGCs 5461, 5462], and seems to extend 20′, perhaps 30′ or more.” Little did he know at the time he was actually picking up star forming regions!

However, by 1837 Admiral Smyth was beginning to get a clue. Says he: “This object was discovered by Mechain in 1781, in whose instruments it was very obscure; and it only exhibited a mottled nebulosity to WH [William Herschel]. Under a very favourable view it is large and well spread, though somewhat faint except towards the center, where it brightens. There are several telescopic stars in the field, one of which is very close to the nebula. From the nature of this neighborhood, and a trifling uncertainty in the earlier data, this object may be 214 H I [this is actually NGC 5474]; but that astronomer does not appear to have been aware of the identity. It is one of those globular nebulae that seem to be caused by a vast agglomeration of stars, rather than by a mass of diffused luminous matter; and though the idea of too dense a crowd may intrude, yet the paleness tells of its inconceivable distance, and probable discreteness.”

May you enjoy your 27 million light year journey into M101 as much!

Top M101 image credit, Palomar Observatory courtesy of Caltech, M101 Hubble Image, Messier 101 in UV by Ultraviolet Imaging Telescope (UIT and NASA), NASA’s Spitzer Space Telescope, Composite M101 as Viewed by Spitzer, Hubble and Chandra, Hubble B&W image and M101 image courtesy of George Jacoby, Bruce Bohannan, Mark Hanna/NOAO/AURA/NSF.

Early Release Science from Hubble WFC3 at AAS Conference

The image above is a newly released image from the Hubble Space Telescope. The image shows a mosaic of a portion of the Great Observatories Origins Deep Survey (GOODS) South Field nearly 1/3 the size of the full moon taken in September and October of 2009. It combines data taken in 10 filters that span the infrared to near ultraviolet. It made use of the newly installed Wide Field Camera 3 (WCF3) and the Advanced Camera for Surveys (ACS). The survey used 100 Hubble orbits for images from the ACS and 104 for the WCF3 images. Galaxies in the image are as faint as 26.5th to 27th magnitude which is several thousand times fainter than can be viewed with the naked eye and shows 7,500 galaxies.

Some of the first science results from this image were discussed this morning at the AAS conference in Washington.

The nearest galaxy in this image is an estimated 1 billion light years distant. The furthest are nothing more than faint red specks that are 13 billion light years away meaning their light left them just a half billion years after the Big Bang. This dynamic range adds to the large volume of images of galaxies over the history of the universe that allows them to understand how galaxies have formed and evolved.

It reveals that galaxy life in the early universe was especially chaotic. There is an increased number of galaxy mergers. Furthermore, many galaxies are so active with star formation they were blowing themselves apart into unusual shapes (similar to M 82). Although this has been seen in other surveys, this new image confirms the irregularity of shape in all wavelengths. Many of the most distant galaxies appear to be ellipticals although some show traces of faint spiral arms.

The image also shows that galaxies continue to build in mass from this chaotic past but the rate of growth slows around eight to ten billion years ago.

One surprise was that a type of galaxies that were uncharacteristically red (indicative of old stars and a lack of star formation) was discovered to have more star formation that previously expected. Astronomers had called these galaxies “red and dead” but ultraviolet detectors found traces of ongoing star formation in the cores and in weak spiral arms in these galaxies leading them to suspect the galaxies aren’t as dead as previously thought.

The full spectrum coverage also allows for estimates of redshift (an indicator of distance) for galaxies too faint to have their redshift taken spectroscopically. By combining observations in numerous filters Hubble can now give redshift measurements with as little as a 4% error.

Although the results posted at the A A S meeting are very preliminary there are many teams working on this newest data release. In the 2-3 months since the images were taken, 4 papers have been submitted for publication.

See a zoomable version of the image here.