Universe Today

March 5, 2011December 24, 2015 by Tammy Plotner

A New Spin On NGC 2403

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No. You’re not looking at a Hubble image. This incredibly detailed photo was taken with a 14.5″ telescope from right here on the surface of planet Earth. When Allan Sandage turned the Hale telescope its way, he discovered the first Cepheid variables beyond our local galaxy group. At the time he concluded its distance as about 8,000 light years away, but today it is believed to be as distant as 8,000,000. What’s its name? NGC 2403…

Discovered in 1788 by Sir William Herschel, this intermediate spiral galaxy is part of the M81/M82 group… and like its contemporaries, is a product of a galaxy merger. Its northern spiral arm connects to NGC 2404 – riddling the halo with young stars. In this masterful astrophoto done by Warren Keller, the pink and red regions denote active star formation, while clusters of neophyte suns gather in the blue OB associations. Like a fine piece of Irish lace, dark regions appear like holes where dust blocks the light. But NGC 2403 doesn’t follow the rules. Here the galaxy’s arms rotate at a different speed.

“High sensitivity H I observations of the nearby spiral galaxy NGC 2403 obtained with the VLA are presented and discussed. The properties of the extended, differentially rotating H I layer with its H I holes, spiral structure and outer warp are described. In addition, these new data reveal the presence of a faint, extended and kinematically anomalous component. This shows up in the H I line profiles as extended wings of emission towards the systemic velocity. In the central regions these wings are very broad (up to 150 km/s) and indicate large deviations from circular motion.” says F. Fraternali (et al). “We have separated the anomalous gas component from the cold disk and have obtained for it a separate velocity field and a separate rotation curve. The mass of the anomalous component is 1/10 of the total H I mass. The rotation velocity of the anomalous gas is 25-50 km/s lower than that of the disk. Its velocity field has non-orthogonal major and minor axes that we interpret as due to an overall inflow motion of 10-20 km/s towards the centre of the galaxy. The picture emerging from these observations is that of a cold H I disk surrounded by a thick and clumpy H I layer characterized by slower rotation and inflow motion towards the center. The origin of this anomalous gas layer is unclear. It is likely, however, that it is related to the high rate of star formation in the disk of NGC 2403 and that its kinematics is the result of a galactic fountain type of mechanism. We suggest that these anomalous H I complexes may be analogous to a part of the High Velocity Clouds of our Galaxy.”

Does this different rotational curve have an cosmological implications? According to the work of E. Battaner and E. Florido: “We review the topic of rotation curves of spiral galaxies emphasizing the standard interpretation as evidence for the existence of dark matter halos. Galaxies other than spirals and late-type dwarfs may also possess great amounts of dark matter, and therefore ellipticals, dwarf spirals, lenticulars and polar ring galaxies are also considered. Furthermore, other methods for determining galactic dark matter, such as those provided by binaries, satellites or globular clusters, have to be included. Cold dark matter hierarchical models constitute the standard way to explain rotation curves, and thus the problem becomes just one aspect of a more general theory explaining structure and galaxy formation. Alternative theories also are included. In the magnetic model, rotation curves could also be a particular aspect of the whole history of cosmic magnetism during different epochs of the Universe.”

Yet on the other hand, perhaps the differing rotations were caused by the merger itself – with no dark matter involved. “Quite a point has been made about deviations of some galaxies from flat rotation curves, specifically the decreased velocity in outer parts of the curves. Such cases can be explained under the diffusion model by considering collisions and tidal interactions between galaxies. In this explanation, the excess gravitational force is considered to be caused by a “cloud” of the agent that carries gravitational force that always is diffusing freely, although more concentrated in some regions than others as a result of the time required for the diffusion process and the size of the regions involved.” says Roy J. Britten. “When tidal interactions have occurred between galaxies, some momentum could be transferred between stars, gas, and dust that would not be shared by the diffusing clouds, and therefore, asymmetries in the gravitational forces would result. For example, the cloud and galaxies could separate if the two galaxies merged because the galaxies would share their momentum and the clouds would remain independent and continue to diffuse. Then, new gravitational clouds would be built slowly by diffusion from the merged galaxy.”

Dark matter or no dark matter, NGC 2403 (07h 36m 51.4s, +65° 36′ 09″) is a pleasure to observe. Located in the northern constellation of Camelopardalis, this 8.4 magnitude spiral galaxy can be spotted under dark sky conditions with ordinary 10X50 binoculars. In 1954 Fritz Zwicky reported a supernova event and 50 years later it happened again, keeping astronomers wondering about this galaxy with the low-luminosity “dwarf” Seyfert nucleus. SN2004 is the bright yellow “star” in this portrait and it is the closest – and brightest – stellar explosion discovered in more than a decade…

As close as your eyepiece on the next dark night!

Many thanks to Warren Keller of Billions and Billions and David Plesko for sharing their incredible work!

March 5, 2011December 24, 2015 by Jason Rhian

X-37B thunders off the pad on its way to orbit

The United Launch Alliance Atlas V carries the second OTV to orbit. Photo Credit: NASAtech.net

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CAPE CANAVERAL – Much has been made about the secretive nature of the Orbital Test Vehicle (OTV). Better known as the X-37B, the second of the U.S. Air Force’s OTVs roared off Cape Canaveral Air Force Station’s Launch Complex 41 at 5: 46 p.m. EDT. The Atlas V 501 thundered off of the launch pad carrying the second of the two OTVs into orbit.

The launch was to take place on Mar. 4, but looming cumulus clouds, high winds and rain pushed the launch back a day. The first launch window today opened at 4:09 p.m. EDT, however technical issues required minor work out on the launch pad and it was decided to try for launch during the second launch window’s opening.

Atlas Launch — This is the second launch of the mini unmanned X-37B space planes. Photo Credit: Jason Rhian

The first OTV, USA-212 lifted off from the exact same launch pad on 22 April 2010 and returned to Earth on Dec. 3, 2010. The return to earth tested out the space planes heat shield as well as the vehicle’s hypersonic aerodynamic aspects. The space plane is small enough to be carried within the U.S. space shuttle’s payload bay, it landed at Vandenberg Air Force Base in California. The craft suffered a tire blowout upon landing, but landed safely.

“The X-37B is a scientific achievement as well as a tremendous step in space operations. By itself, the ability to put a vehicle in space, conduct experiments and tests for close to nine months and then have that vehicle autonomously de-orbit and land is an important accomplishment,” said Major Tracy Bunko an Air Force spokeswoman. “This gives the Air Force the ability to examine how state-of-the-art, highly complex technologies will perform in space before they are made operational is an important cost-saving, risk-reducing capability.”

U.S. Air Force officials stated that the X-37B program has the potential of making space experiments much more affordable. This would allow future experiment designers to focus their resources and funds on technology and innovation rather than on what they currently are forced to expend them on – basic services, redundancy and ground operations.

March 5, 2011December 24, 2015 by Steve Nerlich

Astronomy Without A Telescope – Unreasonable Effectiveness

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Gravitational waves are apparently devilishly difficult things to model with Einstein field equations, since they are highly dynamic and non-symmetric. Traditionally, the only way to get close to predicting the likely effects of gravity waves was to estimate the required Einstein equation parameters by assuming the objects causing the gravity waves did not generate strong gravity fields themselves – and nor did they move at velocities anywhere close to the speed of light.

Trouble is, the mostly likely candidate objects that might generate detectable gravity waves – close binary neutron stars and merging black holes – have exactly those properties. They are highly compact, very massive bodies that often move at relativistic (i.e. close to the speed of light) velocities.

Isn’t it weird then that the ‘guesstimate’ approach described above actually works brilliantly in predicting the behaviors of close massive binaries and merging black holes. Hence a recent paper titled: On the unreasonable effectiveness of post-Newtonian approximation in gravitational physics.

So, firstly no-one has yet detected gravity waves. But even in 1916, Einstein considered their existence likely and demonstrated mathematically that gravitational radiation should arise when you replace a spherical mass with a rotating dumbbell of the same mass which, due to its geometry, will generate dynamic ebb and flow effects on space-time as it rotates.

To test Einstein’s theory, it’s necessary to design very sensitive detecting equipment – and to date all such attempts have failed. Further hopes now largely rest on the Laser Interferometer Space Antenna (LISA), which is not expected to launch before 2025.

The proposed Laser Interferometer Space Antenna (LISA) system using laser interferometry to monitor the fluctuations in the relative distances between three spacecraft, arranged in an equilateral triangle with five million kilometer sides. Hopefully, this will be sensitive enough to detect gravity waves. Credit: NASA.

However, as well as sensitive detection equipment like LISA, you also need to calculate what sort of phenomena and what sort of data would represent definitive evidence of a gravity wave – which is where all the theory and math required to determine these expected values is vital.

Initially, theoreticians worked out a post-Newtonian (i.e. Einstein era) approximation (i.e. guesstimate) for a rotating binary system – although it was acknowledged that this approximation would only work effectively for a low mass, low velocity system – where any complicating relativistic and tidal effects, arising from the self-gravity and velocities of the binary objects themselves, could be ignored.

Then came the era of numerical relativity where the advent of supercomputers made it possible to actually model all the dynamics of close massive binaries moving at relativistic speeds, much as how supercomputers can model very dynamic weather systems on Earth.

Surprisingly, or if you like unreasonably, the calculated values from numerical relativity were almost identical to those calculated by the supposedly bodgy post-Newtonian approximation. The post-Newtonian approximation approach just isn’t supposed to work for these situations.

All the authors are left with is the possibility that gravitational redshift makes processes near very massive objects appear slower and gravitationally ‘weaker’ to an external observer than they really are. That could – kind of, sort of – explain the unreasonable effectiveness… but only kind of, sort of.

Further reading: Will, C. On the unreasonable effectiveness of the post-Newtonian approximation in gravitational physics.

March 5, 2011December 24, 2015 by Nancy Atkinson

Podcast: Archaeoastronomy

Dr. Pamela Gay, a pyramid and a camel. Photo courtesy of Dr. Gay

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The Sun, Moon, stars and planets are visible to the unaided eye, and so they have been visible to astronomers since before recorded history. Some of the earliest records we do have tell us what the ancient astronomers thought about the heavens, and how they used the changing night sky in their daily lives.

Click here to download the episode.

Or subscribe to: astronomycast.com/podcast.xml with your podcatching software.

Archaeoastronomy shownotes and transcript.

March 4, 2011April 26, 2016 by Nancy Atkinson

Ground-Based Observations Capture Spacewalking Astronaut in Action

Astronaut Stephen Bowen (inside yellow box) was captured in this image during the March 2, 2011 spacewalk for STS-133. Credit: Ralf Vandebergh

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More impressive ground based images of the STS-133 mission, this time, Amateur astronomer Ralf Vandebergh of the Netherlands took images during one of the spacewalks for the mission, and likely captured astronaut Steve Bowen at work on the end of the Canadarm 2! Click on the image above, or go to Ralf’s website for a better view and more information.

Another amateur astronomer from the UK, Martin Lewis also took similar images of the spacewalk.

Ralf uses a 10 inch Newtonian telescope with a videocam eyepiece, and manually tracks the ISS and other objects across the sky. He takes most of his images in color to obtain the maximum possible information of the objects.

He took a similar image about 2 years ago of astronaut Joe Acaba on an EVA outside the ISS in March of 2009, which was featured on Astronomy Picture of the Day. He has also taken images of of ISS and Dexter, the special purpose manipulator, or this one of space shuttle Discovery on the STS-131 mission.

March 4, 2011December 24, 2015 by Jason Rhian

X-37B launch delayed due to weather

Poor weather dealyed the launch of the Air Force's Orbital Test Vehicle. Photo Credit: Jason Rhian

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CAPE CANAVERAL – Weather delayed the launch of the second of the United States Air Force’s Orbital Test Vehicles (OTV). The X-37B, as it is more commonly known, sate encapsulated within its fairing on top of the Atlas V 501 launch vehicle at Cape Canaveral Air Force Station (CCAFS).

It appeared that the launch might occur at the first launch window, which opened at 3:50 p.m. EDT. However high-level ground winds forced a delay. The second launch window was for 5:27 p.m. EDT, but by this time the winds had increased, Cumulous Clouds had moved into the area – bringing heavy rains in with them, forcing a scrub for the day. The plans are now for a 24-hour recycle of the launch, however tomorrow does not look much better with similar weather threatening the launch.

Looming clouds, high winds and eventually rain stopped the launch of the second of the Air Force's OTVs. Photo Credit: Jason Rhian

March 4, 2011December 24, 2015 by Nancy Atkinson

Spitzer Captures a Pink Sunflower in Space

Classifying Galaxies — This image from NASA's Spitzer Space Telescope shows infrared light from the Sunflower galaxy, otherwise known as Messier 63. Spitzer's view highlights the galaxy's dusty spiral arms. Image credit: NASA/JPL-Caltech

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Looking out my own window this morning provides a gloomy overcast view, so this new image from the Spitzer Space Telescope provides a day-brightener: a pink sunflower! This is the Sunflower galaxy, also known as Messier 63, and with Spitzers’ infrared eyes, the arms of the galaxy show up vividly. Infrared light is sensitive to the dust lanes in spiral galaxies, which appear dark in visible-light images. Spitzer’s view reveals complex structures that trace the galaxy’s spiral arm pattern.

Source: JPL
This galaxy is about 37 million-light years away from Earth, and lies close to the well-known Whirlpool galaxy and the associated Messier 51 group of galaxies.

March 4, 2011April 26, 2016 by Nancy Atkinson

NASA Mission to Europa May Fall to Budget Cuts

Europa During Voyager 2 Closest Approach. Credit: NASA/JPL

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Next week, the US National Academy of Sciences will release their decadal review of priorities for planetary science in 2013-2022, and it will be interesting to see how highly prioritized a mission to Jupiter’s enticing moon Europa will be. But according to Space News, word from the NASA Advisory Council’s planetary science subcommittee is that because of probable flat or declining budgets for building and operating planetary probes over the next five years, there will likely be no funding to begin development of a flagship-class mission such as a long-anticipated detailed survey of Europa.

“The out-years budget means no major new starts of a flagship planetary [mission],” Ronald Greeley, a regent’s professor at Arizona State University in Tempe and chairman of the NASA Advisory Council’s planetary science subcommittee, said during a March 1 conference call with panel members. “That’s a major, major issue for our community.”

The only flagship-class planetary mission in the works is the $2.5 billion Mars Science Laboratory Curiosity. The Juno mission to Jupiter, scheduled to launch in August 2011, is a medium-class “New Frontiers” mission set to study Jupiter only and not any of its moons.

The 2012 budget request for NASA, unveiled February 14, 2011 by President Obama, would boost spending on planetary science activities from the current level of $1.36 billion to $1.54 billion next year. But funding would steadily decline over the following four years, to $1.25 billion in 2016.

Space News reports that “NASA’s projected top-line budget is flat over the next five years at $18.72 billion, which when inflation is factored in translates into a decline in spending power. But there are budgetary scenarios under which NASA’s budget would decline over the next five years, even as the agency tries to replace the space shuttle and contends with runaway cost growth on the $5 billion-plus James Webb Space Telescope, the designated successor to the Hubble Space Telescope.”

Many have long hoped for mission to Europa, but budgetary issues have been a problem, even the past; the JIMO (Jupiter Icy Moon Orbiter) mission was canceled in 2005 because of lack of funding.

ESA and NASA have been studying a collaborative mission called Europa Jupiter System Mission/Laplace that would send two spacecraft to survey Jupiter and its moons. It is one of three candidates for a large-scale science mission opportunity that would launch around 2022. ESA has budgeted about $1 billion for the opportunity but is awaiting decisions from NASA and the Japanese space agency, which is collaborating on another candidate mission, before making a final decision on which one to pursue.

“How we will implement [the decadal priorities] within our existing budget needs to be considered,” NASA Planetary Science Division Director Jim Green said during the March 1 conference call, adding there is “no additional money beyond the president’s submitted budget.”

Source: Space News

March 4, 2011December 24, 2015 by Anne Minard

‘Climate Change Satellite’ Fails to Reach Orbit, Crashes in Ocean

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NASA’s Glory mission launched from Vandenberg Air Force Base in California Friday at 5:09:45 a.m. EST failed to reach orbit. Telemetry indicated the fairing, the protective shell atop the Taurus XL rocket, did not separate as expected about three minutes after launch. The failure represents a $420 million loss for NASA, and the loss of two important investigations related to climate change: ongoing data collection to monitor the sun’s energy reaching Earth, and a study of how aerosols move through Earth’s atmosphere and may influence climate.

This is the second time a Taurus XL rocket has failed to separate. NASA’s $273 million Orbiting Carbon Observatory crashed into the ocean in February 2009 due to a similar mishap. After that failure, Orbital Sciences redesigned the system. It has worked three times since on the company’s Minotaur rocket.

Source: NASA press release. Also see a previous story about the mission.

March 4, 2011December 24, 2015 by Ken Kremer

US Military X-37B rolls out to Atlas Launch Pad poised for March 4 launch – Photo Album

The secret X-37B mini space shuttle from the Air Force is encapsulated in a bisected 5 meter payload fairing and bolted atop an Atlas 5 rocket at Pad 41 at Cape Canaveral Air Force Station, Florida. This up close view of the nose cone holding the X 37-B includes the umbilical line attachments. Credit: Ken Kremer

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The second X-37B Orbital Test Vehicle (OTV-2) built for the US Air Force was rolled out today (March 3) to the Atlas rocket launch pad at Space Launch Complex-41(SLC-41) at Cape Canaveral Air Force Station, Florida.

The experimental OTV-2 is poised to blast off on Friday, March 4 on an Atlas V rocket in a launch window that extends from 3:39 pm to 5:39 p.m. EST. The X-37B is encapsulated in a 5 meter fairing.

The secret cargo and experiments loaded aboard are shrouded behind a veil of military security.

UPDATE: Due to weather concerns, the launch has been postponed until Saturday, March 5. Weather is predicted to improve to 40% favorable for launch.

Air Force technicians are completing final preparations for the late afternoon blast off of the bronze colored rocket topped by the extra long payload fairing to accommodate the OTV-2.

The rocket is sitting atop the mobile launch platform and was pushed about 1800 feet from the 31 story Vertical Integration Facility (VIF) to launch pad 41 by twin diesel powered trackmobiles. See my photo album of today’s X-37B rollout and close up visit to the Atlas rocket at SLC-41.

“No major changes were required from the OTV-1 flight based on post-flight assessments, but we did make a few minor modifications based on lessons learned from the first flight,” Tracy Bunko, Maj, USAF of the Air Force Press Desk told me in an interview.

“We’re pleased with what we’ve seen so far. Technology assessments are ongoing in areas including re-entry guidance, navigation, and control, thermal protection systems, and flight actuation systems.”

“We want to potentially test the landing capabilities in stronger wind conditions,” Bunko explained.

Read the mission preview and launch report by Jason Rhian

X-37B at Space Launch Complex 41 slated for March 4, 2011 launch after rollout of Atlas V rocket
from Vertical Integration Facility (left) pad 41 (right) at Cape Canaveral Air Force Station, Florida. Credit: Ken Kremer

Atlas V rocket with X-37B bolted atop at pad 41 at Cape Canaveral Air Force Station, Florida poised for March 4 launch. Credit: Ken Kremer

The X-37B is poised for launch on March 4, 2011 after rollout to pad 41 at Cape Canaveral Air Force Station, Florida. Credit: Ken Kremer

X-37B is encapsulated in a Swiss made five meter fairing.
Credit: Ken Kremer

The X-37B Orbital Test Vehicle (OTV) and Atlas V rocket bathed in xenon lights after March 3 rollout at Space Launch Complex-41 (SLC-41) at Cape Canaveral Air Force Station, Florida.
Launch scheduled for March 4. Credit: Ken Kremer
Photo taken from roof of CBS News building at KSC press site

Sequence of Photos showing rollout of Atlas V rocket, from right to left