Book Review: An Ocean of Air

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Invisible, forceful, noisy and ever-present. We can’t get away from the air surrounding our bodies. It keeps us balanced, allows us to communicate, but most of all facilitates the ready transport of energy and material. Gabrielle Walker in her book An Ocean of Air – Why the Wind Blows and Other Mysteries of the Atmosphere reawakens our knowledge and appreciation of this wondrous medium. Her stories amplify the importance that humanity’s placed on air and the results of our continuing interest in this fascinating, ethereal element.

In ancient times, the air was credited with being a fundamental element. Though unseen and barely felt, people recognized it as being an essential commodity. Yet, with the dawn of enlightenment, certain individuals let their curiosity guide them into realms yet visited. Playing with enclosed spaces, altering temperatures, and capturing exhaust from chemical reactions all allowed these investigators to learn more and more about our featureless but very particular and special atmosphere. Now, with certainty, we know about the composition of air’s chemical elements, air’s different layers when ascending, and its role in moving dust and water about the Earth’s surface. But, its been hundreds of years of journeying in fits and starts that resulted in what we know about the air enveloping and protecting Earth’s surface.

Gabrielle Walker’s book gently accompanies the reader along the journey of humankind’s learning about Earth’s atmosphere. Within, she begins with Galileo and his measuring of the weight of air and ends with the confirmation of the existence of the Van Allen protective belts. However her approach for relaying humanity’s progress is far removed from the typical recitation of facts that are found in text books. Rather, she progresses from one unique personality to another during her chronology. For instance, after Galileo, she portrays Evangelista Torricelli, a compatriot of Galileo but who disagreed with some of Galileo’s ideas. She writes how Torricelli experimented but was afraid to promulgate results because of the Church and its belief in the heretical nature of a vacuum. Later, there’s Oliver Heaviside, a striking, very, very strange man who wore a tea cozy on his head and manicured his nails cherry red. Nevertheless, Walker shows Heaviside’s vital influence in defining the attributes of the ionosphere. Such is the state of progress in Walker’s book that the reader quickly accepts the special and complete nature of the individuals who kept adding to our knowledge of the Earth’s atmosphere.

This inclusion of the experimenters, together with their results, makes the book. But, given this focus, the book leans more to the pleasant than technical side of things. Walker seems only to include details of our atmosphere as learned through her chosen individuals. For example, Lavoisier isolated and named the constituent “oxygene”. Yet, aside from a few other elements or compounds, no other constituent parts or their discoverers get identified. Further, the choice of topics, though always fascinating, doesn’t necessarily flow. Properties of the atmosphere begin the book. Later, the reader learns of glaciation and carbon dioxide concentration, then the reason for the direction of trade winds, and finally the effects of the ionosphere on the propagation of radio waves. Accompanying these are tales of the Titanic, Sputnik and global warming. From this, the book altogether feels distinctive but it doesn’t have a comprehensive feel.

Nevertheless, Walker has written a very pleasant book to read. It’s as if she’s collected notes while popping all about in a little time machine. With this, both history and science take on a fascinating and very human dimension. For those who are fascinated by science but have long ago given up on science texts as being far too boring, then this book should easily re-awaken their fascination. Walker’s special rendition of unique, almost crazy individuals who valued knowledge much more than tradition is particularly captivating. Her solid basis on facts is assuring. Her choice of topic, that so often resides in today’s news headlines, proclaims its immediacy. There’s no doubt the average reader will have an entertaining and instructive time with this book.

Combining a famous scientist’s personal characteristics, together with an explanation of their discoveries, brings these great individuals back from the halls of the renown and into the common theatre of life. Gabrielle Walker’s book An Ocean of Air – Why the Wind Blows and Other Mysteries of the Atmosphere does just this in rekindling many great discoveries. As well, she includes details of the special characteristics of our atmosphere to remind us of the debt we owe these people in their investigation of the unseen air.

Read more reviews or purchase a copy online from Amazon.com.

Podcast: How to Win a Nobel Prize

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Just a couple of shows ago, we showed you how to get a career in astronomy. Now that you’ve got your career in astronomy, obviously the next goal is to win a Nobel prize. We’re here at the American Astronomical Society meeting in Austin, which is just one tiny step that a person has to take before you get that Nobel prize. Before you get that call in the middle of the night from Sweden, you’re going to need to come with an idea, do some experiments, write a paper, get published and a bunch of other stuff. This week, we’ll tell you all about it.

Click here to download the episode

How To Win a Nobel Prize – Show notes and transcript

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

Make Room at the Moon

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Lunar orbit is getting to be a busy place, with several different countries sending spacecraft to the moon. Currently orbiting the Moon are Japan’s Kaguya (also known as SELENE) spacecraft, which has been sending back 3-D movies of the lunar surface, and China’s Chang-e 1, which will gather information on the Moon’s chemical composition with its various cameras, spectrometers and other scientific equipment. In addition, two new missions to the moon will launch this year: India’s Chandrayaan-1 and NASA’s Lunar Reconnaissance Orbiter.

Chandrayaan, which means “journey to the moon” in Hindi, will study the moon at many wavelengths, from X-ray, visible and near-infrared to microwave. It will orbit the moon at just 100 km above the surface. The mission is scheduled to launch on April 9.

“The low orbit will give us really high resolution data,” says Detlef Koschny, Chandrayaan project scientist. The principal mission objective is to map the Moon’s surface in unprecedented detail. Current lunar maps show detail from 30 – 100 meters across. Chandrayaan will produce maps with a resolution of between 5 and 10 meters across the whole surface of the moon.

The European Space Agency (ESA) is collaborating with Indian Space Research Organization (ISRO) for the Chandrayaan-1 mission. A Compact Imaging X-ray Spectrometer will produce x-ray spectroscopic mapping of the moon, and the Infrared Spectrometer will observe the Moon’s chemical composition. Another ESA instrument is the Sub-keV Atom Reflecting Analyzer, which will study the interaction between electrically charged particles from the solar wind and Moon’s surface.

Eight other instruments complete the suite of science instruments, including a 29-kg landing probe which will be dropped onto the Moon’s surface at the beginning of the mission to conduct investigations.

Meanwhile, the Lunar Reconnaissance Orbiter (LRO) is currently undergoing testing at Goddard Spaceflight Center to get ready for its launch on October 28 of this year. LRO will spend at least a year mapping the surface of the moon. Data from the orbiter will help NASA select safe landing sites for astronauts, identify lunar resources and study how the moon’s environment will affect humans.

Engineers at Goddard are building the orbiter and testing spacecraft components to ready them for the harsh environment of space. After a component or entire subsystem is qualified, it is integrated into the LRO spacecraft. The core suite of avionics for the orbiter is assembled and undergoing system tests.

“This is a major milestone for the mission,” said Craig Tooley, LRO project manager at Goddard. “Our team has been working nearly around the clock to get us to this point. Reaching this milestone keeps us on the path to sending LRO to the moon later this year.”

Once fully integrated, the spacecraft will ship to NASA’s Kennedy Space Center, Florida in August in preparation for launch. The orbiter and the Lunar Crater Observation and Sensing Satellite (LCROSS) will launch aboard an Atlas V rocket. LCROSS will study the poles of the moon to confirm the presence or absence of water ice in a permanently shadowed craters. The trip to the moon for the spacecraft will take approximately four days. The Lunar Reconnaissance Orbiter initially will enter an elliptical orbit, also called the commissioning orbit. Once moved into its final orbit, a circular polar orbit approximately 31 miles above the moon, the spacecraft’s instruments will map the lunar surface.

Original News Sources: Chandrayaan Press Release, LRO press release

MESSENGER and other Significant Mission Events in 2008

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Today, the MESSENGER spacecraft will perform a significant task in its mission by making its first flyby of Mercury (see more info below). Additionally, other spacecraft that are out doing their jobs in various locations of our solar system will have significant mission events occur in 2008. Let’s take a look at the big events coming up this year.

January 14: MESSENGER Flyby of Mercury

Messenger, the MEercury Surface Space ENvironment GEochemistry and Ranging spacecraft, will be the first spacecraft to visit Mercury in almost 33 years. It will explore and take close-up images of parts of the planet that we’ve never seen before. This is the first of three flybys of Mercury the spacecraft will take before settling into orbit in 2011. MESSENGER’s cameras and other instruments will collect more than 1,200 images and make other observations during this approach, encounter and departure. The closest approach of the flyby will occur at 19:04:42 UTC (2:04:42 EST), but mission managers said pictures from the event may not be released for up to a week.

March 12: Cassini flies through the plume of Enceladus’ geyser

The Cassini spacecraft will fly extremely close to Saturn’s moon Enceladus at an altitude of only 23 km (14 mi), and actually fly through the plume of an active geyser on the moon’s south pole. How such a cold moon could host an area warm enough to have erupting water vapor is a mystery. Scientists are pondering if Enceladus has active ice volcanism, and if so, is it due to ice sublimating, like a comet, or due to a different mechanism, like boiling water as in Old Faithful at Yellowstone. This flyby will help answer those questions.

Cassini will also have several relatively close flybys this year of the moon Titan. The flybys will occur on Feb. 22, March 25, and May 12.

May 25: Phoenix lands on Mars

Phoenix will land in the north polar region of Mars and will help characterize the climate and geology of the Red Planet, as well as possibly determine if live ever arose on Mars. Pursuing NASA’s “Follow the Water” strategy, the lander will dig through soil to reach water ice with its robotic arm and perform numerous scientific experiments. Phoenix launched on Aug. 4, 2007. University of Arizona’s Phoenix page

September 5: Rosetta flyby of Asteroid Steins

The Rosetta spacecraft is on its way to orbit comet 67P Churyumov-Gerasimenko in 2014, but in the meantime it will pass by Asteroid 2867 Steins. During the flyby, Rosetta will study Steins to determine and characterize the asteroid’s surface composition and morphology. Asteroid Steins is roughly 10 km in diameter.

2008 Launch Calendar and Preview

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2008 will be a busy year throughout the world and our solar system as various robotic and human missions are slated to begin their journeys of exploration and science. One of the most exciting and nail biting times of a mission is the launch, and following is a list of mission launches that will occur in 2008. Included is information about each mission and links to mission homepages, as well as launch locations, just in case you’ll be in the area. Of course, as the year rolls along, we’ll be covering each of the missions in Universe Today.

2008 Launches:

All launch dates are subject to change. The launches listed are non-military scientific robotic and human missions.

January 30: THEOS (Thailand Earth Observing System) (GISTDA)
Launch site: Yasny, in Orenburg Oblast, Russia Dombarovsky Cosmodrome, Russia
Launch vehicle: Kosmotras Dniepr rocket
THOES will be used for cartography, agricultural monitoring, forestry management, coastal zone monitoring and flood risk management in Thailand. The spacecraft was built by EADS Astrium in France.

Feb. 5: Progress 28P (Roskosmos)
Launch site: Baikonur Cosmodrome, Kazakhstan
Launch Vehicle: Soyuz
The 28th Progress cargo delivery ship to the International Space Station (ISS).

Feb. 7: Space Shuttle Mission: STS-122 (NASA)
Launch Site: Kennedy Space Center – Launch Pad 39A
Launch Vehicle: Space Shuttle Atlantis
STS-122 will deliver the Columbus European Laboratory Module to the ISS, and is the twenty-fourth mission to the space station.

February 22: ESA’s ATV Jules Verne (ESA)
Launch site: ELA-3, Kourou, French Guiana
Launch vehicle: Ariane 5
The European Space Agency’s first Automated Transfer Vehicle “Jules Verne� will dock with the ISS to bring supplies and equipment to the station.

Mid to Late March: Space Shuttle Mission: STS-123 (NASA)
Launch Vehicle: Space Shuttle Endeavour
Launch Site: Kennedy Space Center – Launch Pad 39A
Mission STS-123 will deliver the pressurized section of the Kibo Japanese Experiment Logistics Module (ELM-PS) on the twenty-fifth mission to the ISS.

April 8: Soyuz ISS 16S (Roskosmos)
Launch site: Baikonur Cosmodrome, Kazakhstan
Launch vehicle: Soyuz
Flight of the manned Soyuz TMA-12 spacecraft to the International Space Station with members of the Expedition 17 crew. The capsule will remain at the station for about six months, providing an escape vehicle for the crew.

April 9: Chandrayaan-1 (ISRO)
Launch site: Satish Dhawan Space Centre, India
Launch vehicle: India’s PSLV (Polar Satellite Launch Vehicle)
India’s lunar orbiter mission will create a 3-D atlas of the moon, as well as conduct chemical and mineral mapping of the entire lunar surface. NASA’s Chandrayaan webpage

April 24: Space Shuttle Mission STS-124 (NASA)
Launch Site: Kennedy Space Center – Launch Pad 39A
Launch Vehicle: Space Shuttle Discovery
Space Shuttle Discovery on mission STS-124 will transport the Kibo Japanese Experiment Module – Pressurized Module (JEM-PM) and the Japanese Remote Manipulator System (JEM-RMS) to the International Space Station.

May 14: Progress 29P (Roskosmos)
Launch site: Baikonur Cosmodrome, Kazakhstan
Launch Vehicle: Soyuz
The 29th Progress cargo delivery ship to the International Space Station (ISS).

May 15: GOCE satellite (Gravity field and steady state Ocean Circulation Explorer)(ESA)
Launch site: Plesetsk, Russia
Launch vehicle: Rokot / Briz KM
GOCE will measure the Earth’s gravity field and model the geoid, or hypothetical surface of the Earth, with extremely high accuracy and spatial resolution. It also will provide insight into the physics and dynamics of the Earth’s interior, such as volcanism and earthquakes.

May 16: GLAST (Gamma-ray Large Area Space Telescope) (NASA)
Launch Site: Cape Canaveral Air Force Station – Launch Complex 17 – Pad 17-B
Launch Vehicle: United Launch Alliance Delta II
GLAST the will have the ability to detect gamma rays in a range of energies from thousands to hundreds of billions of times more energetic than the light visible to the human eye. Radiation of such magnitude can only be generated under the most extreme conditions, thus GLAST will focus on studying the most energetic objects and phenomena in the universe, such as black holes, gamma ray bursts, neutron stars and cosmic rays. GLAST follows in the footsteps of the Compton Gamma Ray Observatory.

June 15: OSTM/Jason 2 (Ocean Surface Topography Mission)
Launch Site: Vandenberg Air Force Base – Launch Pad SLC-2
Launch Vehicle: United Launch Alliance Delta II
This will be a follow-on to the Jason mission to measure sea surface height and determine the variability of ocean circulation at decadal time scales with combined data from the Topex/Poseidon mission and Jason . This is a joint U.S., Canadian and European project.

July 15: IBEX (Interstellar Boundary Explorer)
Launch Site: Reagan Test Site, Kwajalein Atoll
Launch Vehicle: Orbital Sciences Pegasus XL Rocket
IBEX’s science objective is to discover the global interaction between the solar wind and the interstellar medium. It will take a set of global energetic neutral atom images to determine the strength and structure of the termination shock, and study the properties of the solar wind flow beyond the termination shock and in the heliotail.

July 20: GOES-O Geostationary Operational Environmental Satellite
Launch Site: Cape Canaveral Air Force Station – Launch Complex 17
Launch Vehicle: United Launch Alliance Delta IV
NASA and the National Oceanic and Atmospheric Administration (NOAA) are actively engaged in a cooperative program, the multimission series N-P. This series will be a vital contributor to weather, solar and space operations, and science. The weather satellite will orbit 22,300 miles above the planet to monitor conditions across the U.S.

July 31: HerschelPlanck (ESA)
Launch site: CSG, Kourou, French Guiana
Launch vehicle: Ariane 5
One rocket will launch two different spacecraft, the Herschel infrared space observatory and the Planck mission to study the cosmic microwave background radiation. Herschel is a 3.5 meter diameter reflecting telescope with instruments cooled to close to absolute zero to observe at wavelengths that not been previously explored. After a four-month journey from Earth, Herschel will spend at least three years in orbit around the second Lagrange point of the Sun-Earth system. Planck will image the anisotropies of the Cosmic Background Radiation Field over the whole sky.

Aug. 7: Space Shuttle Mission: STS-125 (NASA)
Launch Site: Kennedy Space Center – Launch Pad 39A
Launch Vehicle: Space Shuttle Atlantis
Space Shuttle Atlantis will fly seven astronauts into space for the fifth and final servicing mission to the Hubble Space Telescope. During the 11-day flight, the crew will repair and improve the observatory’s capabilities through 2013.

Aug. 12: Progress 30P (Roskosmos)
Launch site: Baikonur Cosmodrome, Kazakhstan
Launch vehicle: Soyuz rocket
The 30th Progress cargo delivery ship to the International Space Station.

Sept. 18: Space Shuttle Mission STS-126 (NASA)
Launch Site: Kennedy Space Center – Launch Pad 39A
Launch Vehicle: Space Shuttle Endeavour
ISS assembly flight ULF2 will deliver a Multi-Purpose Logistics Module to the International Space Station.

Oct. 12: Soyuz ISS 17S (Roskosmos)
Launch site: Baikonur Cosmodrome, Kazakhstan
Launch vehicle: Soyuz
The manned Soyuz TMA-13 spacecraft flies to the International Space Station with members of the Expedition 18 crew. The capsule will remain at the station for about six months, providing an escape vehicle for the crew

October TBD: SMOS (Soil Moisture and Ocean Salinity) & Proba-2 microsatellite (ESA)
Launch site: Plesetsk, Russia
Launch vehicle: Rokot
SMOS will measure microwave radiation emitted from the Earth’s surface at L-band (1.4 GHz) using an interferometric radiometer. Proba-2 is a technology demonstration satellite.

Oct. 28: LRO (Lunar Reconnaissance Orbiter) & LCROSS (Lunar Crater Observation and Sensing Satellite) (NASA)
Launch Site: Cape Canaveral Air Force Station – Launch Complex 41
Launch Vehicle: United Launch Alliance Atlas V
LRO will spend at least a year mapping the surface of the moon to help select safe landing sites for astronauts, identify lunar resources and study how the moon’s environment will affect humans. LCROSS will study the poles of the moon to confirm the presence or absence of water ice in a permanently shadowed craters.

Dec 1: SDO (Solar Dynamics Observatory) (NASA)
Launch Site: Cape Canaveral Air Force Station – Launch Complex 41
Launch Vehicle: United Launch Alliance Atlas V
SDO will help to understand the Sun’s influence on Earth and Near-Earth space by studying the solar atmosphere on small scales of space and time and in many wavelengths simultaneously. This is the first Space Weather Research Network mission in the Living With a Star Program of NASA.

Dec 15: OCO (Orbiting Carbon Observatory) (NASA)
Launch Site: Vandenberg Air Force Base, California – Launch Pad SLC 576-E
Launch Vehicle: Orbital Sciences Taurus Rocket
OCO will collect precise global measurements of carbon dioxide (CO2) in the Earth’s atmosphere to improve our understanding of the natural processes and human activities that may have an influence on this greenhouse gas. OCO is a new Earth orbiting mission sponsored by NASA’s Earth System Science Pathfinder Program.

Radioactive Hot Spots on Earth’s Beaches May Have Sparked Life

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We’ve heard about life being created in a puddle of primordial chemical soup, sparked by lightning strikes, or organic molecules falling to Earth from comets or planets, such as Mars. But now, there is an alternative. Early Earth was radioactive; the Moon also had a lower orbit, generating strong tidal forces. Due to the close proximity to abundant water, radioactive beaches may have possessed all the essential ingredients for organic compounds, and eventually life, to thrive.

Research by the University of Washington, Seattle, suggests that perhaps the highly radioactive environment of Earth some 4 billion years ago may have been the ideal time for life to form. The orbit of the Moon also had a part to play in this offbeat theory.

Through strong tidal forces by a Moon that orbited far closer to the Earth than it does today, radioactive elements accumulated on the beaches could be gravitationally sorted. The chemical energy in these beach hot spots was probably high enough to allow self-sustaining fission processes (which occurs in natural concentrations of uranium). The main product from fission is heat, therefore powering chemical processes and the generation of organic, life-giving compounds.

“Amino acids, sugars and [soluble] phosphate can all be produced simultaneously in a radioactive beach environment.” – Zachary Adam, an astrobiologist at the University of Washington Seattle.

This is a hard theory to understand, it is well known that radioactivity breaks down organic molecules and causes a whole host of problems for us carbon-based creatures. But in the early Earth, devoid of plants and animals, radioactive processes may have provided energy for life to begin in the first place.

This theory also partially explains why life may be a very rare occurrence in the universe: there must be the correct concentration of radioactive elements, on the surface of a water-dominated developing planet, with tidal forces supplied by a closely orbiting stellar body. The Earth may, after all, be unique.

Source: Telegraph.co.uk

Red Dwarfs Have Teeny Tiny Habitable Zones

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As space telescopes get larger and more sensitive, the search for Earth-sized worlds surrounding other stars is about to get rolling. But astronomers are going to need to know where to look. A team of researchers are working on a survey of nearby stars, calculating the habitable zones around them. When the search begins, astronomers are going to want to study these regions.

The Research Consortium on Nearby Stars (RECONS) is a survey using relatively small telescopes to study the habitable zones in the nearby stars. The team uses measurements of various stars brightnesses at optical and infrared wavelengths matched with their distances to get a sense of the stars’ habitability.

After gathering together a big list of potential candidate stars, the researchers can then categorize stars by size and temperature to find ones that might harbour life.

“Once we have good values for the temperatures and sizes of the nearby stars, we can estimate how hot planets will be at different distances from the stars,” explains Justin Cantrell, a Doctoral Candidate in Astronomy at Georgia State University. “We consider those stars that would have surface temperatures suitable for liquid water to be in the traditional habitable zone.”

The researchers were looking for habitable zones around red dwarf stars, which can be 50-90% smaller than the Sun and much cooler. The comprise 70% of the stars in the Milky Way, but they’re harder to spot because they put out less light.

They were surprised to learn that these red dwarf stars have tiny habitable zones. When they added up the habitable zones of 44 red dwarf stars nearby the Sun, they found they didn’t add up to equal the habitable zone of a single Sun like star.

So even though these red dwarfs are common, they’re not great candidates for life. Earth-type stars would need to be perfectly positioned in their tiny habitable zones to be good candidates for life.

Original Source: Georgia State University News Release

Gas Cloud on Collision Course with the Milky Way

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Don’t panic, but there’s a giant cloud of hydrogen gas on a collision course with the Milky Way. When it hits, 40 million years from now, it should generate vast regions of star formation. In fact, we don’t even need to wait; the leading edge of this gas cloud is already starting to interact with our galaxy. The fireworks are about to begin.

The cloud is called Smith’s Cloud, after the astronomer who discovered it in 1963. It’s 11,000 light-years long and 2,500 light-years wide, and contains enough hydrogen to make a million stars with the mass of the Sun.

Felix J. Lockman, of the National Radio Astronomy Observatory (NRAO) announced their latest observations of Smith’s Cloud at the Winter meeting of the American Astronomical Society in Austin, Texas. According to Lockman, the cloud is located 8,000 light-years from the Milky Way’s disk, and hurtling towards us at 240 km/second (150 miles/second).

“This is most likely a gas cloud left over from the formation of the Milky Way or gas stripped from a neighbor galaxy. When it hits, it could set off a tremendous burst of star formation. Many of those stars will be very massive, rushing through their lives quickly and exploding as supernovae. Over a few million years, it’ll look like a celestial New Year’s celebration, with huge firecrackers going off in that region of the galaxy,” Lockman said.

Until this latest research, astronomers were never sure if Smith’s Cloud was actually part of the Milky Way, being blown out of the galaxy, or something falling in.

Lockman and his colleagues made 40,000 individual pointings of the Green Bank radio telescope to pull together the data for their observations. This was necessary because the cloud is so vast.

“If you could see this cloud with your eyes, it would be a very impressive sight in the night sky,” Lockman said. “From tip to tail it would cover almost as much sky as the Orion constellation. But as far as we know it is made entirely of gas – no one has found a single star in it.”

Original Source: NRAO News Release

Fat Black Holes Can Lurk in Thin Galaxies

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Supermassive black holes are thought to lurk at the heart of most galaxies. Scientists have long believed that only the galaxies with thick central bulges could pull together enough mass for a supermassive black hole to form. But NASA’s Spitzer Space Telescope has turned up evidence that even skinny galaxies, with no central bulge, can still form these galactic monsters.

Astronomers used the Spitzer Space Telescope to survey 32 flat and bulgeless galaxies, and still turned up supermassive black holes in their central cores. This means that galaxy bulges aren’t necessary to build up these black holes; instead, the mysterious and invisible dark matter might be necessary to bring them together.

“This finding challenges the current paradigm. The fact that galaxies without bulges have black holes means that the bulges cannot be the determining factor, said Shobita Satyapal of George Mason University, presenting her research at the American Astronomical Society’s Winter meeting in Austin. “It’s possible that the dark matter that fills the halos around galaxies plays an important role in the early development of supermassive black holes.”

Seen from edge on, our own Milky Way’s bulge would be clearly visible, with the thin spiral arms trailing away to the sides. And researchers know we have a supermassive black hole. Researchers used to think there was a direct connection between the size of the bulge, and the mass of the black hole.

But in 2003, astronomers discovered a relatively lightweight black hole in a galaxy without a bulge. And then earlier this year, Satyapal and her team found another example of this bulgeless black hole.

Since bulges don’t seem to matter, Satyapal suggests that a galaxy’s dark matter halo is the deciding factor to determine how massive a black hole can get.

“Maybe the bulge was just serving as a proxy for the dark matter mass – the real determining factor behind the existence and mass of a black hole in a galaxy’s center,” said Satyapal.

Original Source: Spitzer News Release

MESSENGER Flyby of Mercury January 14th

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If you thought you were good at pool, think again: in a game of interplanetary billiards, the MESSENGER team has guided its spacecraft to pass by Mercury for the first time on Monday, after a dizzying path that has already taken it past the Earth once and Venus twice.

The MESSENGER (Mercury Surface, Space Environment, Geochemistry and Ranging) spacecraft will make its very first flyby of the planet on January 14th at 2:04 EST. It will pass within 200 kilometers (124 miles) of the surface. During the flyby it will be taking images and scientific measurements of the planet’s features.

The data it will be taking this time around will complement the measurements it will make when finally in orbit. MESSENGER will map the composition of Mercury’s surface, capture images at a resolution of hundreds of meters, and measure the structure of the planet’s magnetosphere and magnetic and gravitational fields.

Monday’s flyby will be the first time a spacecraft has visited Mercury in 33 years, since Mariner 10 did a series of flybys in the mid-1970s. During that mission, the spacecraft only imaged one hemisphere of the planet. MESSENGER will complete the picture, so to speak, by taking close-up images for the very first time of the other hemisphere.

The flyby will allow the spacecraft to map several features of Mercury that it will not be able to measure when in orbit, such as the magnetotail – the drawn out tail of the planet’s magnetosphere as it travels through space. It will also take over 1,200 images of the planet.

MESSENGER was launched in August of 2004, and has been making its way to Mercury by a number of different flybys of the Earth and Venus. The journey, though, is far from over. The spacecraft will make two more flybys of Mercury in October 2008 and September 2009, finally settling into orbit of the planet in March 2011.

It will then start a yearlong comprehensive study with its seven scientific instruments. When the journey is over, it will have traveled 4.9 billion miles (7.9 billion kilometers).

For more information and photos of the flyby, visit the official MESSENGER website.

Source: Johns Hopkins University Applied Physics Laboratory Press Release