Posted on by Nancy Atkinson

Lunar Dust Transport Still a Mystery

Sketches made by the Apollo 17 crew of rays created by lofted lunar dust. Credit: NASA

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There are times when Moon appears to have a tenuous atmosphere of moving dust particles that are leaping up from and falling back to the Moon’s surface. First seen during the Surveyor and Apollo eras, these observations were completely unexpected, and scientists today are still trying to understand this phenomenon.

The first indication that something strange was going on with the lunar surface was in the 1960’s when cameras on the Surveyor spacecraft pointing towards the western horizon noticed a brighter hovering cloud that persisted for several hours.

“There are many other bits and pieces of observations of this kind,” said Dr. Mihaly Horanyi from the University of Colorado Boulder’s Laboratory for Atmospheric and Space Physics. “For example, the astronauts in the Apollo command modules that stayed in orbit about the Moon were hoping to take images of the dark sky, but of course there is scattered light from the dust in interplanetary space. But the brightness also appeared to follow the lunar surface, indicating that somehow dust is coming off the surface of the Moon.”

While astronauts from Apollo 8, 10, and 15 all reported such dust clouds, Apollo 17 in 1972 repeatedly saw and sketched what they called “bands,” “streamers” or “twilight rays” for about 10 seconds before lunar sunrise or lunar sunset.

Adding to the mystery, also on Apollo 17 was a dust detector placed on the surface by the astronauts, the Lunar Ejecta and Meteorite experiment, which was supposed to measure the high speed impacts of micrometeorites hitting the moon.

An Apollo 17 astronaut digs in the lunar regolith to study the mechanical behavior of moon dust. Credit: NAS

“Instead the measurements showed an increase of particle fluxes that went up a hundred fold when day turned to night and night turned into day at that location on the Moon,” Horanyi said.

“Every single one of these measurements has an alternate explanation somehow. But it seems that the whole body of these observations is best explained by recognizing that dust — even on an airless body — can move around and come to life.”

Even thought the Moon has no atmosphere, Horanyi said other processes that are likely related to the plasma and radiation environment of the Moon, “the electro-dynamic processes of the near surface lunar environment that can have strong enough electric fields and the surface can have enough electrostatic charges that can break the dust free and somehow shuffle it or move it around the surface.”

In other words, electrostatic charging of the lunar surface causes the dust to levitate, precipitated – somehow – by changes in sunlight.

Horanyi said this type of thing has been seen on other airless bodies, like on Mercury, comets and asteroids.
“For example, the near-landing on the asteroid Eros,”Horanyi said, “people noticed that the bottom of the craters are filled with fine dust, and there is not enough atmosphere, and certainly the body is too small have asteroid shakes – the asteroid version of earthquakes — so the possible transport that would trap or make dust pile up in some regions and move it from others, is most likely a plasma effect.”

Horanyi and other scientists have done lab experiments to try and replicate the lunar environment to see if a dust transport takes place.

“For the first set of experiments, imagine just a piece of surface with dust particles on it, and we shine light on this surface,” he said, “so that half is illuminated, half is not, pretending that there is a terminator region, that the sun is set on one side and is still shining light on the other. When you shine light on the surface with properties that are appropriate, you can emit photo electrons, but you only emit electrons from the lit side, and some of those electrons land on the dark side, — you have a positive charge surplus on the lit and a negative charge pile-up on the night side. Across a couple of millimeters you can easily generate a potential difference of maybe a watt, or a handful of watts, which translates actually as a small-scale, but incredibly strong electric fields. This could be like a kilowatt over a meter. But of course, it only exists over a sharp boundary, and that sharp boundary may be the key to understanding how you get dust moving to begin with.”

Horanyi said in the transient region where boundaries match up – lit and dark boundaries, or boundaries between where the surface is exposed to a plasma and where it is not – those sharp transitions could actually overcome adhesion between dust and the rest of the surface and start moving.

“And that’s where the story gets really interesting,” he said.

Hopefully, a new mission called LADEE (Lunar Atmosphere and Dust Environment Explorer) can help explain this mystery. It is slated to launch in 2013 and fly in low lunar orbit, as close to the surface as 30-50 km. Since NASA may not be sending astronaut to the Moon anytime soon, LADEE’s mission may now be a little different than previously thought, but it still has some important science to conduct.

It will carry three instruments, an infrared imager, a neutral mass spectrometer and a dust detector, which Horanyi is helping to build.

“That hopefully will be capable of measuring tiny, tiny, small particles that people argue are lofted from the surface,” Horanyis said. “And we hope that in combination these instruments might put an end to this argument that we’ve had since the early 1970’s whether dust is really actively transported and shuffled around on the lunar surface or not.”

Listen to a 365 Days of Astronomy podcast where Dr. Horanyi discusses the “Mysterious Moving Moon Dust.”

Posted on by Nancy Atkinson

Spectacular Night Launch for Soyuz Crew

Expedition 26 Flight Engineer Paolo Nespoli is seated in the Soyuz TMA-20 during its ascent to orbit. Nespoli and Flight Engineers Dmitry Kondratyev (at bottom) and Catherine Coleman (out of frame) launched on time to the International Space Station. Credit: NASA TV

With a spectacular night launch, the remainder of the Expedition 26 crew are now headed to the International Space Station on board a Soyuz TMA-20 spacecraft. NASA astronaut Cady Coleman, Russian cosmonaut Dmitry Kondratyev, and European Space Agency astronaut Paolo Nespoli lifted off from the Baikonur Cosmodrome in Kazakhstan at 2:09 p.m. EST Wednesday (1909 UTC and 1:09 a.m. local in Kazakhstan) on Wednesday, Dec. 16. Video from inside the capsule showed the crew riding comfortably during their ascent.


The trio are scheduled to dock to the station’s Rassvet docking port at 3:12 p.m EST onFriday, Dec. 17. Just in time for the holidays, they will join Expedition 26 Commander Scott Kelly and Flight Engineers Alexander Kaleri and Oleg Skripochka, already on board the ISS.

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You can watch the docking on NASA TV, beginning at 2:30 p.m. EST Coverage of the hatches opening and a welcoming ceremony aboard the station will begin at 5:30 p.m.

With a full compliment of six, Expedition 26 will be busy with scientific research and regular maintenance, but there will also be two Russian-segment spacewalks, and a variety of visiting resupply ships: a Japanese HTV cargo ship will arrive at the end of January, a Russian Progress re-supply ship will also come just before, hopefully, space shuttle Discovery arrives in early February — given the repairs of the external tank go well, and then a European Automated Transfer Vehicle, or ATV, arrives at the end of February.

After that, The shuttle Endeavour is scheduled launch in early April along with another Progress later that month.

Soyuz launch on Dec. 15, 2010. Photo credit: NASA/Carla Cioffi
Posted on by Nancy Atkinson

No Asteroid Particles Found in Second Hayabusa Compartment, But More in First

Artist concept of the Hayabusa spacecraft, which visited asteroid Itokawa in 2005 and returned samples to Earth in 2010. Credit: JAXA
Artist concept of the Hayabusa spacecraft, which visited asteroid Itokawa in 2005 and returned samples to Earth in 2010. Credit: JAXA

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No visible material from asteroid Itokawa was found inside the second compartment of a canister returned to Earth by the Hayabusa spacecraft. However, JAXA also announced that more micron-sized grains have been found in the first compartment, opened earlier this year. Reportedly, the first compartment has about 1,500 tiny particles, however some might be aluminum particles from the container itself. But about 20 grains were rocky or mineral-based. However, according to the Daily Yomiuri Online, no visible material was inside the second chamber, although further investigations of the second compartment will be done with a special microscope.

Hayabusa attempted to land on Itokawa twice. The cylindrical canister was divided into two chambers, and the second chamber was to contain material collected during the spacecraft’s first landing.
JAXA officials expect the second compartment to contain more microscopic particles from Itokawa since the first landing was longer than the second.

As far as the particles from the first chamber, several have been observed with an electron microscope, and according to UmannedSpaceflight.com, the “rocky” ones are 30 microns in size, with several larger ones are about 100 microns.

JAXA hopes to provide more insight on the nature of the grains by the end of the year.

Posted on by Nancy Atkinson

Near-Synchronous Explosions Connect Across the Vast Distances on the Sun

The solar corona, as observed by SDO’s AIA, for temperatures from 1 million degrees (blue), through 1.5 million (green), and 2 million (red), on 2010/08/01. This image serves as a background for magnetic field lines emerged onto the Sun. The locations of the major changes coincide with major solar activity on August 1, 2010. Credit: NASA, Lockheed Martin’s Solar and Astrophysics Laboratory.

For several decades, scientists studying the sun have observed solar flares that appear to occur almost simultaneously but originated in completely different areas on the Sun. Solar physicists called them “sympathetic” flares, but it was thought these near-synchronous explosions in the solar atmosphere were too far apart – sometimes millions of kilometers distant – to be related. But now, with the continuous high-resolution and multi-wavelength observations with the Solar Dynamics Observatory, combined with views from the twin STEREO spacecraft, the scientists are seeing how these sympathetic eruptions — sometimes on opposite sides of the sun — can connect through looping lines of the Sun’s magnetic field.

“The high-quality simultaneous data we received from SDO and the STEREO spacecraft, and our subsequent analysis, enable us to present unambiguous evidence that solar regions up to 160 degrees away are involved in defining the large-scale coronal field topology for flares and CMEs,” said Dr. Carolus Schrijver, who co-presented his team’s findings at the American Geophysical Union meeting in San Francisco.

“From the very first observations with SDO we saw small events seemed to impact large regions of the sun,” said Alan Title of the Solar and Astrophysics Lab at Lockheed Martin, and co-author of the paper, speaking at a press briefing, “but because we are scientists and are sometimes not very clever, we have to sometimes be beaten over the head, and went searching for some kind of causality. It has been in last couple of months where we worked out this picture together.”

The hammer on the head was a series of solar events that took place on August 1, 2010, where nearly the entire Earth-facing side of the Sun erupted in a tumult of activity, with a large solar flare, a solar tsunami, multiple filaments of magnetism lifting off the solar surface, radio bursts, and half a dozen coronal mass ejections (CMEs).

SDO, which launched in February of this year, along with the two Solar Terrestrial Relations
Observatory (STEREO) spacecraft — were ideally positioned to capture both the action on the Earth-facing side of the Sun, and most activity around the backside, leaving a wedge of only 30 degrees of the solar surface unobserved.

SDO’s Atmospheric Imaging Assembly (AIA) continuously observes the full solar corona and can trace perturbations over long distances, even if short-lived. The STEREO spacecraft were able to provide perspectives on activity on most of the “back side” of the Sun, and perhaps most importantly, SDO’s Helioseismic and Magnetic Imager (HMI) provided global magnetic field connections.

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As seen in the image above, the looping magnetic field lines connected the various events on August 1. Subsequent observations have revealed similar events.

“The magnetic field lines connect to other flares and other major events, with the eruptions and flares frequently coupled across large distances,” said Schrijver. “Previously, we had been looking for the cause of explosions just in the regions from where the explosions were coming from. That might be a good way to do it, but these observations show another aspect. If we wish to know why the flare goes off, we need to know not just properties of region but also a large fraction of the solar surface, in fact sometimes not even part we can see. So maybe reason we had difficulty figuring this out was that we were not seeing everything. We have to expand our view and look at everything.”

Title compared finally figuring out that these near synchronous events are related to how scientists finally figured out continental drift. “Everyone could see how Africa and South America could have once fit together, but no one could imagine the physical processes that could make that happen,” he said, “but all of a sudden someone measured it and figured out sea floor spreading and it made perfect sense.”

In response to a question of whether the magnetic field on the Sun has areas similar to fault lines on the Earth where magnetic lines emerge repeatedly, Schrijver told Universe Today that the magnetic field lines come from the deep within the solar interior, but why it chooses to emerge in certain areas repeatedly is a mystery. “There are successive nests, where they come up one after another, or preferred regions,” he said, but our details on this are fairly weak. Most of time we don’t know where magnetic field lines will emerge from the sun.”

Title said heliophysics research is still in its infancy, but the new resources SDO provides might bring a new era in this area of study.

“We’ve reached a turning point in our ability to forecast space weather,” said Title. “We now have evidence that multiple events can be triggered by other events that occur in regions that cannot be observed from Earth orbit. This gives us a new appreciation of why solar flare and CME predictions have been less than perfect. As we seek to understand the causes of eruptive and explosive events that will improve our ability to forecast space weather, it is clear that we must be able to analyze most of the evolving global solar field, if not all of it.”

Posted on by Tammy Plotner

Total Lunar Eclipse – December 21, 2010

Both lunar and solar eclipses can only occur when the Earth, Sun and Moon are directly aligned… and that alignment is about to happen just four days before Christmas! While the winter treat of totality will lend itself to North America, many other parts of the world will be able to enjoy a partial eclipse as well. Just remember your time zones and I’ll post specific times and locations just a little closer to the date. Right now, let’s learn more!

What is a partial eclipse or totality? When the Earth’s shadow engulfs the Moon, it is a lunar eclipse which occurs in two phases. The outer shadow cone is called the penumbra and the dark, inner shadow is called the umbra. A round body, such as a planet, casts a shadow “cone” through space. When it’s at Earth, the cone is widest at 13,000 kilometers in diameter, yet by the time it reaches the Moon it has narrowed to only 9,200 kilometers. Considering the distance to the Moon is 384,401 kilometers, that’s hitting a very narrow corridor in astronomical terms!

As a rule of thumb, remember that the Moon moves about its own diameter each hour, so the very beginning of a penumbral eclipse will be difficult to notice. Slowly and steadily, the coloration will begin to change and even inexperienced eclipse watchers will notice that something is different. The Moon will never completely disappear as it passes through the Earth’s umbral shadow cone, either. Thanks to our atmosphere bending the sunlight around us, it scatters the light and refracts the signature red and copper coloration we associate with lunar eclipse. Why? Just the small particles in our air – dust and clouds – the shorter wavelengths of light from the Sun are more likely to be scattered (in this case, red) and that’s what we see. Exactly the same reason sunset and sunrise appears to be red! If you’d like to dedicate a portion of your mind to science, then try judging the eclipse coloration on the Danjon scale. It was was devised by Andre Danjon for rating the overall darkness of lunar eclipses:

L=0: Very dark eclipse. Moon almost invisible, especially at mid-totality.
L=1: Dark Eclipse, gray or brownish in coloration. Details distinguishable only with difficulty.
L=2: Deep red or rust-colored eclipse. Very dark central shadow, while outer edge of umbra is relatively bright
L=3: Brick-red eclipse. Umbral shadow usually has a bright or yellow rim.
L=4: Very bright copper-red or orange eclipse. Umbral shadow is bluish and has a very bright rim.

Now we know what to plan for! Time to get your winter gear ready. Photographing or video taping an eclipse is easy – but remember if you live where it is very cold that your batteries will expire fast – so keep an extra set in a warm place next to your body.

Be sure to check back for specific times and locations here at UT on December 20th… and tell your family and friends about the very special Christmas present that’s coming your way!

Eclipse Images Courtesy of Doug Murray (top), Tom Ruen (bottom) and NASA (center illustration). We thank you!

Posted on by Nancy Atkinson

Hot Plasma Explosions Inflate Saturn’s Magnetic Field

This is an artist's concept of the Saturnian plasma sheet based on data from Cassini magnetospheric imaging instrument. It shows Saturn's embedded "ring current," an invisible ring of energetic ions trapped in the planet's magnetic field. Credit: NASA/JPL

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From a JPL press release:

A new analysis based on data from NASA’s Cassini spacecraft finds a causal link between mysterious, periodic signals from Saturn’s magnetic field and explosions of hot ionized gas, known as plasma, around the planet.

Scientists have found that enormous clouds of plasma periodically bloom around Saturn and move around the planet like an unbalanced load of laundry on spin cycle. The movement of this hot plasma produces a repeating signature “thump” in measurements of Saturn’s rotating magnetic environment and helps to illustrate why scientists have had such a difficult time measuring the length of a day on Saturn.

“This is a breakthrough that may point us to the origin of the mysteriously changing periodicities that cloud the true rotation period of Saturn,” said Pontus Brandt, the lead author on the paper and a Cassini team scientist based at the Johns Hopkins University Applied Physics Laboratory in Laurel, Md. “The big question now is why these explosions occur periodically.”

The data show how plasma injections, electrical currents and Saturn’s magnetic field — phenomena that are invisible to the human eye — are partners in an intricate choreography. Periodic plasma explosions form islands of pressure that rotate around Saturn. The islands of pressure “inflate” the magnetic field.

A new animation showing the linked behavior is can be seen at the Cassini website.

The visualization shows how invisible hot plasma in Saturn’s magnetosphere – the magnetic bubble around the planet — explodes and distorts magnetic field lines in response to the pressure. Saturn’s magnetosphere is not a perfect bubble because it is blown back by the force of the solar wind, which contains charged particles streaming off the sun.

The force of the solar wind stretches the magnetic field of the side of Saturn facing away from the sun into a so-called magnetotail. The collapse of the magnetotail appears to kick off a process that causes the hot plasma bursts, which in turn inflate the magnetic field in the inner magnetosphere.

Scientists are still investigating what causes Saturn’s magnetotail to collapse, but there are strong indications that cold, dense plasma originally from Saturn’s moon Enceladus rotates with Saturn. Centrifugal forces stretch the magnetic field until part of the tail snaps back.

The snapping back heats plasma around Saturn and the heated plasma becomes trapped in the magnetic field. It rotates around the planet in islands at the speed of about 100 kilometers per second (200,000 mph). In the same way that high and low pressure systems on Earth cause winds, the high pressures of space cause electrical currents. Currents cause magnetic field distortions.

A radio signal known as Saturn Kilometric Radiation, which scientists have used to estimate the length of a day on Saturn, is intimately linked to the behavior of Saturn’s magnetic field. Because Saturn has no surface or fixed point to clock its rotation rate, scientists inferred the rotation rate from timing the peaks in this type of radio emission, which is assumed to surge with each rotation of a planet. This method has worked for Jupiter, but the Saturn signals have varied. Measurements from the early 1980s taken by NASA’s Voyager spacecraft, data obtained in 2000 by the ESA/NASA Ulysses mission, and Cassini data from about 2003 to the present differ by a small, but significant degree. As a result, scientists are not sure how long a Saturn day is.

“What’s important about this new work is that scientists are beginning to describe the global, causal relationships between some of the complex, invisible forces that shape the Saturn environment,” said Marcia Burton, the Cassini fields and particles investigation scientist at NASA’s Jet Propulsion Laboratory, Pasadena, Calif. “The new results still don’t give us the length of a Saturn day, but they do give us important clues to begin figuring it out. The Saturn day length, or Saturn’s rotation rate, is important for determining fundamental properties of Saturn, like the structure of its interior and the speed of its winds.”

Plasma is invisible to the human eye. But the ion and neutral camera on Cassini’s magnetospheric imaging instrument provides a three-dimensional view by detecting energetic neutral atoms emitted from the plasma clouds around Saturn. Energetic neutral atoms form when cold, neutral gas collides with electrically-charged particles in a cloud of plasma. The resulting particles are neutrally charged, so they are able to escape magnetic fields and zoom off into space. The emission of these particles often occurs in the magnetic fields surrounding planets.

By stringing together images obtained every half hour, scientists produced movies of plasma as it drifted around the planet. Scientists used these images to reconstruct the 3-D pressure produced by the plasma clouds, and supplemented those results with plasma pressures derived from the Cassini plasma spectrometer. Once scientists understood the pressure and its evolution, they could calculate the associated magnetic field perturbations along the Cassini flight path. The calculated field perturbation matched the observed magnetic field “thumps” perfectly, confirming the source of the field oscillations.

“We all know that changing rotation periods have been observed at pulsars, millions of light years from our solar system, and now we find that a similar phenomenon is observed right here at Saturn,” said Tom Krimigis, principal investigator of the magnetospheric imaging instrument, also based at the Applied Physics Laboratory and the Academy of Athens, Greece. “With instruments right at the spot where it’s happening, we can tell that plasma flows and complex current systems can mask the real rotation period of the central body. That’s how observations in our solar system help us understand what is seen in distant astrophysical objects.”

Source: JPL

Posted on by Nancy Atkinson

String of Peaks Found on Titan Could be Cryovolcanoes

A potential cryovolcano – or ice volcano -- region on Saturn's moon Titan is shown in this image from NASA's Cassini spacecraft. This radar swath was laid on top of an image taken by Cassini's visual and infrared mapping spectrometer. Sotra Facula is located around 15 degrees south latitude, 40 degrees west longitude. Image credit: NASA/JPL-Caltech/USGS/University of Arizona

While icy cryovolcanoes on Titan have been theorized in the past, scientists didn’t have any hard evidence for them. But now, researchers from the Cassini mission have found proof that jumped out of their data in the form of 3-D mountain peaks. Using a new three-dimensional mapping technique, the team was able to create a realistic 3-D flyover of a region on Titan, above, where volcanic-like mountains appear to be lined up in a mountain range-type formation, complete with calderas and material flows. If cryovolcanoes do exist on Titan, they would potentially answer the question of why Titan has so much methane in its atmosphere.

“A combination of features makes us think we’ve found the best evidence so far for icy volcanoes on the moon Titan,” said Randy Kirk, a geophysicist with the U.S. Geological Survey and a member of the Cassini team. “Sotra Facular is a classic volcano with a crater on it and lava flows coming out of it.

Kirk presented the team’s findings at the American Geophysical Union conference in San Francisco.

Rather than erupting hot, molten rock, it is theorized that the cryovolcanoes of Titan would erupt volatiles such as water, methane, and ammonia. “A volcano is a place where material on the inside of a planetary body has gotten warm enough that it can erupt to the surface,” Kirk said. “When a body is made of ice and not rock, you get a cryovolcano.”

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Scientists have suspected cryovolcanoes might populate Titan, and the Cassini mission has collected data on several previous passes of the moon that suggest their existence. Kirk shared radar imagery from early in the Cassini spacecraft’s mission that showed Sotra Facular as bright spot on Titan’s equatorial sand sea, as seen above.

“There were thousands of places where bright ground peeks out of the dark places,” Kirk said, “and in particular we noticed a rose-type round feature, which we called The Rose, with a flows coming from it and we wondered if it was a volcano.”

Combining new data from Cassini’s radar instrument and the visual and infrared mapping spectrometer, the team was able to create the 3-D flyover movie, which shows two peaks more than 1,000 meters (3,000 feet) tall and multiple craters as deep as 1,500 meters (5,000 feet). It also shows finger-like flows. All of these are land features that indicate cryovolcanism.

“We were excited and quite happy when we saw the video,” Kirk told Universe Today at a press briefing on Tuesday. “There was a long time lapse between seeing the image of The Rose, and everybody was wondering if it was a volcano. When we finally managed to create the three dimensional from the topographic maps, I was shocked, and I made it from our own data set! I showed the video to team and they shared that reaction.”

Kirk said the flows were quite thin – thinner than anticipated at less than 100 meters (300 feet) thick — but there were more volcanoes in the same field as Sotra Facula than what the team expected.

In the video, mountains appear, with a huge pit like a volcanic calderas –“ a big bite out of the mountain,” as Kirk described it.

The topography in the video has been vertically exaggerated by a factor of 10. The false color in the initial frames show different compositions of surface material, as detected by Cassini’s visual and infrared mapping spectrometer. In this color scheme, dunes tend to look relatively brown-blue. Blue suggests the presence of some exposed ice. Scientists think the bright areas have an organic coating that hides the ice and is different and lighter than the dunes. The finger-like flows appear bright yellowish-white, like the mountain and caldera. The second set of colors shows elevation, with blue being lowest and yellow and white being the highest. Here, the dunes appear blue because they tend to occupy low areas.

This photograph shows a fissure and a row of craters in Laki, a volcanic region in the south of Iceland. Kirk said the region on Titan where potential cryovolcanoes have been found could look very similar to this landscape. Image credit: R. M. C. Lopes

Cryovolcanism could release methane from Titan’s interior, which explains Titan’s seemingly continuous supply of fresh methane in its atmosphere. Without replenishment, scientists say, Titan’s original atmospheric methane should have been exhausted long ago.

“One of mysteries on Titan is the source of methane,” said Linda Spilker, Cassini project scientist, “so cryovoclanoes offer the perfect opportunity to get methane from interior into the atmosphere of Titan.”

Kirk and his team calculated that a Sotra-sized volcanic eruption every 1,000 years would maintain the current level of methane in Titan’s atmosphere.

Jeff Kargel from the University of Arizona, who provided an independent assessment of the potential of cryovolcanoes on Titan, said that no one yet knows what the flows are made of from these volcanoes, but — providing a tantalizing visualization — said an ammonia-water cryolava with methane and carbon dioxide would make frothy, pumice-like deposits on Titan.

Kargel also added that the strongest evidence for cryovolcanoes on Titan is the topographical data that Kirk and his team have provided. “The strong evidence here is the is juxtaposition of the high and low topography in this region on Titan. There are very few tectonic activities that can produce comparable conic mountain like this.”

For more imagery from Kirk’s presentation and other presentations about the Saturn system at AGU, see this NASA webpage.

Posted on by Jon Voisey

Darwin vs. the Sun

The Age of the Sun and Darwinism

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Today, we take it for granted that the Sun produces energy via nuclear fusion. However, this realization only came about in the early 1900’s and wasn’t confirmed until several decades later (see the Solar Neutrino Problem). Prior to that, several other methods of energy production had been proposed. These ranged from burning coal to a constant bombardment of comets and meteors to slow contraction. Each of these methods seemed initially plausible, but when astronomers of the time worked out how long each one could sustain such a brightness, they came up against an unlikely opponent: Charles Darwin.

In a “Catholic Magazine and Review” from 1889, known as The Month, there is a good record of the development of the problem faced in an article titled “The Age of the Sun and Darwinism”. It begins with a review of the recently discovered Law of Conservation of Energy in which they establish that a method of generation must be established and that this question is necessarily entangled with the age of the Sun and also, life on Earth. Without a constant generation of energy, the Sun would quickly cool and this was known to be unlikely due to archaeological evidences which hinted that the Sun’s output had been constant for at least 4,000 years.

While burning coal seemed a good candidate since coal power was just coming into fashion at the time, scientists had calculated that even burning in pure oxygen, the Sun could only last ~6,000 years. The article feared that this may signal “the end of supplies of heat and light to our globe would be very near indeed” since religious scholars held the age of the Earth to be some “4000 years of chronological time before the Christian era, and 1800 since”.

The bombardment hypothesis was also examined explaining that the transference of kinetic energy can increase temperatures citing examples of bullets striking metal surfaces or hammers heating anvils. But again, calculations hinted that this too was wrong. The rate with which the Sun would have to accumulate mass was extremely high. So much so that it would lead to the “derangement of the whole mechanism of the heavens.” The result would be that the period of the year over the past ~6,000 years would have shortened by six weeks and that the Earth too would be constantly bombarded by meteors (although some especially strong meteor showers at that time lent some credence to this).

The only strong candidate left was that of gravitational contraction proposed by Sir William Thomson (later Lord Kelvin) and Hermann von Helmholtz in a series of papers they began publishing in 1854. But in 1859, Darwin published the Origin of Species in which he required an age of at least two billion years. Thomson’s and Helmholtz’s hypothesis could only support an age of some tens of millions of years. Thus astronomy and biology were brought head to head. Darwin was fully aware of this problem. In a letter to a friend, he wrote that, “Thomson’s views of the recent age of the world have been for some time one of my sorest troubles”.

To back the astronomers was the developing field of spectroscopy in which they determined that the sun and other stars bared a strong similarity to that of nebulae. These nebulae could contract under their own gravity and as such, provided a natural establishment for the formation of stars, leading gracefully into the contraction hypothesis. Although not mentioned in the article, Darwin did have some support from geologists like Charles Lyell who studied the formation of mountain ranges and also posited an older Earth.

Some astronomers attempted to add other methods in addition to gravitational contraction (such as tidal friction) to extend the age of the solar system, but none could reach the age required by Darwin. Similarly, some biologists worked to speed up evolutionary processes by positing separate events of abiogenesis to shave off some of the required time for diversification of various kingdoms. But these too could not rectify the problem.

Ultimately, the article throws its weight in the camp of the doomed astronomers. Interestingly, much of the same rhetoric in use by anti-evolutionists today can be found in the article. They state, “it is not surprising to find men of science, who not only have not the slightest doubt about the truth of their own pet theories, but are ready to lay down the law in the realms of philosophy and theology, in science which with, to judge from their immoderate assertions, their acquaintance is of the most remote? Such language is to be expected from the camp-followers in the army of science, who assurance is generally inversely proportional to their knowledge, for many of those in a word who affect to popularize the doctrine of Natural Selection.”

In time, Darwin would win the battle as astronomers would realize that gravitational contraction was just the match that lit the fuse of fusion. However, we must ask whether scientists would have been as quickly able to accept the proposition of stellar fusion had Darwin not pointed out the fundamental contradiction in ages?

Posted on by Jon Voisey

Qatar Led Team Discovers Exoplanet

When listing the major scientific powers, the tiny nation of Qatar is not one that generally comes to mind. However, a Qatar astronomer, partnered with teams from the Harvard-Smithsonian Center for Astrophysics (CfA) as well as other institutions has just discovered a new exoplanet, dubbed Qatar-1b.

The planet itself, is another in the class of hot Jupiters which are massive, gassy planets that orbit their stars extremely closely. It has an orbital period of 1.4 days and is expected to be tidally locked with its parent star, a K type star.

It was discovered by a set of wide angle cameras located in New Mexico which are capable of surveying a large number of stars at a single time. The goal was to find planets that eclipsed the parent star and would thus show regular variations in their light curve. Images taken from this system were then sent to teams working at Universities in St. Andrews, Leicester, and Qatar. These teams processed the images and narrowed the stars down to a list of a few hundred candidates to be studied further.

From there Dr. Khalid Al Subai as well as the Harvard CfA team used the Smithsonian’s Whipple 48-inch telescope to more accurately measure the transits as well as as their 60-inch telescope to make spectroscopic observations to weed out binary star systems. These observations confirmed the existence of the planet.

“The discovery of Qatar-1b is a great achievement — one that further demonstrates Qatar’s commitment to becoming a leader in innovative science and research,” said Al Subai. Indeed, in the past 15 years, Qatar has undergone a large revolution towards science and education. Many universities have begun to open remote campuses, including Carnegie Mellon and Texas A&M. A more comprehensive list of science initiatives can be found here.

“The discovery of Qatar-1b is a wonderful example of how science and modern communications can erase international borders and time zones. No one owns the stars. We can all be inspired by the discovery of distant worlds,” said CfA team member David Latham.