Space and astronomy news
The Earth seems like a safe place, most of the time. But we have evidence of terrible catastrophes in the ancient past, times when almost all life on Earth was wiped out in a geologic instant. What could have caused so much devastation? And will something like this happen again?
Click here to download the episode.
Or subscribe to: astronomycast.com/podcast.xml with your podcatching software.
This week’s Carnival of Space is hosted by Amy Teitel over at Vintage Space.
Click here to read the Carnival of Space #196.
And if you’re interested in looking back, here’s an archive to all the past Carnivals of Space. If you’ve got a space-related blog, you should really join the carnival. Just email an entry to [email protected], and the next host will link to it. It will help get awareness out there about your writing, help you meet others in the space community – and community is what blogging is all about. If you’ve got a space-related blog, you should really join the carnival. Just email an entry to [email protected], and the next host will link to it. It will help get awareness out there about your writing, help you meet others in the space community – and community is what blogging is all about. And if you really want to help out, sign up to be a host. Send an email to the above address.
[/caption]
Titan is a fascinating world to planetary scientists. Although it’s a moon of Saturn it boasts an opaque atmosphere ten times thicker than Earth’s and a hydrologic cycle similar to our own – except with frigid liquid methane as the key component instead of water. Titan has even been called a living model of early Earth, even insofar as containing large amounts of nitrogen in its atmosphere much like our own. Scientists have wondered at the source of Titan’s nitrogen-rich atmosphere, and now a team at the University of Tokyo has offered up an intriguing answer: it may have come from comets.
Traditional models have assumed that Titan’s atmosphere was created by volcanic activity or the effect of solar UV radiation. But these rely on Titan having been much warmer in the past than it is now…a scenario that Cassini mission scientists don’t think is the case.
New research suggests that comet impacts during a period called the Late Heavy Bombardment – a time nearly 4 billion years ago when collisions by large bodies such as comets and asteroids were occurring regularly among worlds in our solar system – may have generated Titan’s nitrogen atmosphere. By firing lasers into ammonia-and-water-ice material similar to what would have been found on primordial Titan, researchers saw that nitrogen was a typical result. Over the millennia these impacts could have created enough nitrogen to cover the moon in a dense haze, forming the thick atmosphere we see today.
“We propose that Titan’s nitrogen atmosphere formed after accretion, by the conversion from ammonia that was already present on Titan during the period of late heavy bombardment about four billion years ago.”
– Yasuhito Sekine et al., University of Tokyo, Japan
This model, if true, would also mean that the source of Titan’s nitrogen would be different than that of other outer worlds, like Pluto, and even inner planets like our own.
See the published results in the journal Nature, or read more on NewScientist.com.
Top image is a combination of a color-composite of Titan made from raw Cassini data taken on October 12, 2010 and a recolored infrared image of the comet Siding Spring, taken by NASA’s WISE observatory on January 10, 2010. The background stars were also taken by the Cassini orbiter. NASA / JPL / SSI and Caltech/UCLA. Edited by J. Major.
Note: the image at top is not scientifically accurate…the comet’s tail would be, based on the lighting of Titan, pointing more to the ten o’clock position as well as forward toward the viewer’s left shoulder. This would make it ‘look’ as if it were going the opposite direction though, away from Titan, and so I went with the more immediately decipherable version seen here. To see a more “realistic” version, click here.
[/caption]CAPE CANAVERAL – An Atlas V rocket carrying a highly sophisticated Space-Based Infrared System (SBIRS) GEO-1 satellite for the United States Air Force lifted off from the seaside Space Launch Complex-41 at 2:10 p.m. EDT on Saturday (May 7) into a gorgeous clear blue sky following a one day delay due to cloudy weather conditions surrounding the Florida space coast on Friday.
SBIRS GEO-1 is the maiden satellite in a new constellation of next generation military space probes that will provide US military forces with an early warning of missile launches that could pose a threat to US national security.
Credit: Alan Walters/awaltersphoto.com
The planned quartet of SBIRS satellites will deliver a quantum leap in infrared event detection and reporting compared to the current generation of orbiting Defense Support Program (DSP) satellites, according to Michael Friedman of Lockheed Martin in an interview with Universe Today at the Kennedy Space Center (KSC).
“The SBIRS GEO satellites will have both a scanning and starring sensor with faster revisit rates. They will be able to detect missile launches from the earliest stages of the boost phase and track the missiles to determine their trajectory and potential impact points,” said Friedman.
“SBIRS can see targets quicker and characterize the actual missile,’” explained Steve Tatum of Lockheed Martin at KSC.
In addition to providing improved and persistent missile warning capabilities in a global arena, SBIRS will simultaneously support missile defense, technical intelligence, battlespace awareness and defense of the US homeland.
“The 10,000 pound SBIRS GEO-1 satellite is the size of two Hummers. About 9000 people in 23 states were involved in constructing the satellite.”
“SBIRS GEO-2 will launch in the next year or two,” Friedman told me.
“GEO-2 is built and undergoing testing now,” added Tatum.
The $1.2 Billion SBIRS satellite was launched into a 22,000 mile high Geosynchronous orbit by the 189 foot tall Atlas V rocket. The Atlas rocket was in the 401 vehicle configuration with no solid rocket motors and includes a 4-meter diameter payload fairing.
The first stage was powered by the RD AMROSS RD-180 engine and the Centaur upper stage was powered by a single Pratt & Whitney Rocketdyne RL-10A engine.
The Atlas V rocket was built and launched by United Launch Alliance (ULA). This marks the 50th successful launch for ULA since the company was formed in December 2006.
“With this launch, ULA continues to demonstrate its commitment to 100 percent mission success,” said Michael Gass, ULA President and CEO. “This milestone is a testament to the dedicated employees that for every mission deliver excellence, best value and continuous improvement to our customers.”
Read my Atlas V SBIRS preview story here:
Atlas Rocket Poised for Blast Off with Advanced Missile Early Warning Spy Satellite
SBIRS GEO-1 Launch Photo Album by the Universe Today team of Ken Kremer and Alan Walters:
[/caption]
The Extrasolar Planets Encyclopedia counted 548 confirmed extrasolar planets at 6 May 2011, while the NASA Star and Exoplanet Database (updated weekly) was today reporting 535. These are confirmed findings and the counts will significantly increase as more candidate exoplanets are assessed. For example, there were the 1,235 candidates announced by the Kepler mission in February, including 54 that may be in a habitable zone.
So what techniques are brought to bear to come up with these findings?
Pulsar timing – A pulsar is a neutron star with a polar jet roughly aligned with Earth. As the star spins and a jet comes into the line of sight of Earth, we detect an extremely regular pulse of light. Indeed, it is so regular that a slight wobble in the star’s motion, due to it possessing planets, is detectable.
The first extrasolar planets (i.e. exoplanets) were found in this way, actually three of them, around the pulsar PSR B1257+12 in 1992. Of course, this technique is only useful for finding planets around pulsars, none of which could be considered habitable – at least by current definitions – and, in all, only 4 such pulsar planets have been confirmed to date.
To look for planets around main sequence stars, we have…
The radial velocity method – This is similar in principle to detection via pulsar timing anomalies, where a planet or planets shift their star back and forth as they orbit, causing tiny changes in the star’s velocity relative to the Earth. These changes are generally measured as shifts in a star’s spectral lines, detectable via Doppler spectrometry, although detection through astrometry (direct detection of minute shifts in a star’s position in the sky) is also possible.
To date, the radial velocity method has been the most productive method for exoplanet detection (finding 500 of the 548), although it most frequently picks up massive planets in close stellar orbits (i.e. hot Jupiters) – and as a consequence these planets are over-represented in the current confirmed exoplanet population. Also, in isolation, the method is only effective up to about 160 light years from Earth – and only gives you the minimum mass, not the size, of the exoplanet.
To determine a planet’s size, you can use…
The transit method – The transit method is effective at both detecting exoplanets and determining their diameter – although it has a high rate of false positives. A star with a transiting planet, which partially blocks its light, is by definition a variable star. However, there are many different reasons why a star may be variable – many of which do not involve a transiting planet.
For this reason, the radial velocity method is often used to confirm a transit method finding. Thus, although 128 planets are attributed to the transit method – these are also part of the 500 counted for the radial velocity method. The radial velocity method gives you the planet’s mass – and the transit method gives you its size (diameter) – and with both these measures you can get the planet’s density. The planet’s orbital period (by either method) also gives you the distance of the exoplanet from its star, by Kepler’s (that is Johannes’) Third Law. And this is how we can determine whether a planet is in a star’s habitable zone.
It is also possible, from consideration of tiny variations in transit periodicity (i.e regularity) and the duration of transit, to identify additional smaller planets (in fact 8 have been found via this method, or 12 if you include pulsar timing detections). With increased sensitivity in the future, it may also be possible to identify exomoons in this way.
The transit method can also allow a spectroscopic analysis of a planet’s atmosphere. So, a key goal here is to find an Earth analogue in a habitable zone, then examine its atmosphere and monitor its electromagnetic broadcasts – in other words, scan for life signs.
To find planets in wider orbits, you could try…
Direct imaging – This is challenging since a planet is a faint light source near a very bright light source (the star). Nonetheless, 24 have been found this way so far. Nulling interferometry, where the starlight from two observations is effectively cancelled out through destructive interference, is an effective way to detect any fainter light sources normally hidden by the star’s light.
Gravitational lensing – A star can create a narrow gravitational lens and hence magnify a distant light source – and if a planet around that star is in just the right position to slightly skew this lensing effect, it can make its presence known. Such an event is relatively rare – and then has to be confirmed through repeated observations. Nonetheless, this method has detected 12 so far, which include smaller planets in wide orbits such as OGLE-2005-BLG-390Lb.
These current techniques are not expected to deliver a complete census of all planets within current observational boundaries, but do offer us an impression of how many there may be out there. It has been speculatively estimated from the scant data available so far, that there may be 50 billion planets within our galaxy. However, a number of definitional issues remain to be fully thought through, such as where you draw the line between a planet versus a brown dwarf. The Extrasolar Planets Encyclopedia currently set the limit at 20 Jupiter masses.
Anyhow, 548 confirmed exoplanets for only 19 years of planet spotting is not bad going. And the search continues.
Further reading:
The Extrasolar Planets Encyclopedia
The NASA Star and Exoplanet Database (NStED)
Methods of detecting extrasolar planets
The Kepler mission.
[/caption]
Terby Crater, a 170-km-wide (100-mile-wide) crater located on the northern edge of the vast Hellas Planitia basin in Mars’ southern hemisphere, is edged by variable-toned layers of sedimentary rock – possibly laid down over millennia of submersion beneath standing water. This image (false-color) from the HiRISE camera aboard the Mars Reconnaissance Orbiter shows a portion of Terby’s northern wall with what clearly looks like liquid-formed gullies slicing through the rock layers, branching from the upper levels into a main channel that flows downward, depositing a fan of material at the wall’s base.
But, looks can be deceiving…
Dry processes – especially on Mars, where large regions have been bone-dry for many millions of years – can often create the same effects on the landscape as those caused by running water. Windblown Martian sand and repetitive dry landslides can etch rock in much the same way as liquid water, given enough time. But the feature seen above in Terby seem to planetary scientists to be most likely the result of liquid erosion… especially considering that the sedimentary layers themselves seem to contain clay materials, which only form in the presence of liquid water. Is it possible that some water existed beneath Mars’ surface long after the planet’s surface dried out? Or that it’s still there? Only future exploration will tell for sure.
“While formation by liquid water is one of the proposed mechanisms for gully formation on Mars, there are others, such as gravity-driven mass-wasting (like a landslide) that don’t require the presence of liquid water. This is still an open question that scientists are actively pursuing.”
– Nicole Baugh, HiRISE Targeting Specialist
Terby Crater was once on the short list of potential landing sites for the new Mars Science Laboratory (aka Curiosity) rover but has since been removed from consideration. Still, it may one day be visited by a future robotic mission and have its gullies further explored from ground level.
Click here to see the original image on the HiRISE site.
Image credit: NASA / JPL / University of Arizona
[/caption]
When last we checked in on Gliese 581d, a team from the University of Paris had suggested that the popular exoplanet, Gliese 581d may be habitable. This super-Earth found itself just on the edge of the Goldilocks zone which could make liquid water present on the surface under the right atmospheric conditions. However, the team’s work was based on one dimensional simulations of a column of hypothetical atmospheres on the day side of the planet. To have a better understanding of what Gliese 581d might be like, a three dimensional simulation was in order. Fortunately, a new study from the same team has investigated the possibility with just such an investigation.
The new investigation was called for because Gliese 581d is suspected to be tidally locked, much like Mercury is in our own solar system. If so, this would create a permanent night side on the planet. On this side, the temperatures would be significantly lower and gasses such as CO2 and H2O may find themselves in a region where they could no longer remain gaseous, freezing into ice crystals on the surface. Since that surface would never see the light of day, they could not be heated and released back into the atmosphere, thereby depleting the planet of greenhouse gasses necessary to warm the planet, causing what astronomers call an “atmospheric collapse.”
To conduct their simulation the team assumed that the climate was dominated by the greenhouse effects of CO2 and H2O since this is true for all rocky planets with significant atmospheres in our solar system. As with their previous study, they performed several iterations, each with varying atmospheric pressures and compositions. For atmospheres less than 10 bars, the simulations suggested that the atmosphere would collapse, either on the dark side of the planet, or near the poles. Past this, the effects of greenhouse gasses prevented the freezing of the atmosphere and it became stable. Some ice formation still occurred in the stable models where some of the CO2 would freeze in the upper atmosphere, forming clouds in much the same way it does on Mars. However, this had a net warming effect of ~12°C.
In other simulations, the team added in oceans of liquid water which would help to moderate the climate. Another effect of this was that the vaporization of water from these oceans also produced warming as it can serve as a greenhouse gas, but the formation of clouds could decrease the global temperature since water clouds increase the albedo of the planet, especially in the red region of the spectra which is the most prevalent form of light from the parent star, a red dwarf. However, as with models without oceans, the tipping point for stable atmospheres tended to be around 10 bars of pressure. Under that, “cooling effects dominated and runaway glaciation occurred, followed by atmospheric collapse.” Above 20 bars, the additional trapping of heat from the water vapor significantly increased temperatures compared to an entirely rocky planet.
The conclusion is that Gliese 581d is potentially habitable. The potential for surface water exists for a “wide range of plausible cases”. Ultimately, they all depend on the precise thickness and composition of any atmosphere. Since the planet does not transit the star, spectral analysis through transmission of starlight through the atmosphere will not be possible. Yet the team suggests that, since the Gliese 581 system is relatively close to Earth (only 20 lightyears), it may be possible to observe the spectra directly in the infrared portion of the spectra using future generations of instruments. Should the observations match the synthetic spectra predicted for the various habitable planets, this would be taken as strong evidence for the habitability of the planet.
Determining the chemical distribution of the galaxy is a tricky business. The ideal method is spectroscopy but since high quality spectroscopy takes bright targets, the number of potential targets is somewhat reduced. Stars seem like logical choices, but due to differential separation during formation, they don’t provide a true description of the interstellar medium. Clouds of gas and dust are the best choice, but must be illuminated by star formation. Another option is to search for newly formed planetary nebulae which are in the process of enriching the interstellar medium.
A new paper does just this, discovering a new planetary nebula in hopes of mapping the chemical abundance of the galaxy. The new nebula is almost the exact opposite direction of the galactic center when viewed from Earth. It lies at a distance of about 13 kpc (42,400 lightyears) from Earth making it one of the most distant planetary nebulae from the galactic center for which a distance has been determined and currently, the furthest with a measured chemical abundance.
The nebula was originally recorded on images taken by the INT Photometric Hα Survey (IPHAS) in 2003 but the automated program for detecting such objects initially missed the nebula due to its relatively large angular size (10 arcseconds). It was subsequently caught on visual inspection of the mosaics. Follow-up spectroscopy was conducted from 2005 to 2010 and reveal that the nebula is quite regular for planetary nebula, containing strong emission from hydrogen, nitrogen, oxygen, and silicon. The rate of expansion combined with its physical size suggests an age of nearly 18,000 years.
This newly discovered nebula provides a rare data point for the chemical abundance for the outer portions of the galaxy. While the galaxy is known to be enriched towards the galactic center, there has been debate about how quickly, if at all, it falls towards the galactic edge where star formation, and thus, enrichment, is less common. While there aren’t enough known nebulae to determine just yet (only four others are known at similar distances), this planetary nebula suggests that the abundance levels off in the galactic outskirts.
The authors also note that this nebula, as well as potentially the others, aren’t native to the Milky Way. They lie near a structure known as the Monoceros Ring, which is a stream of stars believed to be stretched out as the Milky Way devours the Canis Major Dwarf Galaxy.
[/caption]
Here’s a headline you don’t see too often: “Rubber Chicken Turned NASA Mission Mascot Embarks on a Flight to Space.” Seriously, this is a true story. If you’ve not heard of Camilla Corona, or Camilla SDO as she is sometimes called, you probably haven’t been paying attention to one of the most exciting current space missions, the Solar Dynamics Observatory. Camilla is virtually everywhere in the world of social media, and she travels around the country – and the planet – spreading the word about what’s going on with our Sun and how SDO is helping us learn more about it. As mission mascot, she is leading the way – and setting the bar pretty high for other NASA missions to follow – about how to get the public interested in space and science.
“People ask, ‘what does a rubber chicken have to do with a science mission?’ but as long as we get people’s attention, we can then divert it to what SDO does,” said Romeo Durscher, Camilla’s PR assistant and ‘bodyguard.’ “However, we didn’t know it would go this far when we started this.”
The story of Camilla goes back to the early days of SDO at Goddard Space Flight Center, when mission scientist Barbara Thompson introduced Camilla as something funny for the science team.
“Barbara was very persistent – she brought little Camillas and rubber chickens to all the science meetings to lighten up the room,” Durscher said.” The question always is, ‘why Camilla?’ and the official answer is because she is the same color as the sun. Over the years, Camilla has just become more and more integrated into the education and public outreach side of the mission.”
“Camilla started as an inter-office joke and soon became the mascot for the science side of the mission,” said Aleya Van Doren, the formal education lead for SDO. “It is not uncommon for someone who has been working on SDO for awhile to receive a rubber chicken as sort of a ‘you’ve earned your keep’ award. She’s a great moral booster for the science team, as well as being a wonderful ‘hook’ to get the public interested in the mission.”
Van Doren said the fun part is bringing Camila to public events or classrooms. “She is a great conversation starter with kids, especially with elementary children. Our main focus is getting the science out to the public, so whatever means we can use to draw in people’s interest and see the amazing things that SDO is doing, we consider it worthwhile.”
I’ve personally seen children — as well as adults — literally melt when meeting Camilla and get very excited about interacting with her.
As far as the public side of things, Van Doren said they are pleasantly surprised at the amount of attention her social media channels on Twitter and Facebook have been bringing to the mission.
“Romeo does a great job bringing her around to various places. Her schedule is quite full for a chicken. I would be really tired if I was that busy,” Van Doren said.
Which begs the question: just how many Camillas are there?
“That is a guarded secret,” Van Doren said, “but there is really only one official Camilla. We are very careful to make sure she is only in one place at a time. But sometimes airfare gets expensive, so she’ll have a body double in one place. Jet-setting around the country can sometimes be difficult.”
Durscher is the keeper of what is now the official Camilla, but confirmed that she does indeed have some body doubles. At first, it was easy to have Camilla be in several places at once. That was before she started wearing clothes.
“Our rubber chicken had the SDO mission pin on her left side, and that was Camilla,” Durscher said. “We had one at Goddard, one at Stanford University, and another at our education office, so there were several Camillas, and we had the story that she was travelling here and there, but now it gets a little more complicated.”
Cynthia Butcher, a fan of Camilla, knits specially made outfits for a rubber chicken, including a spacesuit, a Star Trek uniform, an “I Dream of Jeannie” outfit, and many more.
“Cynthia is a wonderful person, one of the first followers of Camilla on Twitter and Facebook,” Durscher said. “She really enjoyed what Camilla was doing, and said that Camilla should have a flight suit and that she would make her one. When we got the outfits, we were thrilled. But now we have to have a storyline for why we sometimes we might see Camilla without any clothes on – maybe the suit will be in the dry cleaning, or something.”
Camilla has met astronauts, trained at Johnson Space Center, attended World Space Week in Nigeria and a science fair in Malaysia, been on hand at many NASA Tweet-ups and launches, and even given a speech at the Smithsonain Ignite event at the Smithsonian Museum – well, actually Durscher ended up speaking for her, as Camilla lost her voice shouting at all the animals in the Washington DC Zoo the day before.
But Camilla’s main goal is to educate, inspire (especially to inspire girls to go into science and engineering) to build community and have fun — as well as bringing the beautiful, stunning and wonderful images and data from SDO into the classroom.
“We have lots of things teachers can use to educate their students about the Sun — hands-on experiments, beautiful images — and students can have the opportunity interact with mission scientists,” Durscher said.
But now Camilla embarks on what might be her greatest adventure ever. She is actually going to space. Camilla will be going to the edge of space in a weather balloon with a camera for the Camilla Space Weather Project.
“We are using that launch as the hook for new program we are doing to get the public interested in space weather forecasts,” said Van Doren.
Space weather refers to conditions on the Sun and in the solar wind that impact Earth’s atmosphere and can influence space and ground based technology and even human health.
“We have a page of a series of questions that people can go through to make a prediction of whether a space weather event is going to take place – such as the bright flares SDO has observed recently, and if those events will affect Earth, such as auroras being visible, or if it could cause any problems with satellites or related technology,” said Van Doren.
Launch is currently scheduled for this weekend, May 8 from the University of Houston central campus. Launch preparations begin at 10 AM, and will be webcast on UStream.
“We want to make sure that when Camilla launches it will be safe, so we’ve been having people make a space weather forecast and see whether or not it will be good conditions for launching to the upper atmosphere. Of course we don’t want Camilla to be bombarded with radiation, so classrooms have been making recommendations if this will be a good time to go or not,” Van Doren said.
Durscher said that as of Friday, the mission was go.
Camilla is not going to space alone. She’s traveling with Fuzz Aldrin from “Bears on Patrol” which provides US police officers with free teddy bears to use in cases involving small children, as well as a stuffed pig, Skye Bleu, the STEM (science technology engineering and math) outreach mascot for the American Institute of Aeronautics and Astronnautics (AIAA) and a patch to represent Smokey Bear.
“Our goal is to inspire the next generation of engineers, scientists and explorers,” Durscher said, “and we’ll make sure that Camilla and her crew will come back alive.”
Let’s hope so. Camilla has lots more work to do spreading the word about NASA, space and science.
[/caption]
CAPE CANAVERAL – An Atlas V rocket is poised to blast off today, May 6 , with the inaugural version of a new and highly advanced series of US spy satellites which will provide early warning of missile launches to US military forces. The Space Based Infrared Systems (SBIRS) GEO-1 satellite is set to liftoff Friday afternoon at 2:14 p.m. The launch window extends until 2:54 p.m. EDT.
The new satellite for the US Air Force is considered to be one of the highest priority military space programs. Covert intelligence satellites played a key role in hunting down Al Qaida terrorist leader Osama Bin Laden in the recent military strike by US forces inside Pakistan.
The Atlas V rocket with a Centaur upper stage was rolled out to the launch pad at Complex 41 on Wednesday morning and arrived at 11 a.m.
Twin track mobiles pushed the rocket and satellite combination about 1800 feet from the launch gantry – known as the Vertical Integration Facility – to the pad. Reporters and photojournalists including myself toured the pad for a photoshoot Wednesday afternoon.
The countdown has begun and clocks are ticking backwards for today’s planned liftoff.
Super-cold liquid oxygen and liquid hydrogen fuel begins to flow into the rocket shortly after noon.
The launch will be webcast by United Launch Alliance at this link:
Weather is the only concern and has deteriorated over the past few days. As of this morning the chances of acceptable weather has dropped to just 30% favorable due to the increasing threat of isolated clouds and rain showers. Weather conditions are currently overcast here in the vicinity of Cape Canaveral and are deteriorating with a good chance of thunderstorms. .
The SBIRS GEO-1 satellite will provide global , persistent, infrared surveillance capability to meet 21st century US military demands in four key areas including missile warning, missile defense, technical intelligence and battle space awareness.
Later this year, Atlas V rockets will launch two high profile NASA Planetary missions to space; the solar powered JUNO Jupiter Orbiter in August and the Mars Curiosity Rover in November.
