August 20th Radio Show Online: More on Extra-Solar Planets

Available here is the August 20th episode of this radio show. In addition to usual Astronomy news and notes, I continue discussing the latest results concerning extrasolar planets - specifically measurements of their physical properties. A more detailed description will come soon, but in the meantime, hope you enjoy!

Description of August 13th Radio Show: Planet Formation and Extrasolar Planets

Below is the detailed description of August 13th edition of this radio show, already available here. On this program, I talked about:

• News: No, Phoenix Mars Lander has not detected life of Mars, even though one of the instruments on the Phoenix Mars Lander did detect a type of salt called perchlorate - a fuel source for some micro-organisms on Earth (link); ice in Martian soil may be preventing soil samples from entering the instruments on Phoenix Mars Lander; Cassini prepares to fly within 30 miles of geysers erupting on the surface of Saturn's moon Enceladus (link), initial data already received; Hubble Space Telescope celebrates its 100,000th orbit around the Earth by taking this image of a star forming region near star cluster NGC 2074 (link); instruments on the Hubble Space Telescope slated for repair during final servicing mission to occur in October (link) - astronauts interviewed August 11th; new book on how the Hubble Space Telescope got built recently published - "The Universe in a Mirror" by Robert Zimmerman; Interstellar Boundary Explorer mission undergoing testing of science instruments prior to its October 5th launch; bizarre object discovered by Dutch school teacher Hanny van Arkel in archived images of the night sky maintained by http://www.galaxyzoo.org (link); David Dunlap Observatory in Toronto sold to a developer; NASA's Aerospace Safety Advisory Panel releases annual report, available here; NASA readjusts time table of Constellation Program - the successor to the space shuttle; NASA awards prized at General Aviation Technology Challenge (link); NASA says farewell to this year's group of high school and college aged INSPIRE interns (link to INSPIRE program); NASA awards space radiobiology grants (link); Arizona students talked with astronaut Greg Chamitoff on International Space Station on August 15th.
• "Wednesday Morning Astronomers": An astronomer's opinion on the Astronomy content in Gregg Easterbrook's weekly column on ESPN's Page 2, available here - yes, it is extremely cheesy that Doritos broadcast an ad towards a nearby star, and I also hope they aren't offended by it. I also find it extremely disturbing that a NASA press release concerning a Spitzer observation of a star similar to that of the Sun was quashed for being "alarmist."
• Calendar of upcoming astronomical and science events in the greater Poughkeepsie/New York City area.
• Planet Formation: As explained previously no this program by Dr. Aki Roberge, planets are believed to form in the gas and dust disks left behind after a star forms. The starlight from the central star has a large effect on the gas and dust in this disk, possibly driving larger icy bodies out to the solar system before gas drag causes to circulate inwards. This can lead to the formation of organic molecules and water in this "proto-planetary" disk, as was recently observed (article). Planets in this disk are expected to grow from dust grains colliding and sticking together to form pebbles, which in turn stick together to from proto-planets, which then form planets. These dust grains and pebbles scatter the light from the central star, and this scattered light has been observed from the proto-planetary disk around KH 15B binary star system. As the planet grows, it carves out a gap in the disk detectable in radio observations of the gas and dust. This has been seen around a very young star, <100000 years old, HL Tau - implying that planets form very rapidly (link), as well as around older star AB Aurigae (link).
• Extra-Solar Planets: Currently, there are three major observational techniques to detect planets around other stars - the radial velocity method, which detects the motion of the central star caused by the gravitational pull of the planet, the transit method - which detects a decrease in the light from the central star caused by the planet passing between the Earth and the star, and microlensing technique - where the gravitational field of the planet bends the light from the star such that its brightness on Earth increases very quickly. All of these techniques require monitoring the properties of many stars at once. An upcoming project to do this using the radial velocity method is MARVELS. The radial velocity method requires precision measurements of the star's spectrum since the planet's signature is a periodic change in the central frequency of spectral lines. This requires very good calibration of the spectrometer, which might be easier and 100x more sensitive thanks to a new laser standard (link). There are many transiting planet searches being conducted on the ground and from space. One such satellite, the COROT mission, has discovered a planet orbiting a Sun-like star, though at an orbit very different from the Earth's (link). NASA has also directed a spacecraft which orbits comets to look for transiting planets in it's spare time, the EPOXI mission (link). A new detector possibly capable of detecting the transit from an Earth-size planet around another star is being developed in the UK called "RISE" (link). The microlensing technique has recently been used to detect a planet just three times the size of the Earth, the smallest extra-solar planet yet. SuperWASP, a transiting planet survey, has recently detecting 10 extra-solar planets with different sizes and orbits (link). A rocky planet has been inferred around another star due to its gravitational effect on a previous detected planet in this "solar system" - it has since been detected using the radial velocity method (link), as have three other Earth-like planets (link). Small planets have also been detected around small stars like brown dwarfs (link). It has been speculated the nearest star to the Sun, Alpha Centauri, might have Earth-like planets around it (link). Last, but not least, even though planetary nebulae have nothing to do with planets, a planet has been discovered inside one (link).

Sorry for the delay in posting this. Thank you very much for listening, hope you enjoyed it, and any and all feedback will be appreciated.

GLAST Press Conference

NASA's newest astronomical satellite, the currently named Gamma-ray Large Area Space Telescope (GLAST), has been up in space since June 11. It has finished it's engineering check-up and has now started taking science data. Tomorrow, NASA will hold a press conference at 1 PM ET, which will be stream live here. For more info on GLAST, check out this information page for media members, as well as my interviews with Dr. Julie McEnery, Dr. Dave Thompson, and Dr. Charles Meegan on the different instruments and scientific goals of GLAST. Last, but definitely not least, Dr. Steve Ritz - one of the top astronomers on GLAST - maintains a blog available here with the latest updates. Enjoy!

August 13th Radio Show: Planet Formation and Extrasolar Planets

Now available here is the August 13th episode of this radio show. In addition to the usual Astronomy news and notes, and the return of "Wednesday Morning Astronomer", I talked about the latest news and results concerning our understanding of how planets form and the properties of planets detected orbiting other stars. I hope to put a more detailed description online, soon. I promise.

Description of August 6th Radio Show: Star Formation and Brown Dwarfs

I know I already posted the August 6th radio show here, but below is a detailed description of what I actually talked about:

• Mars Phoenix Lander: The Thermal and Evolved Gas-Analyzer (TEGA) instrument detects water in sub-surface Martian ice it analyzed, mission also extended until September 30th (link); Microscopy, Electro-chemistry, and Conductivity Analyzer (MECA) instrument possibly detects perchlorate.
• News: Liquid lake discovered on Titan, believed to be full of ethane; European Space Agency (ESA) spacecraft Mars Express takes highest resolution image of Mars's moon Phobos ever (link); ESA spacecraft Rosetta starts tracking asteroid (2867) Steins in order to rendezvous with it on 5 September; book review in Nature on "The Black Hole War" by Leonard Susskind describing a debate between him and Stephen Hawking on the fate of black holes; NY Times article about new book "The Universe Mirror" by Robert Zimmerman about the challenges in getting the Hubble Space Telescope built and launched; congratulations to Mr. Enrico Saggese for being appointed head of the Italian Space Agency; congrats to Dr. Thomas B. Irvine for being appointed Deputy Associate Administrator of NASA's Aeronautics Research Mission Directorate; congratulation to the winners of NASA's first Aeronautics Scholarship competition - list of winners available here and more about this program available here; NASA unveils this webpage in honor of its 50th anniversary; NASA hosts an international meeting to discuss future lunar science missions, signs partnership agreement with University of Western Ontario; NASA's Lunar Reconnaissance Orbiter undergoes pre-launch testing at Goddard Space Flight Center; Solar Eclipse on morning of August 1 (link); NASA to broadcast highlights of its activity in HD on NASA TV.
• Calendar of upcoming Astronomy/science events in the greater New York City / Poughkeepsie Area.
• Star Formation: As described very well in an interview I did with Dr. Aki Roberge of NASA's Goddard Space Flight Center, stars form by the gravitational collapse of dense clumps (>100 of atoms per cubic cm) of material in molecular clouds, cold regions where atoms can stick together into molecules and dust grains (essentially, very large molecules with 100s of atoms stuck together). Therefore, the chemical composition of these molecular clouds are the building blocks of the chemicals we find in the Sun, Solar System, and on Earth. With radio telescopes, one can see spectral lines from these molecules, and in one molecular cloud, a primitive amino acid (acetonitrile) was discovered, while surveys for identifying other complicated molecules in molecular clouds are currently taking place (link). Miniature diamonds found inside meteorites can also form in these molecular clouds, and can be detected with the Spitzer Space Telescope. To determine how a molecular cloud breaks into dense clumps which will collapse into stars, it is important to know the distribution of material inside the molecular cloud. Since molecular clouds are extremely dense and cold, it is very hard to see into them because they absorb all the optical light behind them and don't emit much optical light of their own. However, molecular clouds scatter infrared light from stars behind them, and this scattered light can be observed, creating an effect called "cloud shine". Since denser regions scatter more light, the amount scattered light which one sees gives an estimate of the density. This approach is currently being applied to a large number of molecular clouds with ESO's New Technology Telescope and upcoming VISTA telescope. As clumps in the molecular cloud collapse into stars, these clumps can fragment, and the mass of these fragments are extremely important in determining the mass of the stars which form. Recent computer simulations by Dr. Krumholz and Prof. McKee of Princeton University suggest that, to form the most massive stars, the clump must have column density (density of material through the region, mass per unit area NOT mass per unit volumn) 1 gm / square centimeter, though this number depends on fraction of mass in elements heavier than H and He which are critical in the physics of how the gas increases in density by about a million times to become a star. Replicated this process on a computer is extremely difficult, and recently a new software code called "FEARLESS" has been developed to try and solve many of the problems (link). As the gas collapses into star, it doesn't collapse directly into a star but forms a disk of material which slowly moves inward to for the star. Recent observations of a forming star, DG Tau, has found collimated, fast moving material moving away from the central star which astronomer call a "jet". Many of these "jets" from forming star have been discovered, but the material in this one is so hot it produces X-rays that are absorbed by the material in the disk, possibly changing its chemical composition. Now, stars born at the same time, with the same mass, and out of the same material are expected to have identical properties. However, recent observations of a binary star system where one star passes in front of the other suggest that, despite having the same mass and age, they have different temperatures and radii which is extremely bizarre (link).
• Brown Dwarfs: Brown dwarfs are the least massive stars, only a few times more massive than Jupiter, and are believed to have too little mass to produce a hot core that fuses hydrogen into helium as out Sun does. As mentioned above, stars when they are form are often observed to power jets into their surroundings. Well, brown dwarfs were recently observed to do the same (link). Also, the coldest dwarf ever observed was recently detected, with a surface temperature of 350 Celsius, comparable to a pizza oven, and about 3x times colder than the surface of the Sun (link). Also, the mass and temperature of brown dwarfs orbiting each other have recently been measured, and differ from that predicted by models (link).

Sorry for the delay in posting this, and hope you enjoy. As always, any and all feedback will be very appreciated.

Partial Lunar Eclipse Saturday Night

This Saturday, some of the world has a chance to see a partial lunar eclipse which occurs when the Sun-Earth-Moon form a line, such that the Earth blocks sunlight from hitting the Moon's surface, causing it to go dark. It unfortunately won't be observable everywhere, so go here for more details as to where you can see it. Lunar eclipses can be quite pretty, so if you take any pictures and post them online, please leave the URL below. I'd love to see them!

Want to ask an astronaut a question?

Every week, NASA will be transmitting submitted question to astronaut Greg Chamitoff, currently on the International Space Station, who will record answers and send them back down to Earth. If you have a question for him, go here for details. He hopefully will return safely to Earth in November on the space shuttle Endeavor, so you have to submit you question before then. Good luck!

Perseid Meteor Shower

The Perseid meteor shower peaked last night / early this morning, and spaceweather.com has lots of amazing pictures of this event here. If you have your own pictures, please email me the URL or leave it below - I'd love to see them. And if you missed the meteor shower, don't worry you can still see some meteors for about another week and it should be back next year.

Hubble Space Telescope Competition

In honor of the Hubble Space Telescope completing its 100,000th orbit around the earth, hubblesite.org is sponsoring a raffle for a framing-worthy photography of this image of a star-forming region in the Large Magellanic Cloud taken by Hubble during this orbit. Good luck!

NASA Aeronautics Scholarship Program

Last year, NASA started a new scholarship program for undergraduate and graduate students, the winners of which were recently announced and can be viewed here. Congratulations to those who won, and for those interesting in trying in 2009, keep an eye on this webpage for forms and instructions. Good luck!

NASA 50th Anniversary Webpage

To commemorate it's 50th anniversary, defined by when Pres. Eisenhower signed a bill passed by Congress to create it, NASA has created this website which offers a tour of its major achievements and accomplishments - including a lot of neat multimedia features including archival footage of press conferences and interviews. Hope you enjoy!

August 6th Radio Show online: Star Formation and Brown Dwarfs

Now available here is the August 6th episode, where I talked about some interesting results concerning molecular clouds, star formation, and the brown dwarfs - very low mass "stars," too low to burn Hydrogen to Helium in their cores, which are believed to be a sort of transition object between stars and massive planets like Jupiter. I will post a more detailed synopsis later, as I'm currently at Marshall Space Flight Center for work.

Hope you enjoy and, as always, any feedback would be appreciated.

Solar Eclipse pictures

Last Friday, a Solar Eclipse was visible from northern Europe to China, and pictures of this events are available here courtesy of spaceweather.com. Enjoy!

July 30th Radio Show online: Mercury, Saturn, and the Outer Solar System

The July 30th radio show is now online and available here. This show marked the end of our trip through the Solar System, and I discussed the latest news concerning the innermost planet in the Solar System (Mercury), as well as one of the outer ones (Saturn), and recent measurements concerning the edge of the Solar System. In detail I covered:

• News: Thank you to Home Depot for donating a new and much-needed roof to the Custer Institute and Observatory; Phoenix Mars Lander producing 3D image of surrounding area (link,3D map); NASA starts funding a GPS program for the Moon (link); NASA invites media for a demo of Lunar Surface Manipulator concept on August 1st; NASA to hold media briefing for final Hubble servicing mission September 8-9; NASA and USDA sign an agreement for the USDA to conduct research on the International Space Station; NASA develops a new webpage to show the latest satellite imagery of fires on the Earth; NASA's Kennedy Spaceflight Center hosts a program for Florida high school students to work on challenges related to returning to the Moon; 2008 General Aviation Technology Challenge to be held August 4-10 in Santa Rosa, CA; NASA's 50th Anniversary honored at EAA AirVenture 2008 air show in Oshkosh, WI July 28 - Aug 3; NASA successfully tests a parachute designed to slow down the descent of the first-stage motor from the Ares I rocket, the successor to the space shuttle; congratulations to NASA's programmers on the Data-Parallel Line Relaxation and Adaptive Modified Gerchberg-Saxton Phase Retrieval programs for winning NASA's 2007 Software of the Year award; ongoing dispute between NSF and local residents concerning the Advanced Technology Solar Telescope to be located on top of Mauna Kea; editorial in July 23rd New York Times calling for development of solar power stations in space (link); positive movie review of WALL-E in July 24th edition of Nature magazine (I concur whole-heartedly); new exhibit at Museum of History of Science in Oxford, UK on Ferdinand Verbiest - court astronomer in China in the late 1600s; Perseid Meteor shower to peak on August 12th, expected to be a good one.
• Calendar of upcoming Astronomy events in the greater Poughkeepsie / New York City area
• Mercury: The closest planet to the Sun, it is one of the least studied planets in the Solar System because it is difficult to get space craft there (it takes a lot of fuel to decelerate a space craft launched from the Earth to get so close to the Sun. A space craft launched from the Earth will stay in the Earth's orbit if it doesn't fire rockets.) However, NASA recently launched a space craft called MESSENGER to study Mercury, and while it isn't in orbit around this planet just yet, on January 14th, 2008 it did it's first flyby during which it made some measurements that revealed some exciting new information about this planet that were summarized in the July 4th, 2008 edition of Science magazine. It discovered that the smooth surface in the Caloris Region basin is likely the result of volcanic activity on Mercury - long after such volcanism was expected to end; Mercury's magnetic field is generated by an active dynamo in the core, and not the remnant of a magnetic field formed earlier that was locked into its crust as previously thought; the cooling of Mercury's core shrunk so much that is caused huge wrinkles in the crust; and made the first observations of charged particles around Mercury kicked off the surface by the Solar Wind and sunlight (link 1, link 2, link 3).
• Saturn: In my opinion, one of the most beautiful planets in the Solar System with its extensive ring system and plentiful moons, Saturn and its surroundings have been studied extensively over the passed 4 years by the recently-extended Cassini spacecraft. Recent results include a temporal and altitude temperature variation in Saturn's atmosphere over its equator likely the equivalent of seasonal variations seen on Earth; a vortex over the south pole of Saturn; a secondary aurora on Saturn resulting from charged particles produced by volcanism on its moon (link); extremely powerful lightning on Saturn the source of observed bursts of radio emission seen from this planet (link); Saturn's innermost A-ring absorbs material ejected by geysers on Enceladus; the different velocity between the dust and gas ejected by the geysers on Enceladus (dust slower, gas faster) due to dust bouncing off the walls of the fractures in the surface of Enceladus from which they are produced (link); Cassini flyby through the material ejected from Enceladus detects organic compounds (link) - leading to suggestions that their might be life on this moon (link); common black coating found on the surface of many of Saturn's icy moons; variability and fine structure in Saturn's F-ring caused by moonlets in this ring (link); discovery of partial ring system around Saturn's moon Rhea (article); Saturn's moon Titan believed to more liquid hydrocarbons on its surface than present in the Earth (link) and has a rapidly changing rotation period likely the result of an internal water ocean.
• Pluto: It might not be classified as a planet any longer, but it is still an interesting object to study. NASA launched a space craft a few years ago called New Horizons to study it in detail, and it appears that Pluto's atmosphere will still be around when it arrives.
• Edge of the Solar System: The sun resides in the Milky Way, and one edge of the Solar System is defined where the solar wind - the stream of highly energetic particles produced in the Sun's corona - is decelerated by the surrounding interstellar medium. This region is called a "termination shock", since the wind is suddenly terminated there, about both Voyager spacecraft have crossed this boundary, Voyager 2 most recently on August, 31 2007. Voyager 2 crossed this shock at a distance very different than Voyager 1, suggesting that the termination shock is dented - possibly a result of the Milky Way's magnetic field. It was also able to make measurements of the density structure, composition, and magnetic field in this region - discovering that a lot of the energy in the solar wind is transferred to interstellar material ionized by solar wind particles (link). The STEREO spacecraft has also recently discovered high energy neutral particles from this region (link).

Thanks a lot for listening, hope you enjoyed, and any and all feedback is extremely appreciated.

Solar Sails

On the July 2nd radio show, I briefly mentioned that NASA was developing a prototype solar sail - a space craft which uses sunlight and the solar wind, the fast-moving flow of charged particles generated in the Sun's corona responsible for aurorae and satellite outages, and not propellants to move. Well, work is continuing on those prototypes, as you can read in this NASA Science article.

Goddard Space Flight Center

This February to April, I ran a series of interviews highlighting the wide diversity of research which occurs at Goddard Space Flight Center, a NASA facility in Greenbelt, MD. I should have done this much earlier, and I apologize for my tardiness, but the Goddard scientists who were kind of enough to appear on this program were:

• Dr. Jennifer Wiseman, who talked about ongoing and future research on star formation and extrasolar planets,
• Dr. Aki Roberge, who talked about specific problems in planet formation,
• Dr. Mark Clampin, who discussed the James Webb Space Telescope, NASA's successor to the Hubble Space Telescope,
• Dr. Gary Hinshaw, who talked about the Cosmic Microwave Background (CMB),
• Dr. Tod Strohmayer on what you can learn from the X-ray emission of accreting neutron stars,
• Dr. Neil Gehrels on the Swift telescope and Gamma-Ray Bursts
• Dr. Julie McEnery on the recently launched Gamma-ray Large Area Space Telescope (GLAST),
• Dr. Dave Thompson on the importance of multi-wavelength (radio to gamma-rays) observations in understanding the physics of the most energetic objects in the night sky, and
• Dr. Ann Hornschemier on Constellation-X, an idea for the generation of X-ray telescopes to succeed Chandra and XMM

Hope you enjoy. I personally think that these are some of the most interesting interviews I've done to date, and really encourage you to listen to them if the topics interest you - many of these astronomers are people who are at the top of the fields, and it was a pleasure for me to get to talk to them. Please leave any comments or questions you might have on the above web pages or down below. Thanks a lot for listening!