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During the last several years one of the most exciting aspects of astronomy has been data from two orbiting space observatories concerning planets which lie outside our solar system. The NASA space telescope Kepler discovers such planets by simultaneously measuring the light from thousands of stars for the faint dimming that occurs when a planet passes between the star and Kepler. The French satellite COROT (“COnvection ROtation and planetary Transits”) finds exoplanets by tracking the slight oscillations in distant stars caused by the gravitational tug of orbiting planets. The subtlety and elegant precision of both methods is astounding.
Sadly such astonishing engineering seems to have been near the edge of our technological abilities. Yesterday Kepler went into safe mode (a sort of automatic shut-down triggered by a crisis). Apparently a reaction wheel (a flywheel used to orient the spacecraft in relation to the stars) failed and Kepler can no longer be aimed properly. The orbital observatory initially had four reaction wheels—one of which was a spare– however the spare wheel failed in July of 2012 and at least three wheels are required to operate the satellite. If NASA cannot somehow reactivate the flywheel, then the mission is over.
Likewise on November 2, COROT suffered from a computer failure which made it impossible to collect data from the satellite and its status remains uncertain. Most likely it is offline forever. So our ability to find huge numbers of exoplanets via space observatory has temporarily been halted.
Kepler was launched in 2009 for a four year mission, however the mission was recently extended until 2016 (since it took longer to collect and make sense of the data then initially planned). At last count Kepler had discovered 132 planets and was monitoring more than 2,700 further candidate planet. As of November 2011, COROT had found 24 new worlds and was screening around 600 additional candidates for confirmation. Additionally two years of Kepler data has been downloaded but not yet interpreted so post-mortem discoveries may lie ahead.
It is frustrating that the age of almost daily discovery of new worlds has come to a temporary end due to equipment failure, however a new generation of planet finding missions is already on the drawing board. To quote The Guardian:
The European Space Agency announced last year that it would launch the Characterising Exoplanets Satellite (Cheops) in 2017 to study bright stars with known planets orbiting them. Nasa’s successor to Kepler will be the Transiting Exoplanet Survey Satellite (Tess), which will conduct a survey of planets around more than two million stars over the course of two years.
RIP Kepler and COROT, you discovered so many planets and you will be missed, but your successors will be even greater.
Gamma rays have the most energy of any wave in the electromagnetic spectrum (which includes more familiar radiation such as x-rays, radio, and visible light). The wavelength of gamma rays (10 picometers and smaller–which is a subatomic scale) is less than that of any other sort of EM radiation. Such radiation is created in the event horizons of massive black holes and during the destruction of gigantically massive stars. Comic book enthusiasts know gamma rays as the mysterious super force which created and empowers the incredible hulk, although actual cell biologists recognize gamma rays as ionizing radiation–supremely hazardous to living entities.
On Saturday, April 27, the Fermi Gamma-Ray Telescope (a NASA satellite which orbits around Earth) detected a sudden brilliant surge of gamma radiation from the collapse of a super massive star in a galaxy 3.6 billion light-years away. Gamma ray burst travel in vastly powerful beams which are very narrow–an effect which is a result of the shape of supernovae, as illustrated in the picture above. Our old friend Eta Carinae has probably exploded and produced such a burst by now. A gamma ray bust from a nearby Wolf–Rayet would probably fry away life on our planet if it were aimed directly at Earth, but such explosions are increasingly rare as the universe ages. Scientists can monitor gamma bursts from the edge of the universe (i.e. the distant past) but such a powerful event has never been monitored by our modern satellites and observatories from a middle range until now.
As the gamma ray burst fades (and the astronomy community begins to assess the initial data) other observatories will be on the lookout for the next wave of phenomena associated with the supernova. Most of the energy of a supernova explosion is believed to be dissipated as neutrinos (esoteric subatomic particles which react very little with physical matter in this universe). Fortunately humankind now possesses a sophisticated neutrino observatory on the South Pole where thousands of sensors are imbedded within a vast amount of Antarctic ice. In the rare cases where neutrinos interact with matter, they produce a cascade of charged particles which can emit Cherenkov radiation (familiar as the spooky blue glow in a nuclear reactor). Understanding the neutrino signature of such an event would potentially further our understanding of the physical parameters of existence.
Also, a luminous flash of less energetic radiation (x-rays, radio waves, light, and so forth) should be following the gamma ray burst. We understand these parts of supernovae better (since they are visible from many angles unlike the linear gamma ray bursts), but it should still be pretty–and round out our understanding of the full astronomical event.
Living during the communications revolution, it sometimes seems impossible to imagine how quickly the world has changed. Today is the 50th anniversary of an important step towards the instantly connected world of today: on July 10, 1962, a Thor-Delta rocket (launched from Cape Canaveral) carried the communication satellite Telstar 1 into orbit. The satellite was built by collaboration between AT&T, Bell Labs, NASA, the British General Post Office, and the French National Post, Telegraph, and Telecom Office. It was the first satellite ever to relay television, telephone and high-speed data communications. It was the first time that humans could beam such complicated information across an entire ocean via electromagnetic transmission.
Telstar was tiny and crude by today’s standards. The entire spacecraft weighed only 77 kg (170 lbs). The power generated by its solar panels was a mighty 14 watts (which is about what is necessary to operate a dim fluorescent nightlight). Since Telstar 1 was in non-geosynchronous orbit, its ability to transmit transatlantic signals was limited to a 20 minutes window during each 2.5 hour world orbit (and because satellite broadcasting stations only existed in England, France, and on the East Coast, the rest of the world didn’t matter) . Most contemporary telecommunications satellites are in geosynchronous orbit (and stay in place despite the solar wind thanks to thruster burns), but Telstar came in an era before all of that. The satellite’s first broadcast (on July 23rd) consisted of President John F. Kennedy talking about the dollar’s rapidly appreciating value. The initial broadcast also showed a baseball game, the American flag, Mount Rushmore, and, of course French singer Yves Montand.
Telstar 1 had a brief and memorable life broadcasting one grainy channel of black and white television and relaying perhaps a few hundred phone lines, but it has not been broadcasting since 1963. High altitude nuclear tests carried out during 1962 supercharged the Van Allen belt and overwhelmed the fragile electronics on the craft. As of May 2012 Telstar was still in orbit around Earth—presumably it is still up there, circling our planet, simultaneously a communications milestone and a cold war victim.
Cerise is a vibrant pinkish shade of red. The color is uniquely lovely–particularly as a glowing light against a dark backdrop, and the name has a long history (having been used to describe that particular shade of red since the middle of the 19th century). Unfortunately there isn’t as much to write about cerise as about some other colors.
Cerise means cherry in French and I thought it would be appropriate to write about the color as cherry-picking season arrives. When I was a teenager, my parents dragged me to an orchard to pick cherries around the end of June every year. I was always aggrieved to be rousted from bed first thing on a Saturday morning and I treated the annual event as an ordeal–but now I miss cherry picking and I particularly miss having cherries. The very beautiful ornamental cherry tree in the back yard of where I live is an ornamental cherry which produces no fruit. Aside from a few tiny plastic containers of pricey bing cherries, I have to be content with the color.
The name “Cerise” has one other claim to fame. In 1995, the French military launched a spy satellite of that name from Centre Spatial Guyanais (the ESA spaceport in French Guiana which now includes the infamous former penal colony of Devil’s Island) in order to monitor high frequency radio transmissions. One year later, Cerise was struck by a fragment of an Ariane rocket. To quote NASA, “The debris appeared to have impacted the stabilization boom, which extended 6 m from the main body of the spacecraft, at over 14 km/s (31,000 miles/hour).” It was the first recorded space collision of a space craft with space junk (although not the last). Incredibly, the satellite remained operational however the boom broke off and joined the tens of thousands of other bits of space debris–lethal low hanging fruit whipping through near-Earth orbit.
When the Japanese space program successfully launched the solar sail IKAROS last year, Ferrebeekeeper noted that NASA had its own solar sail missions planned. Last Friday, January 21st 2011, the United States Space Agency successfully deployed a 100-square-foot polymer sail in low-Earth orbit. To quote the Satellite Spotlight website, the tiny craft, unromantically named “NanoSail-D2” was, “designed to demonstration the deployment of a compact solar sail boom system for use in deorbiting satellites and as an alternate means of propulsion to move satellites in space that doesn’t require fuel.”
Although NASA’s Nano press page does not dwell on the mission’s problems, it has hardly gone off as planned. As the name indicates, NanoSail-D2 is a tiny satellite. Furled up in preparation for launch it was only 30 cm x 10 cm x 10 cm—about the size of a men’s size 12 shoe or a medium sour-dough loaf. The satellite was supposed to be launched from its mother satellite, FASTSAT–a multi-experiment platform about the size of a dishwasher–on December 6th, but nothing happened. Even though the launch door opened, the little sail remained folded up it in its launcher. The solar sail mission was deemed a failure and NASA concentrated on the FASTSAT’s five other microsatellite experiments. Then, unexpectedly the solar sail spontaneously launched on January 19th. It finished unfurling on the 21st and amateur ham radio enthusiasts tracked the craft’s beacon signals until its batteries wore out. You can find the satellite’s orbital path at the following link. It should be quite visible traveling across the sky at night for another 70-120 days after which the drag of the sail will cause it to deorbit and burn up in the atmosphere.
NanoSail-D2 was the successor to the unsuccessful NanoSail-D which fell into the Pacific Ocean (along with an Air Force satellite, a pharmaceutical satellite meant to study yeast in zero gravity, and a canister of cremated human remains) on August 3rd, 2008 when the Falcon I rocket carrying these respective payloads veered off-course. The FASTSAT (along with the NanoSail-D2 and sundry other payloads) were launched from Kodiak on a Minotaur IV—a Peacekeeper ICBM modified for commercial and research purposes.
Although I applaud NASA’s ingenuity and celebrate the successful launch of an American solar sail, I note that on December 8th, as NanoSail D2 sat malfunctioning in its launch bay, the Japanese IKAROS sail completed its primary mission when it flew by Venus at a distance of about 80,800 km (50,000 miles). Japan is now planning a series of larger and more spectacular solar sail missions which they hope will culminate with a mission to Jupiter.