A false-color image, taken by the Cassini spacecraft, of a huge hurricane at Saturn's north pole. Credit: NASA/JPL-Caltech/SSI
With the premiere of the revamped “Cosmos” series, NASA used this opportunity to showcase the imagery and missions that are such a big part of our explorations of the Universe, live-Tweeting during the show:
The Goddard Space Flight Center Flickr page featured a gallery of images from the cosmos, many which are part of the “Cosmos” series. See a sampling of great images below:
This mosaic of M31 merges 330 individual images taken by the Ultraviolet/Optical Telescope aboard NASA’s Swift spacecraft. It is the highest-resolution image of the galaxy ever recorded in the ultraviolet. The image shows a region 200,000 light-years wide and 100,000 light-years high (100 arcminutes by 50 arcminutes). Credit: NASA/Swift/Stefan Immler (GSFC) and Erin Grand (UMCP)NASA’s IMAGE Spacecraft View of Aurora Australis from Space. Credit: NASA.On August 31, 2012 a long filament of solar material that had been hovering in the sun’s atmosphere, the corona, erupted out into space at 4:36 p.m. EDT. The coronal mass ejection, or CME, traveled at over 900 miles per second. The CME did not travel directly toward Earth, but did connect with Earth’s magnetic environment, or magnetosphere, causing aurora to appear on the night of Monday, September 3. The image above includes an image of Earth to show the size of the CME compared to the size of Earth. Credit: NASA/GSFC/SDOThis planetary nebula’s simple, graceful appearance is thought to be due to perspective: our view from Earth looking straight into what is actually a barrel-shaped cloud of gas shrugged off by a dying central star. Hot blue gas near the energizing central star gives way to progressively cooler green and yellow gas at greater distances with the coolest red gas along the outer boundary. Credit: NASA/Hubble Heritage TeamThis Hubble photo is of a small portion of one of the largest seen star-birth regions in the galaxy, the Carina Nebula. Towers of cool hydrogen laced with dust rise from the wall of the nebula. Credit: NASA, ESA, and M. Livio and the Hubble 20th Anniversary Team (STScI).
There’s a lot you can learn by just staring at an object, watching how it changes in brightness. This is the technique of photometry, and it has helped astronomers discover variable stars, extrasolar planets, minor planets, supernovae, and much more. Continue reading “Astronomy Cast Ep. 337: Photometry”
Dr. Neil deGrasse Tyson contemplates the Big Bang. Image courtesy of Fox.
With much anticipation from the astronomy and science community, the opening episode of the new and updated version of Carl Sagan’s “Cosmos” series premiered to the masses on television in North America last night. This reboot – this time hosted by astrophysicist Neil de Grasse Tyson — did a wonderful job of paying homage to Sagan while showcasing the grandeur of space, as well as portraying the infinitesimally small amount of time that humanity has existed. Like its original counterpart, the first episode of the series takes viewers on a quick tour of the Solar System and Universe, showing our cosmic “address” as it were, going back to the Big Bang, but also touching on multiverses and a potentially infinite Universe.
As de Grasse Tyson said at the beginning, “from the infinitesimal to the infinite; from the dawn of time to the distant future.”
There were also – seemingly – an infinite number of commercial interruptions. You can watch the episode in its entirety below, without commercials, thankfully. Watching it on television last night was disappointing because of those commercial interruptions – sometimes only a couple of minutes apart — making one wish for the PBS-commercial-free version of the original Cosmos with Sagan.
And I wasn’t the only one feeling those sentiments:
What I miss most from the original 'Cosmos'? No commercials #Cosmos
(Yes, I watched the show while keeping an eye on what the Twitterverse had to say about it.)
But airing the series on the Fox Network and its affiliated channels (I watched it on the National Geographic Channel) was a calculated move by the series’ producer Seth MacFarlane to showcase the series and the science to a population that may not otherwise be exposed to science at this “popular” level. And clearly, science and the scientific method gets top billing in this series:
“This adventure is made possible by generations of searchers strictly adhering to a general set of rules: test ideas by experiment and observation … follow the evidence where it leads and question everything,” said Tyson.
This planetary nebula’s simple, graceful appearance is thought to be due to perspective: our view from Earth looking straight into what is actually a barrel-shaped cloud of gas shrugged off by a dying central star. Hot blue gas near the energizing central star gives way to progressively cooler green and yellow gas at greater distances with the coolest red gas along the outer boundary. Credit: NASA/Hubble Heritage Team
With a combination of real images from telescopes and spacecraft, computer generated imagery and surprisingly watchable animations, most intriguing for me was the “cosmic calendar.” Those who have seen Sagan’s original series will remember his version of the cosmic calendar as a way to conceptualize the age of the Universe, compressing 13.9 billion years down to one year. Tyson’s flashier calendar also showed how January 1 would mark the Big Bang and December 31 would be the present – making each day represent about 40 million years. At this rate, humanity’s entire recorded history only occupies just the last 14 seconds of the year.
But as Tyson noted, science has provided unmatched discoveries during that short span of time: “The scientific method is so powerful that in a mere four centuries, it has taken us from Galileo’s’ first look through the telescope to knowing our place in the Universe.”
Giordano Bruno in Cosmos. Image courtesy of Fox.
When I heard there were going to be animated sequences of historical events (the original series used actor portrayals) I was disappointed, but the animations in this series premiere surprised me by being quite engaging.
They told the story of Giordano Bruno, the 16th century Italian monk turned astronomer. He had theorized that other planets existed with other lifeforms like ours. In his 1584 book “On the Infinite Universe and Worlds,” Bruno wrote : “… there is a single general space, a single vast immensity which we may freely call Void; in it are innumerable globes like this one on which we live and grow. This space we declare to be infinite… In it are an infinity of worlds of the same kind as our own.”
This was controversial for his time, but even in a church-dominated society, it wasn’t grounds for being declared a heretic. But later Bruno followed his argument to its logical conclusion: if there are an infinity of worlds, and if some worlds have sentient beings created by God, then wouldn’t these planets also need to be saved by God? The notion other Jesuses was not viewed well, and the church convicted him of heresy, and burned him at the stake.
Phil Plait talked more about this today in his review of “Cosmos” and I agree with him that this wasn’t really about showing religion in a bad light, but about making “a bigger point about suppression of thought and the grandeur of freedom of exploration of ideas.”
Other fun moments were when a CGI (but quite realistic) dinosaur fish named a Tiktaalik crawled out of the sea right next to Tyson, depicting the evolution of life on Earth. Most endearing was perhaps Tyson’s claim that “we are ALL descended from astronomers;” how our ancestors depended on the stars to know the change of seasons.
While this series premier was a quick overview, one surprise is that it showed just one theory – and the oldest and perhaps outdated — of how our Moon was formed, by a conglomeration of the same debris that make up Earth. These days it seems the theory of a Mars-sized planetary collision is the most accepted theory.
The show began and ended with the voice and words of Carl Sagan, and Tyson shared his story about his own personal interactions with Sagan. This was a very authentic part of the show, and allowed the torch to be passed from Sagan to Tyson.
If you missed it: Karma. "For Neil Tyson, With all good wishes to a future astronomer" – Carl Sagan pic.twitter.com/BQ2p6RRRys
And then there was Tyson using Sagan’s famous “we are made star stuff” quote:
“They get so hot that the nuclei of the atoms fuse together deep within them to make the oxygen with breathe, the carbon in our muscles, the calcium in our bones, the iron in our blood,” Tyson said. “You, me, everyone: We are made of star stuff.”
Astronomer thought process: RT @Alex_Parker: S?T?A?R? ?G?U?T?S?
S?T?A?R? ?R?E?F?U?S?E?
S?T?A?R? ?B?E?L?L?Y?B?U?T?T?O?N? ?L?I?N?T?
STAR STUFF
This series premiere was a rousing tribute to science and I am definitely looking forward to more. Here’s hoping this series does what MacFarlane had in mind: get the general public to start talking about science again.
If you are feeling the need for more “Cosmos” you can watch the original series at Hulu Plus, and at the Carl Sagan website, learn more about the legend.
Live in the New York City tri-state area, or anywhere near the path above? One of the most unusual big ticket astronomical events of 2014 occurs on in the morning hours of Thursday March 20th, when the asteriod 163 Erigone “blocks” or occults the bright star Regulus.
Occultations of stars by asteroids are often elusive events, involving faint stars and often occurring over remote locales. Not so with this one. In fact, the occultation of Regulus on March 20th will result in an “asteroid shadow” passing over viewers across the populous areas of New York and adjoining states in the U.S. northeast before racing into Canada.
And unlike most asteroid occultations, you won’t need any special equipment to detect this event. Shining at magnitude +1.3, Regulus is an easy and familiar naked eye object and is the 22nd brightest star in the sky. And heck, it might be interesting just to catch a view of the constellation Leo minus its brightest star!
Finding Regulus: Looking westward from the New York tri-state region at the time of the occultation. Credit: Stellarium.
Asteroid 163 Erigone shines at magnitude+12.4 during the event. At 72 kilometres in diameter and 1.183 A.U.s distant during the occultation, 163 Erigone was discovered by French astronomer Henri Joseph Perrotin on April 26th, 1876.
There’s a great potential to learn more not only about 163 Erigone during the event, but Regulus itself. Amateur observations will play a key role in this effort. The International Occultation Timing Association (IOTA) seeks observations from this and hundreds of events that occur each year. Not only can such a precise measurement help to pin down an asteroid’s orbit, but precise timing of the occultation can also paint a “picture” of the profile of the asteroid itself.
An example of an asteroid shape profile created by observers during the occultation of a star by asteroid 55 Pandora in 2007. Each cord represents an observer. Credit- The IOTA.
Regulus also has a faint white dwarf companion, and it’s just possible that it may be spied a fraction of a second before or after the event. Does 163 Erigone have a moon? Several asteroids are now known to possess moons of their own, and it’s just possible that 163 Erigone could have a tiny unseen companion, the presence of which would be revealed by a small secondary event. Observers along and outside the track from Nova Scotia down to Kentucky are urged to be vigilant for just such a surprise occurrence:
A widened map of the March 20th event, noting the span over which an unseen “moon” of 163 Erigone could be potentially observed. Credit: IOTA/Ted Blank/Google Earth.
The maximum duration for the event along the centerline is 14.3 seconds, and the rank for the event stands at 99%, meaning the path is pretty certain.
The shadow touches down on Earth in the mid-Atlantic at 5:53 Universal Time (UT), and grazes the island of Bermuda before making landfall over Long Island New York, New Jersey, Connecticut and northeastern Pennsylvania just after 6:06 UT/2:06 AM EDT. From there, the shadow of the asteroid heads to the northwest and crosses Lake Ontario into Canada before passing between the cities of Ottawa and Toronto just before 6:08 UT. Finally, it crosses out over Hudson Bay and Nunavut before departing the surface of our fair planet at 6:22 UT.
The path is about 117 kilometres wide, and the “shadow” races across the surface of the Earth at about 2.8 kilometres per second from the southeast to the northwest.
A technical map including the specifics for the March 20th occultation of Regulus. Click to enlarge. Credit: The IOTA.
Timing an occultation can be accomplished via audio or video recording, though accurate time is crucial for a meaningful scientific observation. The IOTA has a complete explanation of tried and true methods to use for capturing and reporting the event.
We had a chance to catch up with veteran asteroid occultation observer Ted Blank concerning the event and the large unprecedented effort underway to capture it.
He notes that Regulus stands as the brightest star that has been observed to have been occulted by an asteroid thus far when 166 Rhodope passed briefly in front of it on October 19th, 2005.
“This is the best and brightest occultation ever predicted to occur over a populated area, and that covers the entire 40 years of predictive efforts,” Mr. Blank told Universe Today concerning the upcoming March 20th event.
The general public can participate in the scientific effort for observations as well.
“We’re trying to make a “picket fence” of thousands of observers to catch this asteroid, so the best thing to do is to go out and observe. If they live anywhere near or in the path, just step outside (or watch from a warm house through a window). Make sure they are looking at the right star,” Mr. Blank told Universe Today. “If they can travel an hour or so to be somewhere in the predicted path, by all means do so – they’ll be home and back in bed well before rush hour starts! Then report what they saw at the public reporting page. If no occultation was seen, report a miss. This is more important that people think, since “miss” observations define the edges of the asteroid.”
There is also a handy “Occultation 1.0” timing app now available for IPhone users for use during the event.
Mr. Blank also plans to webcast the occultation live via UStream, and urges people to check the Regulus2014 Facebook page for updates on the broadcast status, as well as the final regional weather prospects leading up event next week. For dedicated occultation chasers, mobility and the ability to change observing locale at the last moment if necessary may prove key to nabbing this one. One of our preferred sites to check the cloud cover forecast prior to observing any event is the Clear Sky Chart.
This promises to be a historic astronomical event. Thanks to Ted Blank and Brad Timerson at the IOTA for putting the public outreach project together for this one, and be sure not to miss the occultation of Regulus on March 20th!
Trying to keep a low profile, to prevent the aliens from invading? Bad news. Life has actually been broadcasting our existence to the Universe for hundreds of millions of years.
Have you heard these crazy plans to send signals out into deep space? What if evil aliens receive them, come steal our water, enslave, eat, and use us as guinea pigs for their exotic probulators. How we could stop these madmen from announcing our presence to the galaxy? A petition on whitehouse.gov? An all caps Facebook group? An all pusheen protest? Somebody call Reddit, they’ll know what to do.
If this is a worry for you and your friends, I’ve got bad news, or possibly good news depending on which side you come down on. We’ve already been broadcasting our existence for hundreds of millions of years. If aliens wanted to know we were here, all they needed to do was look through their telescopes.
We’re in a golden age of extrasolar planet discovery, recently crossing the thousand-planets-mark thanks to Kepler and other space telescopes. With all these amazing planetary candidates, our next challenge will be to study the atmospheres of these planets, searching for evidence of life. There are chemicals which are naturally occurring, like water and carbon dioxide, and there are substances that can only be present if some source is replenishing them. Methane, for example, would only last only few hundred years in the atmosphere if it wasn’t for farting cows and colonies of bacteria eating dead things.
If we see methane or oxygen in the atmosphere of an extrasolar planet, we’ll have a good idea there’s life there. And if we see the byproducts of an industrial civilization, like air pollution, we can pinpoint exactly where they are in their technical development. It will work for us, and that means it would work for aliens.
For the first few billion years, oxygen was toxic. But then cyanobacteria evolved photosynthesis and figured out how to work with oxygen more than 2.4 billion years ago. This is known as the Great Oxidation Event.
For the first billion years, all this biologically generated oxygen was absorbed by the oceans and the rocks. Once those oxygen sinks filled up, oxygen began accumulating in the atmosphere. By 500 million years ago, there was enough oxygen in the atmosphere to support the kind of breathing we do today. And this much oxygen would have been obvious to the aliens. They would have known that life had evolved here on Earth, and they could have sent out their berserker spaceships to steal our water and made us watch while they ate all our small rodents.
If the aliens waited, we would have given them more signs. The Industrial Revolution began in the mid 1700’s. And this time, it was humans that filled the atmosphere with the pollution of our industrial processes. Again, aliens watching the planet with their space telescopes would know the moment we became a technological civilization.
The innermost antennae along the north arm of the Very Large Array, superimposed upon a false-color representation of a radio (red) and optical (blue) image of the radio galaxy 3C31. Image courtesy of NRAO/AUI
In the 20th century, we harnessed the power of radio transmissions, and began sending our messages out into space. For about a hundred years now, our transmissions have been expanding into a bubble of space. And so, any aliens listening within this expanding sphere of space might have a chance of hearing us. They know we’re here, and they know some of us really like Ke$ha.
And finally, for the last few decades, a few groups have tried broadcasting messages using our powerful radio telescopes directly at other stars. These messages haven’t gotten very far, but I honestly wouldn’t worry. Life itself gave away our position hundreds of millions of years ago. And life will help us find other civilizations, if they’re out there.
What do you think? Should we turn out the lights and pretend like we’re not home or keep on actively broadcasting our presence to the Universe? Tell us what you think we should do in the comments below.
Hypothetical astronaut mission to an asteroid. Credit: NASA Human Exploration Framework Team
Fancy yourself an asteroid hunter? There’s $35,000 available in prizes for NASA’s new Asteroid Data Hunter contest series, which will be awarded to citizen scientists who develop algorithms that could be used to search for asteroids.
Here’s where you can apply for the contest, which opens March 17 and runs through August. And we have a few more details about this joint venture with Planetary Resources Inc. below.
“The Asteroid Data Hunter contest series challenges participants to develop significantly improved algorithms to identify asteroids in images captured by ground-based telescopes,” NASA stated. “The winning solution must increase the detection sensitivity, minimize the number of false positives, ignore imperfections in the data, and run effectively on all computer systems.”
In November, NASA announced that Planetary Resources (the company best known for the “selfie” space telescope) is going to work on “crowdsourced software solutions” with NASA-funded data to make it easier to find asteroids and other near-Earth objects.
Artist's impression (not to scale) of the Rosetta orbiter deploying the Philae lander to comet 67P/Churyumov–Gerasimenko. Credit: ESA–C. Carreau/ATG medialab.
After four months behind the sun from Earth’s perspective, comet 67P/Churyumov-Gerasimenko is back in view — and brighter than ever! New pictures of the comet reveal it is 50 percent brighter than the last images available from October 2013. You can see the result below the jump.
“The new image suggests that 67P is beginning to emit gas and dust at a relatively large distance from the Sun,” stated Colin Snodgrass, a post-doctoral researcher at the Max Planck Institute for Solar System Research in Germany. Snodgrass added that this confirms previous work he and his colleagues did showing that in March 2014, the comet’s activity could be seen from Earth.
Pictures were taken with the European Southern Observatory’s Very Large Telescope from 740 million kilometers (460 million miles) away. As you can see in the image below, several exposures were taken to obtain the fainter comet. And we know that scientists are eager to take a closer look with Rosetta.
Comet 67P/Churyumov-Gerasimenko on images obtained Feb. 28th, 2014 with the Very Large Telescope. Left: Several exposures were obtained of the faint comet, and superimposed upon each other, making stars appear as streaks. Right: The comet in an image processed to remove the stars. Credit: MPS/ESO
In January, the Rosetta spacecraft woke up after 31 months of hibernation (a little later than expected, but still healthy as ever.) It’s en route to meet up with the comet in August and will stay alongside it at least until 2015’s end. The next major step is to wake up its lander, Philae, which will happen later this month.
Should all go to plan, Philae will make a daring landing on the comet in November to get an up-close view of the activity as the comet flies close to the sun. You can read more details in this past Universe Today story.
A SpaceX Falcon 9 rocket with Dragon cargo capsule bound for the ISS launched from Space Launch Complex 40 at Cape Canaveral, FL. File photo. Credit: Ken Kremer/kenkremer.com
The historic blast off of the first SpaceX rocket equipped with ‘landing legs’ and also carrying a private Dragon cargo vessel bound for the Space Station is now slated for March 16 following a short and “successful” hot fire check test of the first stage engines on Saturday, March 8.
It’s T Minus 1 week to lift off !
The brief two second ignition of all nine upgraded Merlin 1D engines powering the first stage of SpaceX’s next generation, commercial Falcon 9 rocket at the end of a simulated countdown is a key test required to clear the way for next Sunday’s planned night time lift off at 4:41 a.m. EDT from Space Launch Complex 40 at Cape Canaveral Air Force Station in Florida.
“Falcon 9 and Dragon conducted a successful static fire test in advance of next week’s CRS-3 launch to station!” SpaceX announced today.
The primary goal of the unmanned SpaceX CRS-3 mission is to deliver over 5000 pounds of science experiments, gear and supplies loaded inside Dragon to the six person crew living and working aboard the International Space Station (ISS) flying in low Earth orbit under NASA’s Commercial Resupply Services (CRS) contract.
“In this final major preflight test, Falcon 9’s 9 first-stage engines were ignited for 2 seconds while the vehicle was held down to the pad,” said SpaceX.
All four landing legs now mounted on Falcon 9 rocket being processed inside hanger at Cape Canaveral, FL for Mar 16 launch. Credit: SpaceX/Elon Musk
The static hot firing is a full up assessment of the rocket, engines, propellant loading and countdown procedures leading to a launch. The engines typically fire for a barely a few seconds.
SpaceX engineers will evaluate the engine firing to ensure all systems are ready for launch.
This commercial Falcon 9 rocket is equipped for the first time with a quartet of landing legs, Elon Musk, the company’s founder and CEO, announced recently as outlined in my story – here.
The attachment of landing legs to the first stage of SpaceX’s next-generation Falcon 9 rocket counts as a major step towards the firm’s future goal of building a fully reusable rocket.
The eventual goal is to accomplish a successful first stage touchdown by the landing legs on solid ground back at Cape Canaveral, Florida.
For this Falcon 9 flight, the rocket will sprout legs for a controlled soft landing in the Atlantic Ocean guided by SpaceX engineers.
Extensive work and testing remains to develop and refine the technology before a land landing will be attempted by the company.
“F9 will continue to land in the ocean until we prove precision control from hypersonic thru subsonic regimes,” Musk says.
1st stage of SpaceX Falcon 9 rocket equipped with landing legs and now scheduled for launch to the International Space Station on March 16, 2014 from Cape Canaveral, FL. Credit: SpaceX/Elon Musk
SpaceX hopes the incorporation of landing legs will one day lead to cheaper, reusable boosters that can be manufactured at vastly reduced cost.
The March 16 launch will be the fourth overall for the next generation Falcon 9 rocket, but the first one capped with a Dragon and heading to the massive orbital lab complex.
Falcon 9 and Dragon static fire test on March 8, 2014. Credit: SpaceX
Three prior launches of the more powerful Falcon 9 lofting commercial telecom satellites in September and December 2013 and January 2014 were all successful and paved the way for SpaceX’s new mission to the ISS.
And this Dragon is loaded with the heaviest manifest yet.
The research cargo includes 100 protein crystal experiments that will allow scientists to observe the growth of crystals in zero-G.
In the absence of gravity, the crystals will hopefully grow to much larger sizes than here on Earth and afford scientists new insights into designing and developing new drugs and pesticides.
SpaceX is under contract to NASA to deliver 20,000 kg (44,000 pounds) of cargo to the ISS during a dozen Dragon cargo spacecraft flights over the next few years at a cost of about $1.6 Billion.
Next Generation SpaceX Falcon 9 rocket blasts off with SES-8 communications satellite on Dec. 3, 2013 from Pad 40 at Cape Canaveral, FL. Credit: Ken Kremer/kenkremer.com
To date SpaceX has completed two operational cargo resupply missions. The last flight dubbed CRS-2 blasted off a year ago on March 1, 2013 atop the initial version of the Falcon 9 rocket.
If the launch takes place as planned on March 16, Dragon will rendezvous and dock at the Earth facing port on the station’s Harmony module, after a two day orbital chase, on March 18.
Both the Dragon and Cygnus resupply spacecraft were privately developed with seed money from NASA in a public-private partnership in order to restore the cargo up mass capability the US completely lost following the retirement of NASA’s space shuttle orbiters in 2011.
The Dragon docking will take place a few days after Monday’s (March 10) scheduled departure of three crew members aboard a Russian Soyuz capsule.
Watch the Soyuz leave live on NASA TV.
The departure of Russian cosmonauts Oleg Kotov and Sergey Ryazanskiy along with NASA astronauts Mike Hopkins marks the end of Expedition 38 and the beginning of Expedition 39.
It also leaves only a three person crew on board to greet the Dragon.
The Soyuz return to Earth comes amidst the ongoing Crimean crisis as tensions continue to flare between Russian, Ukraine and the West.
Expedition 38 crew members proudly sport their national flags in this March 2014 picture from the International Space Station. Pictured (clockwise from top center) are Russian cosmonaut Oleg Kotov, commander; Japan Aerospace Exploration Agency astronaut Koichi Wakata, Russian cosmonaut Sergey Ryazanskiy, NASA astronauts Rick Mastracchio and Mike Hopkins, and Russian cosmonaut Mikhail Tyurin, all flight engineers. Credit: NASA
Command of the station was passed today from Oleg Kotov to the Japan Aerospace Exploration Agency astronaut Koichi Wakata.
With the start of Expedition 39, Wakata thus becomes the first Japanese astronaut to command the ISS.
Wakata and NASA astronaut Rick Mastracchio with use the stations Canadarm 2 to grapple and berth Dragon to its docking port.
Dragon is due to stay at station for about three weeks until April 17.
Then it will undock and set course for a parachute assisted splash down in the Pacific Ocean off the coast of Baja California.
For the return to Earth, Dragon will be packed with more than 3,500 pounds of highly valuable experiment samples accumulated from the crews onboard research as well as assorted equipment and no longer need items.
Stay tuned here for Ken’s continuing SpaceX, Orbital Sciences, commercial space, Orion, Chang’e-3, LADEE, Mars rover, MAVEN, MOM and more planetary and human spaceflight news. Learn more at Ken’s upcoming presentations at the NEAF astro/space convention on April 12/13.
And watch for Ken’s upcoming SpaceX launch coverage at Cape Canaveral & the Kennedy Space Center press site.
Lambda Geminorum at 10:43 p.m. March 11 just two minutes before disappearing behind the moon as seen from Minneapolis, Minn. US. Stellarium
Ever dabbled in the occult? You’ll have your chance Monday night March 10 when the waxing gibbous moon glides in front of the star Lambda Geminorum for much of North America, occulting it from view for an hour or more. Occultations of stars by the moon happens regularly but most go unnoticed by casual skywatchers. Lambda is an exception because it’s one of the brighter stars that happens to lie along the moon’s path. Shining at magnitude +3.6, any small telescope and even a pair of 10×50 or larger binoculars will show it disappear along the dark edge of the moon.
Map showing where the disappearance (right half of tube-like figure) and reappearance of Lambda Gem will be visible. Credit: International Occultation Timing Assn. (IOTA)
With a telescope you can comfortably watch the star creep up to the moon’s edge and better anticipate the moment of its disappearance. The fun starts a few minutes before the impending black out when the moon, speeding along its orbit at some 2,280 mph (3,700 km/hr), draws very close to the star. During the final minute, Lambda may seem to hover forever at the moon’s invisible dark limb, and then – PFFFT – it’s gone! Whether you’re looking through telescope or binoculars, the star will blink out with surprising suddenness because the moon lacks an atmosphere.
Disappearance and reappearance seen from Minneapolis, Minn. Monday night. I’ve lightened the moon so you can see the dark limb. You’ll likely not see this edge in a telescope because of glare. Stellarium
If there was air up there, Lambda would gradually dim and disappear. Even without special instruments, early astronomers could be certain the moon had little if anything to protect it from the vacuum of space by observing occultations.
As the moon moves approximately its own diameter in an hour, you can watch Lambda re-emerge along the bright limb roughly an hour later, though its return will lack the drama and contrast of a dark limb disappearance. While occultations allow us to see how swiftly the moon moves in real time as well as provide information on its atmosphere or lack thereof, real science can be done, too.
Planets also are occasionally occulted by the moon. Time lapse of Venus’ disappearance on May 16, 2010
Observers along the occultation boundary in the southern U.S. can watch the star pop in and out of view as it’s alternately covered and uncovered by lunar peaks jutting from the moon’s limb. Before spacecraft thoroughly mapped the moon, careful timings made during these “grazing occultations” helped astronomers refine the profile of the moon’s limb as well as determine elevations of peaks and crater walls in polar regions. They can still be useful for refining a star’s position and motion in the sky.
The moon’s limb can also be used much like a doctor’s scalpel to split unsuspected double stars that otherwise can’t be resolved by direct observations. Take Lambda Gem for instance. We’ve known for a long time that it totes around a magnitude +10.7 companion star 10 arc seconds to its north-northeast, but previous occultations of the star have revealed an additional companion only a few hundredths of an arc second away orbiting the bright Lambda primary. The star plays a game of hide-and-seek, visible during some occultations but not others. Estimated by some as one magnitude fainter than Lambda, keep an eye out for it Monday night in the instant after Lambda goes into hiding.
Lunar occultation and reappearance of Antares Oct. 21, 2009
I watched just such a “two-step” disappearance of Antares and it fainter companion some years back. With brilliant Antares briefly out of view behind the moon’s limb, I easily spotted its magnitude +5.4 companion just 2.5 arc seconds away – an otherwise very difficult feat at my northern latitude.
Want to know more about things that disappear (and reappear) in the night? Make a visit to the International Occultation Timing Association’s websitewhere you’ll find lists of upcoming events, software and how to contribute your observations. If you’re game for Monday night’s occultation, click HEREfor a list of cities and times. Remember that the time show is Universal or Greenwich Time. Subtract 4 hours for Eastern Daylight, 5 for Central, 6 for Mountain and 7 for Pacific. Wishing you clear skies as always!
