[/caption]It is probably the most seductive urge for mankind: search for extraterrestrial life. There are many ways to look for life; from digging into the Martian dirt with robotic landers looking for pre-biotic compounds, to building vast radio antennae to “listen” out for distant communications either leaked or transmitted deliberately from a distant star system from a developed, intelligent civilization. However, despite our best efforts, we appear to be the only form of life for hundreds of lightyears around. It is eerily quiet out there…
Although we appear to be drawing blanks so far, it doesn’t stop us from trying to work out what we should be looking for. In the quest to find a vastly advanced alien civilization, a forthcoming Russian space telescope hopes to bridge the gap between science fiction and science fact, attempting to find evidence (or lack thereof) of observable attempts of astroengineering by an alien race…
New and exciting ways are being formulated to work out whether intelligent life does exist beyond our blue oasis. Programs such as the famous Search for Extra-Terrestrial Intelligence (SETI), Messaging to Extra-Terrestrial Intelligence (METI) and the tongue-in-cheek Wait for Extra-Terrestrial Intelligence (WETI) are conceived to somehow interact with a sufficiently advanced alien culture (one that has the ability to communicate via radio, at least). In an engrossing entry I read in last week’s Carnival of Space Week 86, Dr Bruce Cordell (21st Century Waves) discussed the apparent paradox between UFOs and Fermi’s Paradox (in a nutshell: if aliens have visited our planet, as UFO sightings would lead us to believe, why haven’t we intercepted any kind of signal via SETI?). I was most interested with Cordell’s thoughts on optical communications that could be used by extraterrestrials to communicate with a pre-radio communication human era. Apparently, in 40 years, mankind could be generating very bright signals using 30 terrawatt optical beacons for pre-radio civilizations to see over 10 light years away, brighter than their brightest star. If there are advanced civilizations out there, why have we not seen their optical transmissions?
To summarize, we are a little confused by the lack of life in our Universe (intelligent life in any case).
So, perhaps we can find other ways to spy on our hypothetical alien neighbours. Could we build a powerful telescope to seek out structures built by alien civilizations? Possibly, according to a forthcoming Russian space-based telescope project: The Millimetron Space Telescope.
On reading an article about this subject on the Daily Galaxy, I thought I’d heard of something like this before. Sure enough, during my research on the Infrared Astronomical Satellite, IRAS (surrounding the whole Planet X controversy), I found out that work was being done to try to find the infrared signature of the hypothetical Dyson Sphere. The Dyson Sphere is a theorised example of an astroengineered structure by a significantly advanced alien race. There are many variations on this theme, including science fiction ideas of an engineered “ring” straddling a host star (as pictured top). In the case of the Dyson Sphere, this megastructure would generate infrared radiation, and analysis of IRAS data has been done to establish an upper limit on the existence of these objects. So far, no Dyson Sphere candidates have been found (within 300 light-years from Earth in any case).
To build on the IRAS survey, in 2017, Russia hopes to launch the Millimetron to observe distant stellar systems in millimeter, sub-millimeter and infrared wavelengths. This instrument has a long list of aims, but one of the extreme results that could come from this project is the detection of astroengineered megastructures.
The goal of the project is to construct space observatory operating in millimeter, sub-millimeter and infrared wavelength ranges using 12-m cryogenic telescope in a single-dish mode and as an interferometer with the space-ground and space-space baselines (the later after the launch of the second identical space telescope). The observatory will provide possibility to conduct astronomical observations with super high sensitivity (down to nanoJansky level) in a single dish mode, and observations with super high angular resolution in an interferometric mode. – The Millimetron Project.
By combining the orbiting telescope with observatories on the ground, it may be possible to create a very long baseline interferometer (VLBI) with huge baselines beyond 300,000km. This will provide unprecedented angular resolution. Alone, the large 12 metre dish will allow astronomers to probe emissions at the nano-Jansky level, where radio astronomers usually operate from <1-100 Janskys (the Jansky is a non-SI measurement of electromagnetic flux density).* With a system like this, very weakly radiating sources may be detected, possibly revealing structures such as the Dyson Sphere, or possibly sci-fi concepts like Larry Niven’s “Ringworld”.
Although I am dubious as to whether our persistent efforts to find intelligent extraterrestrial life will ever turn up positive, the search is exciting and certainly boosts the scientific process in directions we wouldn’t have necessarily examined…
Nili Fossae on Mars where methane has been detected. Credit: NASA/JPL/University of Arizona
At NASA’s press conference last week about methane on Mars, NASA’s lead scientist for the Mars Program Michael Meyers said straight out, “These findings are not evidence for life, but evidence for active processes on Mars.” But seemingly, not everyone in the media took the high road in reporting about the methane news, with some claiming NASA had found life on Mars.
If you missed the news conference, or didn’t read the Universe Today article on the methane news, or would like further information straight from the scientists who have been working on the methane detection on Mars for several years, NASA has put together some videos, where you can get the news straight from the scientists. The first one is with Dr. Michael Mumma of NASA’s Goddard Space Flight Center. Take a look:
And there’s more:
If you click on the little video screens on the bottom after the first video is over, you can watch a series of videos from the press conference where the methane plumes news was discussed. Sometimes its best to hear it from the scientists first-hand.
If you want to read some of the more “titillating” versions of the methane news, Phil Plait has written an article about the Mars Methane Media Mess created by some over-zealous journalists (that includes a nice compliment on our article — thanks Phil!) and Dave Mosher at Discovery Space has a post about the Mars Methane Bomb on Earth.
The Milky Way from Earth. Image Credit: Kerry-Ann Lecky Hepburn (Weather and Sky Photography)
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If you look up into the night sky on a very clear night, in an area with very little light pollution, you will see a band of stars splashed across the sky. That band is the Milky Way, the spiral galaxy in which our Solar System lies, and where almost every object you can see with your naked eye calls home.
The Solar System is inside the disk of the Milky Way, and orbits in one of the spiral arms at 26,000 light years from the center of the galaxy. We can’t see the spiral structure of the galaxy from our planet because we are inside the disk and have no means of taking images from above or below the galaxy. Images of the Milky Way’s spiral structure are created from computer modeling based on information from stars as they orbit the galaxy.
Much of the Milky Way is invisible to us because we have to look through the plane of its disk – a lot of the Milky Way is on the other side of the galaxy, and there is so much dust and so many bright stars closer to us that we can’t see the stars behind all of this matter. Of the 5,000 to 8,000 stars in the Milky Way visible to the human eye from Earth, one can usually only see about 2,500 at a time. In fact, the few thousand stars we can see of the Milky Way with our naked eye are only about 0.000003% of the 200-400 billion stars that inhabit the spiral!
To see a picture of the entire Milky Way from the surface of the Earth at once, you have to create a mosaic of photographs taken at different times. This is because the Milky Way moves overhead at night with the rotation of the Earth, so can’t be viewed all at once from one spot. Many panoramas of our galaxy can be found on the web, but here’s a few to get you started: NASA’s Astronomy Picture of the Day, the Spitzer Space Telescope’s very detailed, very large (55-meters long when printed) mosaic available for your perusal here – it’s a large image, so give it a little time to load – and a drawing by Knut Lundmark of over 7,000 stars in the Milky Way made in the 1950s.
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Jupiter is one of the 5 planets visible with the unaided eye, and so it has been known for thousands of years. But the movement of Jupiter and the other planets was a mystery until just a few hundred years ago. Jupiter moves across the sky in a very predictable pattern, but every now and then it reverses direction in the sky, making a tiny loop against the background stars – this is Jupiter retrograde.
Of course, Jupiter isn’t actually moving backwards in the sky – it orbits the Sun in the same counter-clockwise direction as the other planets. So what’s going on?
In ancient times, astronomers thought that the Sun, the Moon, the planets and the stars orbited around the Earth. This helped explain the movement of the planets, but there was a problem. The planets would occasionally reverse direction in the sky – move in a retrograde direction from the way they normally go. To explain these movements, astronomers developed a complicated model of orbiting spheres, where the planets followed a spiral path around the Earth.
This model was turned on its ear by Copernicus in the 1500s when he proposed that the planets orbited around the Sun. This also elegantly explained why Jupiter has a retrograde motion, as well as the other planets. Jupiter is following a roughly circular orbit around the Sun, but it takes 12 years to complete an orbit; while Earth takes just a year for an orbit.
The retrograde motion of Jupiter actually comes from Earth catching up to Jupiter in its orbit. As Earth passes Jupiter in orbit, we’re looking back at it as we go by. Think of a car passing another car on the highway. You see the car up ahead, and then as you pass it, the car appears to be moving backwards from your point of view. It’s not actually going backwards, of course, it’s all in your perspective.
Each Jupiter retrograde period lasts about 4 months, and happen every 9 months. Consider the orbit of the Earth and Jupiter, and you can understand that this is how long it takes Earth to complete an orbit around the Sun and then catch up with Jupiter again.
Astrologers think that Jupiter retrograde indicates some kind of change of luck and fortune, but there is nothing in the science of astronomy that supports that view at all.
Mosaic created by UMSF's James Canvin from images taken by the Opportunity rover, sol 1707. Credit: NASA/JPL/Cornell/James Canvin
[/caption] Note: This is the first in a series of articles about Citizen Science projects, where science is not just for professional scientists anymore!
The desire to seek out others of a like mind must be coded into our DNA. Take any subject — music, literature, art, science, math, sports, animals — you name it, and there is a group you can join to share your interest with others. Or if you can’t find a group, then you can start one and see who joins in. Doug Ellison is a great example. His online forum Unmannedspaceflight.com (UMSF) has become a place where a combination of interest in space exploration and serious “Photoshopping” has taken on new proportions. But it is also a place where the line between amateur interest and professional science is starting to blur.
Plainly put, the images, mosaics and movies created by the participants at UMSF are stunning. Whether it be a panoramic view from the top of Husband Hill on Mars, recalibrated images from the Pioneer or Voyager spacecraft to create 3D renderings or maps of the planets, or a movie of Opportunity roving on Meridiani Planum, the work being done at UMSF is a feast for the eyes. And this is all being done by amateurs who don’t receive any compensation for their painstaking handiwork, except for the joy of sharing their images with each other and the public, and perhaps converting a few space exploration naysayers along the way. They do their work using cheap, free, or even personally-created imaging software, to generate their labors of love.
Ellison’s interest in space exploration started with the Mars Pathfinder mission in 1997, where information and images from the mission were being shared online, just as the internet was starting to boom. But when his own country, England, led the Beagle 2 Lander mission to Mars in 2003, Ellison’s interest got a little more serious. “Being a Brit, I was proud of Beagle, and wanted to talk about it with others,” said Ellison, a media producer, “but I couldn’t find any online forums discussing the mission. So I started a Yahoo group, and about 40 or 50 people descended on it, and we posted updates about the mission.” And the online updates and discussions were serious – no talk about little green men, Martians or UFOs was allowed.
The Mars Exploration Rovers were also on Ellison’s radar, as he knew they were set to land just after Beagle 2, but he admits not paying all that much attention to the rovers. However, when all contact was lost with Beagle 2 after it separated from the Mars Express orbiter, Ellison turned his attention to the rovers. The firehose of images from the rovers was almost immediate after they landed in January 2004: Principal Investigator Steve Squyres and Pancam lead Jim Bell had both decided to post all the images online, making them available for anyone with internet access virtually the instant the data were beamed back to Earth from Mars.
“I saw all these JPEG images online at the rover site, and I couldn’t help myself!” said Ellison, who had also developed an interest in image editing. “I started making mosaics and movies from the rover images. And in the same way I couldn’t find anywhere to talk about Beagle, I couldn’t find a ‘sensible’ place to talk about the rovers, and where I could discuss the images.” UMSF image that was used on the cover of Aviation Week magazine. Credit: NASA/JPL/ Cornell and Marco Di Lorenzo, Doug Ellison, Bernhard Braun, and Kenneth Kremer
Ellison noted he hadn’t yet found the BAUT (Bad Astronomy Universe Today) forum, but he noticed that almost any website or forum where Mars was the topic, the discussion would “soon turn to anomalism, nut-jobbery, and crazy-talk, so I was determined if I couldn’t find anything I would start my own site to post my images, etc.,” he said. “And if someone came along and said something like, ‘Oh there’s a skull, and there’s cannon,’ I just wasn’t going to have it,” he said.
Ellison never advertised or “pimped” the site, and the first year things were pretty quiet, with just a few dozen people joining in who were doing their own mosaics or global maps. Then the Cassini mission came along, and those images also went straight to a publicly accessible website, so a Cassini/Saturn section was added to the forum; then a Mars orbiter section and a New Horizons section – any mission where the images were available.
“So it expanded from just being a site about the rovers to any spacecraft that was going around taking pictures,” said Ellison, “so about a year after I started the site, I re-named it unmannedspaceflight.com.”
While the site hasn’t exploded or gone completely viral, it has quietly expanded to about 1,800 active members and about 30,000 visitors a month. “It spikes when there’s something interesting happening, such as the Phoenix landing, but otherwise its fairly steady, with about 100 or so really active people contributing images, with an awful lot of people who just like to hang around and look.”
The ‘Old Days’ and Now
It used to be difficult to get images from space missions, with enthusiasts having to wait weeks or months for a print magazine or book to publish pictures taken by spacecraft. But the internet has changed all that, and in addition, attitudes among the previously exclusive science community seem to be changing as well.
“NASA really does try to make data as accessible to the public as it can,” said Emily Lakdawalla from the Planetary Society, who writes the Planetary Blog. She has been a member of UMSF since 2005, and as a planetary geologist, enjoys working with space mission images. “Anybody in the world with net access can get to all the data ever taken by nearly every NASA planetary mission,” she said. “It is sort of like discovering the back rooms of the Smithsonian collections — they display only a few percent of their artifacts. NASA captions and press-releases only a few percent of their missions’ data, but it’s all online, waiting for people to discover and use it. UMSF is a community of people who live to do just that — delve into the museum vaults, discover wonders that few people on Earth have ever seen, dust them off, restore them, and display them to public view.”
As amateurs, Lakdawalla said, they can take liberties with the data that scientists usually can’t allow themselves to. If a data dropout creates an ugly stripe across an otherwise pretty image, a scientist will usually not fudge the data to make it look better. An amateur needs to have no such constraints; they can “futz” with the images, and produce eye-catching, print-ready images out of something that would have otherwise not been very interesting to non-scientists.
“The wonderful thing about UMSF is that the community there generally takes exactly the right level of liberties with the data,” said Lakdawalla, “basically, enough fudging as is required to prevent the viewer from being distracted by artifacts of the imaging process, but little enough to let the original space data do all the talking.” A fanciful image of Opportunity's reflection in its heat sheild -- an image that was never taken, but created by Stuart Atkinson. Credit: NASA/JPL/Stuart Atkinson
While there are many space-topic forums on the internet, UMSF is different for two very important reasons, said Stuart Atkinson, care worker for the elderly in the United Kingdom by day, who has been involved with UMSF since the old days of the Beagle discussions. “Firstly, because it has a strict – and strictly enforced – policy of not tolerating ‘off topic’ posts about such things as politics, manned spaceflight, alien babies or Bigfoots on Mars and things like that,” said Atkinson. “UMSF is, as its name suggests, a forum for discussing unmanned spaceflight – spaceprobes, basically, and if anyone comes along trying to flame, or cause trouble, or claim they’ve found a piece of wood or an alien skull in a zoomed-in-to-within-an-inch-of-its-life section of a Mars rover image then they’re in the wrong place.”
The strict “policing” of the site, performed by about a dozen or so moderators has created an environment where even scientists feel comfortable joining in on the discussions. “Planetary Scientist Ralph Lorenz has come over and talked about Titan’s dunes, and Alan Stern has joined in discussions about New Horizons, for example,” said Ellison.
Which is the other thing that makes it so special, added Atkinson. “Become a member of UMSF and you’ll find yourselves rubbing virtual shoulders with many of the men and women who actually work ON the missions… Mars Rover drivers, Deep Space Network operators, Mars geologists and climatologists, they’re all members of UMSF, and clearly love being able to take part in discussions about their work.” Doug Ellison's creation of Phoenix's landing site for the Through the Eyes of the Phoenix Competition, organized by spacEurope in association with the mission's Education & Public Outreach program.
But not only have scientists joined in on discussions, they’ve come to UMSF to ask for help. Ellison said a highlight of his involvement with UMSF was when John Spencer from the New Horizons mission came to the forum asking if the members had any ideas for New Horizon’s flyby of Jupiter. “He came onto the forum and said, we’re planning the science sequence for the Jupiter flyby and do any of you have any ideas of when we should take pictures, just because they will be cool and interesting images. And he gave us the link for the tool that would show us the view from the New Horizons trajectory at a particular time, at any direction we wanted.”
Suggestions from UMSF members were put into an amalgamation of ideas from scientists and four ideas from UMSF were chosen for the flyby.
“I could not believe it, that my little forum had become an engine to come up with ideas, and these ideas got sent to a $800 million spacecraft a half a billion kilometers away,” said Ellison. “And New Horizons took this amazing picture of Europa rising up behind Jupiter. The fact that he came to us, asked us for ideas, and actually used them just was amazing.”
“New Horizons really exemplifies the best of amateurs and professionals working together,” said Lakdawalla. “All missions like to take advantage of “Kodak moments,” and the longer lived ones, particularly MER and Cassini, get the leisure to plan to take a few pictures just because they’re pretty, or significant. New Horizons wanted to do that but had a ridiculously short time between launch and Jupiter… It was a great use of amateur effort, for the right purpose — not to do science, but to do what the amateurs do best (and better than most scientists) — make pretty pictures.”
As an example of what UMSF does with images, Lakdawalla took image of Jupiter’s moons Io and Europa that was captured by New Horizons’ LORRI instrument (Long Range Reconnaissance Imager), combined it with another image taken by the MVIC (Multispectral Visible Imaging Camera) visible- and near-infrared spectrometer, to create a truly spectacular image of the pair of moons. Io and Europa together. Credit: NASA / JHUAPL / SwRI / Emily Lakdawalla
“Emily took the best data, combined them and made something better from it,” said Ellison. “I didn’t make the actual suggestion or create the actual picture but I’m very, very proud of those pictures because the people from New Horizons thought we’d come up with some sensible ideas and we did. It was an example of the amateur doing something truly spectacular.”
Ellison said starting UMSF has truly been life-changing. He has had the opportunity to meet scientists involved with the space missions, and even gave a presentation to the MER science team at Cornell University, which he said was “the highlight of my life.”
The work of another active UMSF member, James Canvin, showed up at a very special place: on the wall in the operations building for the Phoenix Mars Lander. It was visible during a visit by Sky at Night television show on BBC. “Recognition of that type, by people within the team running the mission itself is a huge honour,” said Canvin, who is a scientist for the United Kingdom’s main weather forecasting center. Canvin said image processing has become his main hobby, and countless hours have been spent writing the software to do the processing as well as producing the images themselves. James Canvin's version of Phoenix' Mission Success Panorama, which includes 150 separate camera pointings taken from sols 13 to 43. Canvin produces his mosaics using software he developed for Mars Exploration Rover panoramas. This is an interim data product, considerably reduced in resolution from the original data. Credit: NASA / JPL / UA / Texas A & M / color mosaic by James Canvin
But perhaps the biggest reward of creating these “bootleg” images is the effect the images have on the general public.
“A big highlight is having my images seen (and getting positive feedback from) people who don’t normally follow spaceflight activities,” Canvin said. “I only ever post images to UMSF but occasionally I’ll see referrals coming from non-spaceflight related sites where somebody has re-posted the link with a “hey this is cool, look at this” type message. It’s nice that I have been able to help get the word out to a few people who might not have known what was going on Mars otherwise. During my time at UMSF I’ve really come to appreciate the value of working to bring the amazing sights of the solar system to as wide an audience as possible.”
Ellison also spends a lot of his time doing talks about space exploration at schools, and is working on applying for grant to do more activities with schools and even science centers. He also has plans for ways to make the tools created by the UMSF participants more accessible to more people by creating a “Wiki.” “What I want to do is extract the material and the knowledge that’s there collectively into a specialized Wiki around the things that get discussed,” said Ellison. “That will turn our sometimes idle banter into a usable, citable reference tool.” This would certainly be a tremendous resource for photography and digital imaging aficionados.
I Heart Spacecraft
UMSF is a true love affair with the images produced by our robotic spacecraft. “I was talking with (British historian) Allan Chapman,” said Ellison, “and he said this is amateur in the true sense of the word because amateur means love. And that’s true because people love doing this. We do it because it’s an adventure and it’s exploration that we can do.”
UMSF participants have created special tools to enhance the experience, like the Midnight Mars Browser written by Mike Howard. What began as a simple tool to automatically grab images when they became available, has evolved into an interactive tool that will download and sort the images, produce color composites, stereo anaglyphs and even re-project the imagery into virtual 3D space so that Pancam and Navcam imagery can be seen in context, site by site, sol by sol.
Once you start, creating your own images can also become something close to an addiction. “There’s a genuine chance for you to look at a little piece of the Mars that no one has set eyes on before,” said Ellison. “And that’s an incredibly powerful thing. The process how the pictures go online is all automated, and you think, ‘I should go to bed now, but the images will hit the web in about an hour, so I’ll stay up and wait for the pictures.’ And you make a mosaic and put it on the forum and then a hundred people can see this little bit of Mars that no one else has seen before.”
While in some people’s minds, what’s being done at UMSF brings up questions about the fair use of raw images from mission websites, it seems to point to a possible future where amateurs and scientists work together for the common good. Doug Ellison's creation of the Columbia Hills using a combination of Hation of HiRISE images, rover images and a tool called Dreamscape.
“Scott Maxwell (MER rover driver – see our three part interview with Maxwell) and I share a vision for a Mars 3.0,” said Ellison. “Mars 1.0 is when you have to wait for the press to come out with a single picture from a mission. 2.0 is roughly where we are now, where all the pictures come out and anyone can look at them. Mars 3.0 is finding a way whereby the enthusiastic public can contribute back in. I thought the New Horizons ‘Kodak moment’ was an example that it can work. It’s not sensible to hand the rover driving gloves off to amateurs or anything like that, but there has to be some sort of middle ground where there’s a type of ‘audience participation’ that can be done. The sheer numbers in the amateur community and the massively wide range of abilities they posses, they can actually make a contribution back to the missions.”
Ellison said he doesn’t know how it will eventually turn out, or even if a true amateur/professional partnership is even possible because of things like ITAR (International Traffic in Arms Regulations) and other restrictive laws that NASA and JPL must abide by.
But in the meantime, there’s much to enjoy from UMSF, even for the digitally-challenged. “Anyone can come and enjoy the pictures and watch what we’re doing,” said Ellison. “I’ve always maintained that you don’t have to register just to look at the pictures. So, come and click on the latest about Opportunity and look at the next day, and you’ll see someone will update the map, someone will make a new mosaic, and someone will make a movie: it will all happen and you can watch it. Or if you think you can wield Photoshop, and if you think you have some ideas, give us a try. As long as you don’t go into the realm of crazy, we’ll share what we know with you.”
The ancient zodiacal constellation of Taurus was one of Ptolemy’s original 48 constellations and remains today as part of the official 88 modern constellations recognized by the IAU. It is perhaps one of the oldest constellations of all and may have even been recognized prehistorically. Taurus spreads over 797 square degrees of sky and contains 7 main stars in its asterism with 130 Bayer Flamsteed designated stars located within its confines. It is bordered by the constellations of Auriga, Perseus, Aries, Cetus, Eridanus, Orion and Gemini. Taurus is visible to all observers located at latitudes between +90° and ?65° and is best seen at culmination during the month of January.
There is one major annual meteor shower associated with the constellation of Taurus, the annual Taurids, which peak on or about November 5 of each year and have a duration period of about 45 days. The maximum fall rate for this meteor shower is about 10 meteors per hour average, with many bright fireballs often occuring when the parent comet – Encke – has passed near perihelion. Look for the radiant, or point of origin, to be near the Pleiades.
Taurus is considered by some to be one of the oldest recognized constellations known, and may have even been depicted with the Pleiades in cave paints dating back to 13,000 BC. According to Greek myth, Taurus was the god Zeus, transformed into a bull in order to woo princess Europa, and perhaps could represent one of the Cretean Bull of Herculean fame. The ancient Egyptians also worshiped a bull-god for which this constellation might represent, just as the Arabs also considered it to be bovine by nature. The Hyades cluster was meant to represent the sisters of Hyas, a great hunter, placed in the sky to honor their mourning for the loss of their brother – just as the Pleiades represent the seven sisters of Greek mythology – as well as many other things in many other cultural beliefs. The Persians called this group of stars “Taura”, just as the Arabs referred to it as “Al Thaur”. No matter what way you want to look at it, this handsome collection of stars contains many fine deep sky objects to pique your interest!
Let’s begin our binocular and telescope tour of Taurus with its brightest star- Alpha – the “a” symbol on our map. Known to the Arabs as Al Dabaran, or “the Follower,” Alpha Tauri got its name because it appears to follow the Pleiades across the sky. In Latin it was called Stella Dominatrix, yet the Olde English knew it as Oculus Tauri, or very literally the “eye of Taurus.” No matter which source of ancient astronomical lore we explore, there are references to Aldebaran.
As the 13th brightest star in the sky, it almost appears from Earth to be a member of the V-shaped Hyades star cluster, but this association is merely coincidental, since it is about twice as close to us as the cluster is. In reality, Aldebaran is on the small end as far as K5 stars go, and like many other orange giants, it could possibly be a variable. Aldebaran is also known to have five close companions, but they are faint and very difficult to observe with backyard equipment. At a distance of approximately 68 light-years, Alpha is “only” about 40 times larger than our own Sun and approximately 125 times brighter. To try to grasp such a size, think of it as being about the same size as Earth’s orbit! Because of its position along the ecliptic, Aldebaran is one of the very few stars of first magnitude that can be occulted by the Moon.
Now, head off to Beta Tauri – the “B” symbol on our chart. Located 131 light years from our solar system, El Nath, or Gamma Aurigae, is a main sequence star about to evolve into a peculiar giant star – one high in manganese content, but low in calcium and magnesium. While you won’t find anything else spectacular about El Nath, there is a good reason to remember its position – it, too, get frequently occulted by the Moon. Such occultations occur when the moon’s ascending node is near the vernal equinox. Most occultations are visible only in parts of the Southern Hemisphere, because the star lies at the northern edge of the lunar occultation zone and occasionally it may be occulted as far north as southern California.
Now, turn your binoculars or small telescopes towards Omicron – the “o”. Omicron is sometimes called Atirsagne, meaning the “Verdant One”, but there’s nothing green about this 212 light year distant yellow G-type giant star, only that it has a great optical companion! Be sure to take a look at Kappa Tau, too… the “k”. Kappa is also a visual double star – but a whole lot more. Located 153 light years from Earth, this Hyades cluster member is dominated by white A-type subgiant star K1 and white A-type main sequence dwarf star, K2. They are 5.8 arcminutes, or at least a quarter light year apart. Between the two bright stars is a binary star made up of two 9th magnitude stars, Kappa Tauri C and Kappa Tauri D, which are 5.3 arcseconds from each other and 183 arcseconds from K1 Tau. Two more 12th magnitude companions fill out the star system, Kappa Tauri E, which is 136 arcseconds from K1 Tau, and Kappa Tauri F, 340 arcseconds away from K2 Tau. Still more? Then have a look at 37 Tauri, an orange giant star with a faint optical companion star… or 10 Tauri! 10 Tauri is only 45 light years away, and while it just slightly larger and brighter than our Sun, its almost the same age. It is believed to be a spectroscopic binary star, but you’ll easily see it’s optical companion. What’s more, thanks to noticing a huge amount of infrared radiation being produced by 10, we know it also has a dusty debris disk surrounding it!
Now, let’s have a go at variable stars – starting with Lambda, the upside down “Y” on our map. Al Thaur is in reality a binary star system as well as being an eclipsing variable star. The primary is a blue-white B-type main sequence dwarf star located about 370 light years away. However, located at a distance of 0.1 AU away from it is a white A-type subgiant star, too… and a third player even further away. Watch over a period of 3.95 days as first one, then the other passes in front of the primary star, dimming it by almost a full stellar magnitude! Don’t forget to check out HU Tauri, too. It is also an eclipsing binary star that drops by a magnitude every 2.6 days!
Ready to take a look at Messier 45? Visible to the unaided eye, small binoculars and every telescope, the Pleiades bright components will resolve easily to any instrument and is simply stunning. The recognition of the Pleiades dates back to antiquity and they’re known by many names in many cultures. The Greeks and Romans referred to them as the “Starry Seven,” the “Net of Stars,” “The Seven Virgins,” “The Daughters of Pleione” and even “The Children of Atlas.” The Egyptians referred to them as “The Stars of Athyr,” the Germans as “Siebengestiren” (the Seven Stars), the Russians as “Baba” after Baba Yaga, the witch who flew through the skies on her fiery broom. The Japanese call them “Subaru,” Norsemen saw them as packs of dogs and the Tongans as “Matarii” (the Little Eyes). American Indians viewed the Pleiades as seven maidens placed high upon a tower to protect them from the claws of giant bears, and even Tolkien immortalized the stargroup in The Hobbit as “Remmirath.” The Pleiades have even been mentioned in the Bible! So, you see, no matter where we look in our “starry” history, this cluster of seven bright stars has been part of it.
The date of the Pleiades culmination (its highest point in the sky) has been celebrated through its rich history by being marked with various festivals and ancient rites — but there is one particular rite that really fits this occasion! What could be spookier on this date than to imagine a bunch of Druids celebrating the Pleiades’ midnight “high” with Black Sabbath? This night of “unholy revelry” is still observed in the modern world as “All Hallows Eve” or more commonly as “Halloween.” Although the actual date of the Pleiades’ midnight culmination is now on November 21 instead of October 31. Thanks to its nebulous regions M45 looks wonderfully like a “ghost” haunting the starry skies. Binoculars give an incredible view of the entire region, revealing far more stars than are visible with the naked eye. Small telescopes at lowest power will enjoy M45’s rich, icy-blue stars and fog-like nebulae. Larger telescopes and higher power reveal many pairs of double stars buried within its silver folds. No matter what you chose, the Pleiades definitely rocks!
Our next most famous Messier catalog object in Taurus is M1 – the “Crab Nebula”. Although M1 was discovered by John Bevis in 1731, it became the first object on Charles Messier’s astronomical list. He rediscovered M1 while searching for the expected return of Halley’s Comet in late August 1758 and these “comet confusions” prompted Messier to start cataloging. It wasn’t until Lord Rosse gathered enough light from M1 in the mid-1840’s that the faint filamentary structure was noted (although he may not have given the Crab Nebula its name). To have a look for yourself, locate Zeta Tauri and look about a finger-width northwest. You won’t see the “Crab legs” in small scopes – but there’s much more to learn about this famous “supernova remnant”.
Factually, we know the “Crab Nebula” to be the remains of an exploded star recorded by the Chinese in 1054. We know it to be a rapid expanding cloud of gas moving outward at a rate of 1,000 km per second, just as we understand there is a pulsar in the center. We also know it as first recorded by John Bevis in 1758, and then later cataloged as the beginning Messier object – penned by Charles himself some 27 years later to avoid confusion while searching for comets. We see it revealed beautifully in timed exposure photographs, its glory captured forever through the eye of the camera — but have you ever really taken the time to truly study the M1? Then you just may surprise yourself… In a small telescope, the “Crab Nebula” might seem to be a disappointment – but do not just glance at it and move on. There is a very strange quality to the light which reaches your eye, even though at first it may just appear as a vague, misty patch. To small aperture and well-adjusted eyes, the M1 will appear to have “living” qualities – a sense of movement in something that should be motionless. This aroused my curiosity to study and by using a 12.5″ scope, the reasons become very clear to me as the full dimensions of the M1 “came to light”.
The “Crab” Nebula holds true to so many other spectroscopic studies I have enjoyed over the years. The concept of differing light waves crossing over one another and canceling each other out – with each trough and crest revealing differing details to the eye – is never more apparent than during study. To truly watch the M1 is to at one moment see a “cloud” of nebulosity, the next a broad ribbon or filament, and at another a dark patch. When skies are perfectly stable you may see an embedded star, and it is possible to see six such stars. It is sometimes difficult to “see” what others understand through experience, but it can be explained. It is more than just the pulsar at its center teasing the eye, it is the “living” quality of which I speak -TRUE astronomy in action. There is so much information being fed into the brain by the eye!
I believe we are all born with the ability to see spectral qualities, but they just go undeveloped. From ionization to polarization – our eye and brain are capable of seeing to the edge of infra-red and ultra-violet. How about magnetism? We can interpret magnetism visually – one only has to view the “Wilson Effect” in solar studies to understand. What of the spinning neutron star at its heart? We’ve known since 1969 the M1 produces a “visual” pulsar effect! We are now aware that about once every five minutes, changes occurring in the neutron star’s pulsation effect the amount of polarization, causing the light waves to sweep around like a giant “cosmic lighthouse” and flash across our eyes. For now, l’ll get down of my “physics” soapbox and just let it suffice to say that the M1 is much, much more than just another Messier. Capture it tonight!!
Since we’ve studied the “death” of a star, why not take the time tonight to discover the “birth” of one? Get out your telescope! Our journey will start by identifying Aldeberan (Alpha Tauri) and moving northwest to bright Epsilon. Hop 1.8 degrees west and slightly to the north for an incredibly unusual variable star – T Tauri. Discovered by J.R. Hind in October 1852, T Tauri and its accompanying nebula, NGC 1554/55 set the stage for discovery with a pre-main sequence variable star. Hind reported the nebula, but also noted that no catalog listed such an object in that position. His observance also included a 10th magnitude uncharted star and he surmised that the star in question was a variable. On either account, Hind was right and both were followed by astronomers for several years until they began to fade in 1861. By 1868, neither could be seen and it wasn’t until 1890 that the pair was re-discovered by E.E. Barnard and S.W. Burnham. Five years later? They vanished again.
T Tauri is the prototype of this particular class of variable stars and is itself totally unpredictable. In a period as short as a few weeks, it might move from magnitude 9 to 13 and other times remain constant for months on end. It is about average to our own Sun in temperature and mass – and its spectral signature is very similar to Sol’s chromosphere – but the resemblance ends there. T Tauri is a star in the initial stages of birth! So what exactly are T Tauri stars? They may be very similar in ways to our own Sun but they are far more luminous and rotate much faster. For the most part, they are located near molecular clouds and produce massive outflows of this material in accretion as evidenced by the variable nebula, NGC 1554/55. Like Sol, they produce X-ray emissions, but a thousand times more strong! We know they are young because of the spectra – high in lithium – which is not present at low core temperatures. T Tauri has not reached the point yet where proton to proton fusion is possible! Perhaps in a few million years T Tauri will ignite in nuclear fusion and the accretion disk become a solar system. And just think! We’re lucky enough to see them both…
For a large telescope challenge, let’s try NGC 1514 (RA 4 : 09.2 +30 : 47). This magnitude 10 planetary nebula is fairly small and dim… and it was discovered by William Herschel on November 13, 1790. If he could do it over 300 years ago, so can you! Chances are this particular nebula is a gaseous envelope which surrounds a tight double star, but revealing it was what startled Herschel the most. In his reports he writes: “A most singular phenomena… surrounded with a faintly luminous atmosphere… judgement I may venture to say, will be, that the nebulosity about the star is not of a starry nature”.
Planetary nebulae were first described as “planetary” by William Herschel in 1785. Before then, all were simply considered “nebulae.” It was once thought they were made of stars, but today we know planetaries are created from material given off by a single star. Many show well-defined rings of one type or another. Others – like M1 – are irregularly shaped supernova remnants. NGC 1514’s material is slowly boiled off over time, rather than caused by a violent explosion. It would be very hard to find the neutron central star in M1, but almost any scope can make out NGC 1514’s 10th magnitude fueling star as it quietly cooks away gases to feed its nebulous shroud. Because it is so bright, it can easily overwhelm the eye. This makes NGC 1514 similar to the famous “Blinking Planetary” – NGC 6826 – in Cygnus.
Are you ready for some galactic star clusters? Then let’s head for NGC 1647 (RA 4 : 46.0 Dec +19 : 04). At nearly unaided eye visibility and large enough to be easily seen in small binoculars and telescope, this widely scattered star cluster contains several dozen well resolved members and lots of double stars. The brighter stars are A or B-type main sequence stars, however there are also a few colorful orange giants to delight the eye, and the two brightest are located on the southern edge of the cluster.
Another bright, big and beautiful open star cluster for all optics is NGC 1746 (RA 5 : 03.6 Dec +23 : 49). It contains about two dozen members and although its not very compressed to the telescope, makes a very nice showing in binoculars or a rich field telescope. What’s clever about this particular cluster, is there is also two other open clusters which are superimposed on top! Look for NGC 1750 and NGC 1758 as part of this region as well. While it was debated for many years that Sir William Herschel was crazy when he designated three separate clusters for this region, later science proved him right!
How about another pair of open star clusters? Then have a look at NGC 1817 (RA 5 : 12.1 Dec +16 : 42) and NGC 1807 (RA 5 : 10.7 Dec +16 : 32). Both can be squeezed in the same field in binoculars and resolved very well to the telescope. Found a little less than a hand span northwest of Betelguese, NGC 1807 and NGC 1817 aren’t exactly twins. Both clusters are of similar magnitude and can be seen as faint patches in binoculars. Through a telescope, NGC 1817 appears far more populated with stars than its neighbor. Studies based on stellar motion reveal that NGC 1817 has far more stars than the brighter NGC 1807. Although the two are quite distant from one another in space, we get to see them both as close friends…
Washington D.C. from orbit. The Google Satellile GeoEye-1 will spy on Obama's inauguration (Google)
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President-elect Barack Obama’s inauguration on Capitol Hill will be the place-to-be on Tuesday (January 20th). According to some news sources, tickets for the event were trading for a price exceeding 5 figures (in one case, according to CNN in November, an online vendor was asking for $20,095 for a single ticket – I hope they get a “free” bottle of Champagne with that!). It would appear that ticket demand outstripped supply, making the 44th presidential inauguration one of the hottest (and most costly) events to attend in 2009.
However, there is a far cheaper (and less crowded) alternative to view Obama and Biden getting sworn into office. A satellite called GeoEye-1 will be orbiting 423 miles above Washington D.C. looking down at the vast crowd minutes before the excitement begins…
GeoEye-1 launch on September 6th 2008 (Reuters)In August 2008, Google signed a deal with the satellite imagery company GeoEye for exclusive use of the images produced by the company’s new GeoEye-1 satellite. GeoEye-1 was launched on board a United Launch Alliance Delta II rocket from Vandenberg Air Force Base, California, on September 6th 2008. The satellite is currently in a Sun-synchronous orbit, over 400 miles above the surface of Earth, imaging the surface in unprecedented detail. A US government licence actually limits the resolution of available images to 0.5 metres (the camera on GeoEye-1 can attain a resolution of 0.41 metres). GeoEye-1’s competitors can resolve objects down to 0.6 metres at the smallest. The GeoEye products are currently used by Google for several projects, such as Google Earth and Google Maps.
On Tuesday, however, it is not Google that is interested in getting the ultimate birds-eye view of the festivities at Capitol Hill; GeoEye itself is commissioning a high-resolution photography run at 11:19 EST as the satellite buzzes overhead at a speed of 17,000 mph. Usually, the presidential inauguration takes place at noon, so GeoEye-1 will be able to grab a snapshot of the growing crowds of spectators 41 minutes before the new commander-in-chief takes office.
“An image of the Inauguration has been requested by many news organizations,” a GeoEye spokesperson said. “So, if the weather cooperates, the image will be distributed to news organizations and bloggers around the world. The image will be available about three hours after it’s taken.”
I for one, will be hovering over the GeoEye website, waiting for the orbital view of Washington D.C. to appear in the comfort of my office…
[/caption]Naming Pluto explores the chain of events that lead to Pluto’s naming and in 2007 sees Venetia Phair viewing Pluto for the very first time through a telescope, on her 89th birthday, 77 years after Pluto’s discovery. A wonderful, intimate look into the story behind how Pluto got its name. A review of the short film directed and produced by Ginita Jimenez, distributed by Father Films.
In recent years, Pluto has seen its status change from being a planet to what many people view as a planetary underclass. The reasons behind this have been set out by the International Astronomical Union (IAU) to cater for the increasing number of Solar System bodies being discovered; the traditional nine planets have had to make room for a growing minor planet population. Unfortunately, Pluto was at the front line as it inhabits a region of space dominated by the gas giant Neptune, plus thousands of other Kuiper belt objects. Although the mysterious body lost its planetary status (as it does not have the ability to “clear its own orbit”), it has taken the title of “dwarf planet” and now has an entire class of object named in its honour: “Plutoids”.
However, the recent tumultuous history of the traditional “9th planet” has not impacted the fascination we have for Pluto. It has, and always will be, viewed with intrigue and wonder.
The key to Pluto’s romantic tale begins in the year 1930 when a mysterious heavenly was discovered by Clyde Tombaugh, a 23 year-old astronomer working at the Lowell Observatory in Flagstaff, Arizona. However, the honour of naming Pluto didn’t rest on Tombaugh’s shoulders. Over 5000 miles away in Oxford (UK) an 11 year old girl was having breakfast with her grandfather, wondering what this newly discovered planet should be called…
The Pluto system seen from the surface of Hydra (NASA)Naming Pluto starts out with some stunning visuals from 2006 of NASA’s New Horizons Pluto mission launching from Cape Canaveral. Throughout the opening tour of the Solar System, we can hear the voice of Venetia Burney as she is interviewed by NASA Public Affairs officer Edward Goldstein during the launch.
When Goldstein asks whether she had ever seen Pluto through a telescope, the clear and articulate voice of Venetia replies, “I don’t think I have. I’ve just seen a photograph.” And so the journey begins, where Venetia explains her fascination with Pluto and a number of experts (including the enigmatic Sir Patrick Moore) help to explain the facts behind the discovery of Pluto to the scientific endeavour of the search for “Planet X”.
One of the key moments is when Venetia is describing when she decided on the name for the heavenly body. At age 11, had an acute interest in ancient mythology, so she chose the name because Pluto is the Roman god of the underworld; a fitting name considering the cold, dark nature of Pluto’s 248 year orbit. In a fortuitous chain of events, her grandfather, a former librarian of Oxford University’s Bodleian Library, passed the suggestion via letter to Professor Herbert Hall Turner saying that his granddaughter had chosen a “thoroughly suitable name: PLUTO.” Hall Turner, thrilled with the candidate name, sent Venetia’s idea to colleagues in the USA, at the Lowell Observatory.
A special delight is when Venetia visits St. Anne’s Primary School in Surrey to participate in their class project all about Pluto. It goes to show that even young school children have fallen under Pluto’s spell. One 9 year-old pupil, Katie, shares her concerns about Pluto’s demotion, “Some people say that Pluto isn’t a real planet, so I’m looking forward to Venetia coming because I want to find out if that’s true.”
Other guests on the film uncover the various attributes of Pluto’s discovery, delving into the history and future of the planetary lightweight on the outermost reaches of the Solar System.
“Yes, indeed,” the ever gracious Venetia replies, smiling.
Unfortunately, the UK summer weather conspired against the possibility of clear skies, and any chance of Patrick’s 15″ reflector of spying Pluto was lost. However, there is a fantastic twist in the tale, bringing the whole film to a wonderfully emotional ending.
All in all, Naming Pluto is a fabulous tribute, not only to Venetia, but to the astronomical process. Although Pluto has undergone a change in status these last few years, it remains an important, permanent feature of the Solar System. This well-crafted story gives the viewer an excellent overview of Pluto’s discovery, naming and the magic it holds today for the 9 year-olds at St. Anne’s to Venetia who named the planet nearly 80 years ago…
A big thank you goes to writer, director and producer Ginita Jimenez for sharing this magnificent production with me. My copy will have pride of place with my growing collection of space science DVDs, a timeless memento of a historic time for astronomy.
If you want your own copy, or want to buy it as a gift, contact Ginita at: [email protected]
Naming Pluto is currently on the international film festival circuit so if you’d prefer watching it on the big screen, and are in the area, please see below. There will also be a blog and updates on www.fatherfilms.com.
THROUGH WOMEN’S EYES – USA
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30TH & 31ST JANUARY 2009
JAIPUR INTERNATIONAL FILM FESTIVAL – INDIA
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FEB/MARCH 2009
SEBASTOPOL DOCUMENTARY FILM FESTIVAL – USA
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MARCH 6-8, 2009
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FEB 25-MAR 08 2009
OFFICIAL SELECTION FOR BEST SHORT FILM AWARD
A Mini-SAR strip overlain on an Earth-based, Arecibo Observatory radar telescope image. Taken Nov. 17, 2008, the south-polar SAR strip shows a part of the moon never seen before: a portion of Haworth crater that is permanently shadowed from Earth and the sun. Credit: ISRO/NASA/JHUAPL/LPI/Cornell University/Smithsonian
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A few “new” images have been released from the Chandrayaan-1 lunar orbiter mission. The latest are the first images from NASA’s radar instrument that’s hitching a ride on board the Indian Space Research Organization’s (ISRO) spacecraft. Called the Mini-SAR (synthetic aperture radar), NASA’s instrument recently passed initial in-flight tests and sent back its first data from Nov. 17, 2008, showing the first look inside one of the Moon’s coldest, darkest craters. The image above shows a swath from the Mini-SAR overlaid on a ground-based telescope image of Haworth Crater. The swath shows the floor of this permanently-shadowed polar crater on the moon that isn’t visible from Earth. The instrument will map both polar regions to search the insides of craters for water ice.
“The only way to explore such areas is to use an orbital imaging radar such as Mini-SAR,” said Benjamin Bussey, deputy principal investigator for Mini-SAR, from the Johns Hopkins University Applied Physics Laboratory. “This is an exciting first step for the team which has worked diligently for more than three years to get to this point.”
Bright areas represent surface roughness or slopes pointing toward the spacecraft. The data cover an area approximately 50 kilometers (31 miles) by 18 kilometers (11 miles). The two north-polar strips have been mosaicked to show the western rim of Seares crater.Credit: ISRO/NASA/JHUAPL/LPI Click for larger image
Two more radar swaths from the Moon’s north pole have been stitched together to show the western rim of Seares crater. The mosaic covers an area roughly 80 kilometers (50 miles) long by 20 kilometers (12.5 miles) wide.
“During the next few months we expect to have a fully calibrated and operational instrument collecting valuable science data at the moon,” said Jason Crusan, program executive for the Mini-RF Program, which also includes a radar instrument on the upcoming Lunar Reconnaissance Orbiter mission
Mini-SAR is one of 11 instruments on Chandrayaan 1. Not setting any speed records in making the images available to the public, a few other images were recently released that were also taken in November 2008. Mission managers have had to deal with the spacecraft overheating slightly due to orbiting in almost continual sunlight, and therefore they decided to use only one instrument at a time. Normal operations should begin soon, where all the instruments will be able to function normally and together. Moon 3D from the TMC. Credit: ISRO
This Digital Elevation Model of the lunar surface was generated by using imagery from India’s Terrian Mapping Camera. The TMC will map topography on both sides of the Moon and prepare a 3-dimensional atlas with high spatial and altitude resolution. Lunar crater from the TMC. Credit: ISRO
This image, also from the TMC, shows details of a lunar crater. 3D anaglyph from the TMC. Credit: ISRO
Here’s one of several 3D images of different regions of lunar surface captured by TMC. By looking through 3D glasses, you get a grasp of the height of features shown here. More 3D anaglyph images are available on the ISRO site.
Chandrayaan-1 launched from India on Oct. 21, 2008 and began orbiting the moon Nov. 8.
Located just south of the ecliptic plane, the small, dim constellation of Sextans was originally introduced in the 17th century by astronomer Johannes Hevelius. It covers 314 square degrees of sky and ranks 47th in constellation size. Sextans has 3 primary stars in its asterism and 28 Bayer Flamsteed designated stars within its confines. It is bordered by the constellations of Leo, Hydra and Crater. Sextans is visible to all observers located at latitudes between +80° and ?80° and is best seen at culmination during the month of April.
There is one annual meteor shower associated with Sextans which occurs during the daytime. The Sextantids begin their activity on or about September 9 and last through October 9 of each year with the peak date occurring on or about September 27. This daytime radio meteor stream can produce up to three or four per hour at maximum rate.
Since Sextans is considered a relatively “new” constellation, it has no mythology associated with it – only the object which it represents. Its original name – Sextans Uranae – is Latin for the astronomical sextant, an instrument which Johannes Hevelius made frequent use of in his stellar observations. Although the constellation is very faint, its angles do resemble this particular tool with which the ancient astronomer measured and charted star positions and it was adopted as the constellation Sextans by the International Astronomical Union as one of the 88 modern constellations.
Let’s begin our binocular tour with its brightest star – Alpha – the “a” symbol on our map. Just barely visible to the unaided eye and standing right on the celestial equator, Alpha Sextantis shines 122 times brighter than our Sun and is about 3 times larger. Little wonder it appears so dim, considering that its about 285 light years from Earth! At an estimated 300 million years old, Alpha is nearing the end of its hydrogen fusing lifetime and is about to become an orange giant star – one with its pole pointed right at us. Take note of Alpha’s position in the sky… Because thanks to Earth’s nutation, it was 7 arc seconds more to the north a century ago!
Now, shift your attention towards Beta – the “B” symbol. Beta is a a blue-white B-type main sequence dwarf star located about 345 light years from our solar system. While it looks very ordinary… It isn’t. Beta is a Alpha 2 Canum Venaticorum variable star – one that varies its magnitude ever so slightly just about every 15 days or so.
Ready to go to the telescope? Then aim it at Gamma – the “Y” symbol on our chart. Gamma Sextantis is a triple star system approximately 262 light years from Earth. Its two primary components, A and B, are approximately 0.38 arcseconds apart or approximately 30 Astronomical Units With apparent magnitudes of +5.8 and +6.2 this close proximity means you better have a big telescope and some super resolution to pull this pair apart! However, orbiting the binary star pair at a distance of 36 arcseconds, or roughly a hundred times farther out, is Gamma Sextantis C, a 12th magnitude companion that is also gravitationally bound to the system. Faint… But far enough away to be seen!
Before you give up on Sextans, be sure to turn your telescope or big binoculars towards NGC 3115 (RA 10 : 05.2 Dec -07 : 43). With a magnitude of 9 and more than 8 arc minutes of size, the “Spindle Galaxy” is sure to please everyone! This lenticular galaxy was discovered by William Herschel on February 22, 1787. At about 32 million light-years away from us, it might not look large in the eyepiece, but in reality it is several times bigger than our own Milky Way Galaxy. In 1992, a supermassive black hole was observed in NGC 3115 – the largest found to that date. With an estimated mass of 2 billion times the mass of the Sun, astronomers have kept a close eye on activity since its discovery. The galaxy itself appears to be comprised of mostly old stars and the growth of the black hole hasn’t increased in size since it was first observed.
The Chandra X-Ray Telescope has maintained its vigil and according to its press releases: “This is the best black hole candidate that is massive enough to have powered a quasar.”
These findings strengthen the popular view that quasars – the brightest objects in the Universe – are powered by accretion onto massive black holes. Quasars can be seen farther away than any other object. In many cases, their light has been traveling toward us for most of the age of the Universe. Therefore we see quasars as they were long ago. As a result, astronomers can infer how the quasar population evolved with time. They find that quasars were numerous when the Universe was 1/4 of its present age. Now they have mostly died out. So dead quasars should be hiding in many nearby galaxies. Quasar energies imply that the dead remnants should have masses of a billion Suns. The discovery of a supermassive black hole is a crucial confirmation of the black hole accretion theory of quasars.
Ironically, NGC 3115 is otherwise undistinguished. It’s name comes from its listing as object number 3115 in J. Dreyer’s “New General Catalog” of nebulae and star clusters, published in 1888. The galaxy is visible in moderate-sized amateur telescopes as a faint fuzzy patch in the constellation Sextans, The Sextant. But at a distance of 30 million light years, NGC 3115 is more than ten times farther from us than Andromeda or M32. In reality, it is several times bigger than our own Milky Way. But its stars are mostly old, it contains virtually no gas, and little is going on now apart from the stately orbits of its stars. In particular, its nucleus is extremely inactive. The growth of the black hole and the nuclear activity that it feeds are over, unless additional stars wander too close to the center. Whenever that happens, the nucleus is expected to experience a brief but energetic rebirth.
Although these findings support our general picture of quasars, they also highlight a number of unresolved issues. “We have only a very speculative idea of how supermassive black holes form,” Richstone said. “The processes that control their feeding, make them shine, and later turn them off are also poorly understood.” Finding nearby black holes is crucial to further progress. NGC 3115 provides a billion-solar-mass example.”
