This false-color composite image, taken with the Hubble Space Telescope, reveals the orbital motion of the planet Fomalhaut b. Credit: NASA, ESA, and P. Kalas (University of California, Berkeley and SETI Institute)
Fomalhaut is a really cool place to study. The naked-eye star (the brightest star in the constellation Piscis Austrinus) has a planet, Fomalhaut b, that once appeared dead but rose again in science circles. It is the site of a comet massacre. Now it’s getting even more interesting: Scientists have believed for years that Fomalhaut is a double star, but a new paper proposes that it is actually a triplet.
“I noticed this third star a couple of years ago when I was plotting the motions of stars in the vicinity of Fomalhaut for another study,” stated Eric Mamajek, associate professor of physics and astronomy at the University of Rochester. The third star is known as LP876-10 or Fomalhaut C.
“However, I needed to collect more data and gather a team of co-authors with different observations to test whether the star’s properties are consistent with being a third member of the Fomalhaut system.”
That opportunity came when Mamajek was in Chile and by chance, talking with Georgia State University’s Todd Henry, who is the director of the Research Consortium on Nearby Stars. A student (who has now graduated), Jennifer Bartlett at the University of Virginia, was working on a study of potential nearby stars for her Ph.D. thesis, which included the star that Mamajek was curious about.
Herschel’s far-infrared observations of Fomalhaut and its disk. Credit: ESA
The team plotted the star’s movements and spectroscopy (to see its temperature and radial velocity) and concluded the speed and distance of the star matched that of the Fomalhaut system.
LP876-10/Fomalhaut C is a red dwarf that appears the distance of 11 full moons apart from Fomalhaut in the night sky. It seems counterintuitive to believe they are close together, but the team reminds us that Fomalhaut is very close to us as stars go: 25 light-years away.
“That they appear so far apart could explain why the connection between LP 876-10 and Fomalhaut had been previously missed,” the team stated.
Image of a galaxy with rendering showing a stream of inflowing gas, as rendered in a supercomputer. Credit: MPIA (G. Stinson / A.V. Maccio)
“Primordial hydrogen” sounds like a great name for a band. It’s also a great thing to find when you’re looking at a galaxy. This ancient gas is a leftover of the Big Bang, and astronomers discovered it in a faraway star-forming galaxy that was created when the universe was young.
A continuous stream of gas was likely responsible for a cornucopia of star formation that took place about 10 billion years ago, when galaxies were churning out starbirths at a furious rate.
The astronomers spotted the gas by using a quasar that lit up the fuel from behind. Quasars a handy tool to use if you want to illuminate something, because even though quasars don’t live for very long in cosmic terms — they occur when matter falls into a ginormous black hole — they are extremely bright. Since the gas absorbs the light at certain frequencies, the absorption lines that show up in spectrometers reveal information about the composition, temperature and density of the gas.
“This is not the first time astronomers have found a galaxy with nearby gas, revealed by a quasar. But it is the first time that everything fits together,” stated Neil Crighton, who is with the Max Planck Institute for Astronomy and Swinburne University and led the research. His team found the galaxy using the Keck I telescope in Hawaii.
“The galaxy is vigorously forming stars,” added Crighton, “and the gas properties clearly show that this is pristine material, left over from the early universe shortly after the Big Bang.”
Q1442-MD50 (as the galaxy is called) is 11 billion light years away from us — pretty close to the start of the universe about 13.8 billion years ago. The quasar that lit it up is called QSO J1444535+291905.
“Since this discovery is the result of a systematic search, we can now deduce that such cold flows are quite common,” stated Joseph Hennawi, the leader of the ENIGMA research group at the Max Planck Institute for Astronomy. “We only had to search 12 quasar-galaxy pairs to discover this example. This rate is in rough agreement with the predictions of supercomputer simulations, which provides a vote of confidence for our current theories of how galaxies formed.”
You can read more details in the article (which is in Astrophysical Letters) or in this preprint version on Arxiv.
No, this isn’t The Onion… as a concerned consumer of all that is space news, you have indeed arrived at the cyber-doorstep of Universe Today.
I’ll admit though, that we did do a double take about a week back when a peculiar claim came our way via the Iranian Space Agency. Yes, there is an Iranian Space Agency, and it’s kind of frightening that they remain open for business while NASA is largely shutdown.
In mid-September, senior Iranian space program official Mohammad Ebrahimi issued a statement that Iran will attempt another bio-capsule launch “within 45 days”. The unwilling occupant: a Persian cat.
Apparently, a rabbit, a mouse, and another “Space Monkey” were also in the running. Iran’s space program is shrouded in secrecy, and most launches are only announced after they’ve been conducted. This is a convenient political strategy for hiding launch failures that harkens back to the early days of the Cold War. You’re right in guessing that the Iranian Space Agency probably won’t hold a Tweetup for this one. Many western analysts see the Iran’s space effort as a thinly veiled attempt to develop its long range ballistic missile technology. Along with Israel, Iran remains the only Middle Eastern country with the proven technology to conduct indigenous satellite launches.
Iran has stated that it hopes to put an astronaut in orbit by 2019. The Pishgam (or “Pioneer” in Farsi) 2 bio-capsule launch could occur from a mobile launcher at Semnan Space Center as early as October 15th. Satellite sleuths are also expecting activity at Semnan to pick up this month, with the possible launch of SharifSat atop a Safir 1-B rocket, and Iran’s Toulou satellite aboard a rumored new launch vehicle.
Iran successfully became a space-faring nation with the launch of its 27 kilogram Omid satellite on February 2nd, 2009. It isn’t immediately clear if the upcoming launch will be an orbital launch or a sub-orbital ballistic shot. If Pisgam-2 achieves orbit, said “Space Cat” would become the first feline to circle the Earth. If recovery is attempted —again, Iran is always nebulous as to their intentions— it would also be the first time they’ve achieved a return from orbit.
But is “Space Cat” even a reality?
Iran has been caught red-handed before playing a shell game with the media in terms of its space program. Earlier this year, “Monkey-gate” erupted, as before-and-after images from the Pisgam-1 bio-capsule suborbital launch clearly showed two different monkeys before and after the flight:
Monkey business? Iran displayed a decidedly different looking monkey before, during, and after launch earlier this year! (Credit: Iran News Agency).
Clearly, Iran and other ‘Axis of Evil’ countries definitely need to sharpen their Photoshop, or at least their monkey-switching skills. Either said monkey launch never actually occurred, or (more likely), the unwilling Iranian space primate never survived the flight.
Perhaps this is why Iran decided on a feline occupant this time around, for possible ease of replacement?
PETA, the People for the Ethical Treatment of Animals, have also issued a statement concerning the impending launch of “Space Cat” by Iran, calling the action an “archaic experiment, a throwback to the primitive techniques of the 1950’s.”
NASA did entertain the idea of “Catronauts” early in the space program. (Credit: NASA).
The U.S. and the Soviet Union launched animals into space as a prelude to human spaceflight. On November 3rd, 1957, Laika the dog became the first animal to orbit the Earth. Laika perished is space due to overheating, as did several unfortunate monkeys that were launched on the first US ballistic tests.
Russia still conducts the occasional launch of animals into space, including the Bion-1M “Space Zoo” mission earlier this year. The Bion missions allow for scientists to dissect the specimens afterwards to study the effects of a month in zero-g, something you can’t do with humans.
And the U.S. did once fly cats in zero-g aboard its Convair C-131 “Vomit Comet” aircraft, as can be seen in this bizarre video:
But the first cat in space was actually launched by France atop a Veronique AGI sub-orbital rocket 50 years ago this month on October 18th, 1963. It would be ironic if Iran conducted it launch this month on the anniversary! The story goes the Felix, the original cat slated for the flight, escaped just prior to launch from the Sahara desert Hammaguir test site in Algeria, and was replaced by the “backup crew,” a female cat named Felicette. Felicette survived the 15 minute flight, reaching an apogee of 217 kilometres. A follow-up launch of a second cat six days later wasn’t so lucky.
Felicette (left) and Felix in publicity shots prior to launch. Note the cranial electrode (!) implants. (Credit: Marjorie-art Voila.net)
As always, Iran’s intentions for the future of its space program remain hidden. Their current launch capabilities remain limited, and are a far cry from being able to hoist a human into orbit anytime soon. If the launch of “Space Cat” does come to pass this month, it’ll be over protests from animal rights groups and the general public. Hey, didn’t the former Iranian president Mahmoud Ahmadinejad say earlier this year after “Monkey-Gate” that he was willing to be “The first Iranian to be sacrificed by the scientists of my country and go into space” as the first Iranian astronaut? Is he really going to let Space Cat upstage him?
Felix and Felicette where also commemorated on several African postage stamps. (Credit: Majorie-art.voila.net).
–Read a great synopsis of the history of felines in space from Heather Archulletta @Pillownaut.
Images of aurora in Alaska captured by two digital SLRs. Differences in the left and right pictures allow researchers to measure at what altitude the electrons were. Credit: Kataoka et al., 2013
Ever stood outside looking at the aurora and felt as though it was swirling just a short distance above your head? It’s hard to judge altitude when looking at sky phenomena because there are few landmarks above us. (The moon effect at the horizon is an example.) But it turns out there is a way to measure aurora altitude.
The eerie, green glow of the Northern Lights swirls about in the video you see above. A group of researchers used a unique but simple technique to measure how high the electrons were during the dazzling light display: they mounted two digital SLRs eight kilometers (five miles) apart in Alaska, and used that old astronomical friend, parallax, to measure distances.
“Using the parallax of the left-eye and the right-eye images, we can calculate the distance to the aurora using a [triangulation] method that is similar to the way the human brain comprehends the distance to an object,” stated Ryuho Kataoka, an associate professor at the National Institute of Polar Research in Japan. “Parallax is the difference in the apparent position of an object when observed at different angles.”
Altitude measurements have been done before using this technique, but it’s the first time digital SLRs were employed, the research team said. A typical aurora has electrons that are between 90 kilometers and 400 kilometers (55 miles and 249 miles) high.
By the way, for all the amateur astronomy photographers, there’s a potential chance for you to get involved with future research activities.
“Commercially available GPS units for digital SLR cameras have become popular and relatively inexpensive, and it is easy and very useful for photographers to record the accurate time and position in photographic files,” said Kataoka. “I am thinking of developing a website with a submission system to collect many interesting photographs from night-sky photographers over the world via the Internet.”
From the Cat’s Eye to the Eskimo, planetary nebulae are arguably among the most dazzling objects in the Universe. These misnamed stellar remnants are created when the outer layers of a dying star blows off and expands into space. However, they can look radically different from one another, revealing complicated histories and structures.
But recently, astronomers have argued that some of the most exotic shapes are the result of not one, but two stars at the center. It is the interaction between the progenitor star and a binary companion that shapes the resulting planetary nebula.
The archetypal planetary nebula is spherical. Most planetary nebulae, however, have been shown to be non-spherical, complex structures.
“LoTr 1 is one such planetary nebula, but with a twist,” Amy Tyndall – a graduate student at the University of Manchester and lead author on the study – told Universe Today. It has not one star at its center but two. The binary central star system consists of a faint, hot white dwarf and a cool companion – a rapidly rotating giant.
LoTr 1 with a binary central star system and two slightly elongated shells, with ages of 17 and 35 thousand years. Credit: Tyndal et al.
LoTr 1 was first discovered by astronomers using the 1.2 meter telescope at the Royal Observatory in Edinburgh, Scotland. At the time it seemed that LoTr 1 was similar to a particular group of 4 planetary nebulae (Abell 35, Abell 70, WeBo 1 and LoTr 5), all of which had a central binary star system.
Another common factor amongst this particular group is that in most cases the companion star seemed to be a barium star – a cool giant that shows relatively large amounts of barium. Before the planetary nebula forms, the progenitor star dredges up an excess amount of Barium on its surface. It then releases a Barium-enriched stellar wind, which falls on its companion star.
“After the stellar envelope is ejected to form the surrounding nebula, the giant star evolves into a white dwarf, while the contaminated star retains the barium from the wind as it continues to evolve to form a Barium star,” explains Tyndall.
Tyndall and her collaborates set out to see if the companion star within LoTr 1 was in fact a Barium star. They acquired data from telescopes in both Chile and Australia and compared their results to the two other elusive planetary nebulae in the group: Abell 70 and WeBo 1.
“If barium is indeed present, it would be a good step further towards our understanding of how mass is transferred between stars in a binary system, and how that subsequently affects the formation and morphology of planetary nebulae,” says Tyndall.
While the results show that LoTr 1 does consist of binary star system, the companion star is not a Barium star. But a null result is still a result. “LoTr 1 remains an interesting object to us as it shows that we still have huge gaps in our knowledge as to how these stunning objects form,” Tyndall told Universe Today.
Without the presence of Barium, it would appear at first that little mass was transferred to the companion star. However, the companion star is rotating rapidly, which is a direct consequence of mass transfer. The most plausible explanation is that the mass was transferred before the barium could be dredged up to the stellar surface.
If the stellar evolution was cut short this way then there will be detectable evidence in the properties of the white dwarf. The next step will be to take another look at this odd planetary nebula in hopes of better understanding the complexities of this system.
The paper has been accepted for publication in the Monthly Notices of the Royal Astronomical Society and is available for download here.
Artist's conception of the Mars 2020 rover. Credit: NASA
As Day 2 of the United States government shutdown continues, some short-term effects are already in evidence when it comes to Earth and space.
Most of the NASA and National Oceanic and Atmospheric Administration (NOAA) websites are offline. Social media updates are silent. At NASA, 97% of agency employees are off work and media reports indicate that 55% of NOAA’s employees are furloughed.
If the shutdown lasts for very long, however, long-term programs could feel the pain. This includes a couple of Mars missions NASA is developing, as well as Earth-based climate research and satellite observation from NOAA.
Mars 2020
A twin rover to Mars Curiosity, called Mars 2020 for now, is expected to leave for the Red Planet in 2020 and do investigations into past life and habitability. Planning is still in the early stages, but an announcement of opportunity for science investigators was supposed to happen on Oct. 8. Notices of intent were due Oct. 15.
“The preproposal conference, scheduled for 10/8, may be rescheduled and the due date for NOIs (currently 10/15) could be delayed, if the government is still shut down closer to those dates,” NASA officials wrote in an update before the shutdown on Monday.
MAVEN team members, including chief scientist Bruce Jakosky (2nd from left) pose with spacecraft inside the cleanroom at the Kennedy Space Center on Sept. 27, 2013. Credit: Ken Kremer/kenkremer.com
MAVEN
As widely reported yesterday, the next Mars orbiter from NASA is expected to lift off from Earth on Nov. 18. Now, however, preparatory work has ceased and there is some concern from team members that it will miss the launch window, which extends into December. At worst, this means MAVEN’s launch could be delayed until 2016, when the next opportunity opens.
“The hardware is being safed, meaning that it will be put into a known, stable, and safe state,” Bruce Jakosky, MAVEN’s principal investigator, told Universe Today‘s Ken Kremer yesterday. “We’ll turn back on when told that we can. We have some margin days built into our schedule.”
NOAA
As with NASA, NOAA is keeping up with mission-critical activities — which in their case, includes weather forecasting. Long-term climate research, however, is reportedly being shelved.
“For example, Harold Brooks, a top tornado researcher who works at the National Severe Storms Laboratory in Norman, Okla., reported his furlough notice on Facebook on Tuesday,” Climate Central wrote on Oct. 1. “Much of the staff at NOAA’s Earth Systems Research Lab and the Geophysical Fluid Dynamics Laboratory, except for positions related to maintaining computing resources, have also been furloughed. Those two labs are heavily involved in NOAA’s climate research programs.”
A view of Hurricane Irene taken by the GOES satellite at 2:55 p.m. Eastern Daylight Time on August 24, 2011. Credit: NASA
Observers are also worried that a lengthy shutdown could push back the time when new weather satellites become available. There have been multiple reports about a “weather satellite gap” coming in the United States as many of NOAA’s geostationary and polar-orbiting satellites are nearing the end of their expected lives. The Subcommittees on Oversight and Environment held hearings into this issue in September.
What’s still online?
These are some of the programs that are still happening at NASA and NOAA:
NASA’s Curiosity rover reaches out in ‘handshake’ like gesture with dramatic scenery of Mount Sharp in the background. This mosaic of images was snapped by Curiosity on Sol 262 (May 2, 2013) and shows her flexing the robotic arm. Two drill holes are visible on the surface bedrock below the robotic arm’s turret. Credit: NASA/JPL-Caltech/Ken Kremer-(kenkremer.com)/Marco Di Lorenzo
NASA:
Bare-bones management on programs such as the International Space Station and several robotic missions that are already in operation (such as the Lunar Atmosphere and Dust Environment Explorer (LADEE).
Certain missions are in critical phases that could be hurt if work stops, such as the James Webb Space Telescope, which is undergoing cryogenic testing on some of its instruments.
Several missions run out of the Jet Propulsion Laboratory and Applied Physics Laboratory are still running as usual, according to the Planetary Society, as these receive contract money from NASA; this means Mars Curiosity is still working, for example.
The Mars Reconnaissance Orbiter’s HiRISE camera is still snapping pictures, its Twitter account reported, which is positive given that it was intended to snap shots of Comet ISON during its closest approach to Mars yesterday.
The decades-long Landsat Earth observation program is still operating, according to The Atlantic, with data being sent back to Earth as usual. The difference is this information won’t be packaged as usual until government operations restart.
NOAA (all information according to this Department of Commerce document):
The Office of Oceanic and Atmospheric Research will keep 73 employees on board “to ensure continuity of crucial long-term historical climate records, and real-time regular research to support ongoing weather and air quality prediction services,” NOAA said.
184 employees will stay with the Environmental Satellite and Data Information Service for command and control of several satellites for NOAA and the Department of Defense.
474 employees will remain with the National Marine Fisheries Service. 174 are funded in another form besides appropriations. The others are a mix of law enforcement, fisheries management and property protection officials.
490 employees are with the Office of Marine and Aviation Operations for observational data collection related to weather forecasting.
173 employees are with the National Ocean Service. 17 are funded outside of appropriations, while the 156 remaining “are required to protect against imminent and significant threats to life and property by supporting safe maritime commerce in U.S. waters, including real-time water level data for ships entering U.S. ports, critical nautical chart updates, and accurate position information,” NOAA stated. Some are also monitoring marine health aspects such as algal blooms.
There are 19 IT-related employees and 20 employees providing support services.
The large bulk of employees still at work, 3,935 people, are with the National Weather Service to keep up weather forecasting.
There’s no word yet on when government employees could go back to work. Congress representatives are jousting over the implementation of a spending bill to keep the money flowing to government departments. One big issue: whether to include the Affordable Care Act, sometimes dubbed Obamacare, in the bill.
Another deadline is looming, too. Treasury Secretary Jack Lew has warned repeatedly that on Oct. 17, if the debt ceiling is not raised, the United States government may default on some financial obligations.
At around 10 p.m. last night, the northern sky was alive with colorful auroral patches and arcs. Details: 15mm lens at f/2.8, ISO 800 and 25 second exposure. Credit: Bob King
I’m writing this at 1:30 a.m. running on what’s powering the sky over northern Minnesota right now – auroral energy. Even at this hour, rays are still sprouting in the southern sky and the entire north is milky blue-white with aurora borealis. Frankly, it’s almost impossible to resist going out again for another look.
Now updated with additional images.
An erupting filament and sharp, southward dip in the interplanetary magnetic field (IMF) was responsible for last night’s northern lights show. This image was taken with the Solar and Heliospheric Observatory’s sun-blocking coronagraph on Sept. 30. Credit: NASA/ESA
The arrival of a powerful solar wind in excess of 375 miles per second (600 km/second) from a coronal mass ejection shocked the Earth’s magnetic sheath last night beginning around 9 p.m. CDT. The sun’s magnetic field, embedded in the wind, pointed sharply southward, allowing eager electrons and protons to worm their way past our magnetic defenses and excite the atoms in the upper atmosphere to glow. Voila! Northern lights.
A classic quiet start to Tuesday night’s northern lights – a low green arc below the Big Dipper topped by a very faint red border. Credit: Bob King
Sure, it started innocently enough. A little glow low in the northern sky. But within half an hour the aurora had intensified into a dense bar of light so and green and bright it cast shadows. This bar or swath grew and grew like some atomic amoeba until it swelled beyond the zenith into the southern sky. Meanwhile, an isolated patch of aurora glowed like an green ember beneath the Pleiades in the northeastern sky. The camera captured its eerie appearance as well as spectacular curtains of red aurora dancing above the dipper-shaped cluster.
A single patch of aurora glows beneath the Pleiades star cluster at center. Beautiful red rays as seen in the time exposure were only faintly visible with the naked eye. Credit: Bob King
Soft patches, oval glows and multiple arcs lit up the north, east and west, but in the first two hours of the display I never saw a ray or feature with any definition. The camera recorded a few but all was diffuse and pillowy to the eye. Rays finally made their appearance later – after midnight and later – when they massed and surged to the zenith and beyond.
Looks a little scary. A thick wall of green aurora surges upward in the northern sky headed for the zenith. Credit: Bob King
Then came the flickering, flame-like patches and snaky shapes writhing lifelike across the constellation Pegasus during the phase called the coronal aurora. That’s when all the curtains and rays gather around the local magnetic zenith. As they flicker and flame, their shapes transform into eagle wings and snakes wriggling across the stars.
A large comet-like auroral form accented with red rays took up residence in the southeastern sky in Cetus from about 10:15 until 11 p.m. last night. around 10:30 p.m. Credit: Bob King
Funny, the space weather forecast called for quiet conditions last night and for the next two nights. But the eruption of a large filament, a tubelike region of dense hydrogen gas held aloft in the sun’s atmosphere by magnetic fields, sent a bundle of subatomic joy in Earth’s direction a bit earlier than expected. More auroras are possible tonight and tomorrow night as the effect of the shock wave continues. Despite the U.S. government shutdown, the Space Weather Prediction Center remains open.
There are so many ways to appreciate the aurora but my favorite is simply to stand there dumbfounded and try to take it all in. Few phenomena in nature are more deeply moving.
Opposite Cetus in the Aquila Milky Way, a huge ghostly patch resembling breath on a mirror lingered for some 20 minutes before fading away. Credit: Bob KingThis comet-like wisp next to Alpha Andromeda east of the Square of Pegasus appeared to flutter in the wind as it constantly dimmed, brightened and shape-shifted. Click photo to learn more about when to expect the next auroral display. Credit: Bob KingFinally – a mighty show of rays around 3 a.m. this morning. What you don’t see in the photo are the rhythmic pulsations fluttering through the entire display, a phenomenon known as “flaming”. Credit: Bob King
Magnetic and auroral activity indicators shot up to high levels last night and this morning. Left image from the POES satellite shows the extent of the auroral oval shortly after midnight CDT. At right, the Kp index shot up to 6 – a G2 or moderate geomagnetic storm – by the early morning. Click to see the current oval. Credit: NOAA
UPDATE: Other astrophotographers in the US also were able to capture some aurora images. John Chumack, whose images we frequently feature here on UT got this shot early on the morning of October 2:
Aurora Borealis, ‘The Northern Lights, as seen near Dayton, Ohio on October 2, 2013. Credit and copyright: John Chumack/Galactic Images.
And Alan Dyer in Canada got this amazing “fiery” shot:
A red and green aurora, from southern Alberta, Canada on Oct 1, 2013. Credit and copyright: Alan Dyer/Amazing Sky Photography.
This timelapse from Arthur, Ontario was shot on Oct. 2 as well:
Up for a challenge? Got a big 12” light bucket of a Dobsonian telescope and looking for something new to point it at? This week, as the Moon reaches New phase on October 4th and stays safely out of the late evening sky, why not check out Uranus and its retinue of moons. And yes, we’ve heard just about ALL the Uranus jokes —its pronouncedyer-in-us, thank you very much — but feel free to attempt to pen an original if you must.
Now, back to astronomy. Uranus reaches opposition for 2013 on Thursday, October 3rd at 14:00 Universal Time. Opposition is the point in time that an outer planet rises as the Sun sets. In the case of Uranus, its opposition dates advance forward by about 4-5 days each year.
The current location of Uranus in Pisces. Created by the author using Stellarium. (click to enlarge).
This also marks the start of the best time to hunt for the planet among the star fields of the constellation Pisces. Uranus will reach its maximum elevation above the southern horizon for northern hemisphere viewers for early October around local midnight. For observers south of the equator, Uranus will transit to the north. Incidentally, Uranus also currently sits near the equinoctial point occupied by the Sun during the March equinox, making viewing opportunities nearly equal for both hemispheres.
Uranus is 19.04 astronomical units distant during opposition 2013, or about 158 light minutes away. Shining at magnitude +5.8, Uranus presents a tiny blue-green disk just under 4” across at opposition.
Uranus currently lies six degrees SW of the +4.4 magnitude star Delta Piscium, on the border of the constellations Pisces and Cetus. Uranus will actually be crossing once again into the non-zodiacal constellation of Cetus later this year.
Discovered in 1781 by Sir William Herschel, Uranus has only completed 2 full orbits (2.75 to be precise) in its 84.3 year trips about the Sun. We can be thankful that William’s proposal to name the planet Geogium Sidus after his benefactor King George the III didn’t stick!
The path of Uranus into Cetus. Created by the author using Starry Night Education software.
At opposition, Uranus will be located at;
Right Ascension: 0h 40’
Declination: +3° 25’
Five of the 27 known moons of Uranus are also within the grasp of a moderate-sized backyard scope as well. The trick is to catch ‘em near greatest elongation, when they appear farthest from the “glare of Uranus” (hey, there’s a freebie for a snicker or two). An eyepiece equipped with an occulting bar, or simply nudging Uranus out of the field of view can also help.
With magnitudes ranging from +13 to +16, the moons of Uranus are similar in brightness to Neptune’s large moon Triton or the tiny world Pluto.
The five brightest moons of Uranus and their respective maximum elongations are:
Chart constructed by author.
And here’s a handy finder chart for the coming month, showing maximum elongations for each:
A corkscrew graph featuring the greatest elongations for the five brightest moons of Uranus through October. (Created by Ed Kotapish using PDS Rings Node).
The first two moons were named Titania and Oberon by William’s son John after characters from William Shakespeare’s A Mid-Summer Night’s Dream. William discovered the first two moons of Uranus on the night of January 11th, 1787 using his 49.5” reflector. His scopes were so advanced for his day, that it wasn’t until over a half a century later that William Lassell discovered Umbriel and Ariel using the Liverpool Observatory’s 24” reflector in 1851.
Gerard Kuiper would later add tiny Miranda to the list, nabbing it with the McDonald Observatory’s 82” Otto Struve Telescope in 1948. We would then have to wait until Voyager 2’s 1986 flyby of Uranus in 1986 to add more. To date, Voyager 2 remains the only spacecraft to visit Uranus and Neptune.
The current convention established by the International Astronomical Union is to name the moons of Uranus after characters from the plays of Shakespeare or Alexander Pope’s Rape of the Lock.
There’s still a wide range of names in said literature to choose from!
It’s interesting to note that the orbits of the moons of Uranus are also currently tipped open about 25 degrees to our line of sight and widening. They were edge on in December 2007, and will be perpendicular to our Earthly view come 2029, after which they’ll head back to edge on in 2049. This is because Uranus and the orbits of its moons are tipped at a 97 degree angle relative to the planet’s orbit. This is why elongations for its moons are often quoted it terms of “north and south” of the planet, rather than the familiar east and west. Shadow transits of the moons can occur with about a year and a half during plane-crossing seasons, but they’re ~42 years apart and tough to spot on the tiny disk of Uranus!
An example of the orientation of Uranus’s moons on October 4th, with Oberon at greatest elongation. Note that Miranda is the tiny unlabeled moon with the interior orbit. (Created by the author using Starry Night Education software).
Uranus also reached aphelion in 2009 at 20.099 AU from the Sun —we’re still at the farther end of the spectrum, as oppositions of Uranus can range from 19.09 to 17.28 AU distant.
Uranus will rise earlier on each successive evening until it reaches quadrature at the end of the year on December 30th. At this point, it’ll be roughly due south at local sunset. Keep in mind, there’s also another ice giant worth hunting for in the adjacent constellation of Aquarius named Neptune.
So ignore those bad puns, and be sure to take out that 10” (scope, that is) and point it at Uranus!
A quasar resides in the hub of the nearby galaxy NGC 4438. Credit: NASA/ESA, Jeffrey Kenney (Yale University), Elizabeth Yale (Yale University)
50 million light-years away a quasar resides in the hub of galaxy NGC 4438, an incredibly bright source of light and radiation that’s the result of a supermassive black hole actively feeding on nearby gas and dust (and pretty much anything else that ventures too closely.) Shining with the energy of 1,000 Milky Ways, this quasar — and others like it — are the brightest objects in the visible Universe… so bright, in fact, that they are used as beacons for interplanetary navigation by various exploration spacecraft.
“I must go down to the seas again, to the lonely sea and the sky,
And all I ask is a tall ship and a star to steer her by.”
Deep-space missions require precise navigation, especially when approaching bodies such as Mars, Venus, or comets. It’s often necessary to pinpoint a spacecraft traveling 100 million km from Earth to within just 1 km. To achieve this level of accuracy, experts use quasars – the most luminous objects known in the Universe – as beacons in a technique known as Delta-Differential One-Way Ranging, or delta-DOR.
How delta-DOR works (ESA)
Delta-DOR uses two antennas in distant locations on Earth (such as Goldstone in California and Canberra in Australia) to simultaneously track a transmitting spacecraft in order to measure the time difference (delay) between signals arriving at the two stations.
Unfortunately the delay can be affected by several sources of error, such as the radio waves traveling through the troposphere, ionosphere, and solar plasma, as well as clock instabilities at the ground stations.
Delta-DOR corrects these errors by tracking a quasar that is located near the spacecraft for calibration — usually within ten degrees. The chosen quasar’s direction is already known extremely well through astronomical measurements, typically to closer than 50 billionths of a degree (one nanoradian, or 0.208533 milliarcsecond). The delay time of the quasar is subtracted from that of the spacecraft’s, providing the delta-DOR measurement and allowing for amazingly high-precision navigation across long distances.
“Quasar locations define a reference system. They enable engineers to improve the precision of the measurements taken by ground stations and improve the accuracy of the direction to the spacecraft to an order of a millionth of a degree.”
– Frank Budnik, ESA flight dynamics expert
So even though the quasar in NGC 4438 is located 50 million light-years from Earth, it can help engineers position a spacecraft located 100 million kilometers away to an accuracy of several hundred meters. Now that’s a star to steer her by!
Artist's impression of how huge cosmic structures deflect photons in the cosmic microwave background (CMB). Credit: ESA and the Planck Collaboration
Leftover radiation from the Big Bang — that expansion that kick-started the universe — can be bent by huge cosmic structures, just like other light that we see in the universe. While the finding seems esoteric at first glance, scientists say the discovery could pave the way for finding a similar kind of signal that indicate the presence of gravitational waves in the moments after the universe was born.
That light is called the cosmic microwave background and is the radiation that was visible when the universe became transparent to radiation, 380,000 years after the Big Bang. A tiny bit of the CMB is polarized. There are two types of polarized light in the CMB: E-modes (first detected in 2002) and B-modes (which were just detected using a telescope in Antarctica and ESA’s Herschel space observatory.
“[B-modes] can arise in two ways,” the European Space Agency wrote in a press release.
“The first involves adding a twist to the light as it crosses the Universe and is deflected by galaxies and dark matter – a phenomenon known as gravitational lensing. The second has its roots buried deep in the mechanics of a very rapid phase of enormous expansion of the Universe, which cosmologists believe happened just a tiny fraction of a second after the Big Bang – ‘inflation’.”
More results are on the way from ESA’s Planck telescope in 2014, at which point scientists hope to see this B-mode of the second type. For now, check out the full study in Physical Review Letters. There is also a preprint version available on Arxiv.
