Afternoon on Mars (MSL Mastcam mosaic)(NASA/JPL-Caltech/MSSS. Edit by Jason Major)
Here’s a pretty picture for your Friday: a mosaic of Mastcam images acquired by Curiosity on mission Sol 582, also known to us Earthlings as Thursday, March 27, 2014. Barsoom sure looks lovely this time of year!
The mosaic was assembled from five raw images downlinked to the MSL site earlier today. I pasted them together in Photoshop, aligning the edge of one to the next using landscape objects as visual markers, and then did a little bad pixel cleanup (Mastcam has a notorious black smudge a few pixels wide just off-center) and then cropped the result, with a bit of surface cloning at the lower right to fill in some missing Martian soil. The I hit it with an HDR filter, which I’m usually not a fan of but in in this instance it turned out pretty nice.
Two videos recently released by the Hubble team take us on a tour of two famous and intriguing cosmic objects: the stellar wind-blown “celestial snow angel” Sharpless 2-106 and the uncannily equine Horsehead Nebula, imaged in infrared wavelengths by the HST.
Using Hubble imagery complemented with data from the Subaru Infrared Telescope and ESO’s Visible and Infrared Survey Telescope for Astronomy — VISTA, for short — the videos show us an approximation of the three-dimensional structures of these objects relative to the stars surrounding them, providing a perspective otherwise impossible from our viewpoint on Earth.
Artist's concept of a hot Jupiter exoplanet orbiting a star similar to tau Boötes (Image used with permission of David Aguilar, Harvard-Smithsonian Center for Astrophysics)
As more and more exoplanets are identified and confirmed by various observational methods, the still-elusive “holy grail” is the discovery of a truly Earthlike world… one of the hallmarks of which is the presence of liquid water. And while it’s true that water has been identified in the thick atmospheres of “hot Jupiter” exoplanets before, a new technique has now been used to spot its spectral signature in yet another giant world outside our solar system — potentially paving the way for even more such discoveries.
Researchers from Caltech, Penn State University, the Naval Research Laboratory, the University of Arizona, and the Harvard-Smithsonian Center for Astrophysics have teamed up in an NSF-funded project to develop a new way to identify the presence of water in exoplanet atmospheres.
Previous methods relied on specific instances such as when the exoplanets — at this point all “hot Jupiters,” gaseous planets that orbit closely to their host stars — were in the process of transiting their stars as viewed from Earth.
This, unfortunately, is not the case for many extrasolar planets… especially ones that were not (or will not be) discovered by the transiting method used by observatories like Kepler.
So the researchers turned to another method of detecting exoplanets: radial velocity, or RV. This technique uses visible light to watch the motion of a star for the ever-so-slight wobble created by the gravitational “tug” of an orbiting planet. Doppler shifts in the star’s light indicate motion one way or another, similar to how the Doppler effect raises and lowers the pitch of a car’s horn as it passes by.
The two Keck 10-meter domes atop Mauna Kea. (Rick Peterson/WMKO)
But instead of using visible wavelengths, the team dove into the infrared spectrum and, using the Near Infrared Echelle Spectrograph (NIRSPEC) at the W. M. Keck Observatory in Hawaii, determined the orbit of the relatively nearby hot Jupiter tau Boötis b… and in the process used its spectroscopy to identify water molecules in its sky.
“The information we get from the spectrograph is like listening to an orchestra performance; you hear all of the music together, but if you listen carefully, you can pick out a trumpet or a violin or a cello, and you know that those instruments are present,” said Alexandra Lockwood, graduate student at Caltech and first author of the study. “With the telescope, you see all of the light together, but the spectrograph allows you to pick out different pieces; like this wavelength of light means that there is sodium, or this one means that there’s water.”
Previous observations of tau Boötis b with the VLT in Chile had identified carbon monoxide as well as cooler high-altitude temperatures in its atmosphere.
Now, with this proven IR RV technique, the atmospheres of exoplanets that don’t happen to cross in front of their stars from our point of view can also be scrutinized for the presence of water, as well as other interesting compounds.
“We now are applying our effective new infrared technique to several other non-transiting planets orbiting stars near the Sun,” said Chad Bender, a research associate in the Penn State Department of Astronomy and Astrophysics and a co-author of the paper. “These planets are much closer to us than the nearest transiting planets, but largely have been ignored by astronomers because directly measuring their atmospheres with previously existing techniques was difficult or impossible.”
Once the next generation of high-powered telescopes are up and running — like the James Webb Space Telescope, slated to launch in 2018 — even smaller and more distant exoplanets can be observed with the IR method… perhaps helping to make the groundbreaking discovery of a planet like ours.
“While the current state of the technique cannot detect earthlike planets around stars like the Sun, with Keck it should soon be possible to study the atmospheres of the so-called ‘super-Earth’ planets being discovered around nearby low-mass stars, many of which do not transit,” said Caltech professor of cosmochemistry and planetary sciences Geoffrey Blake. “Future telescopes such as the James Webb Space Telescope and the Thirty Meter Telescope (TMT) will enable us to examine much cooler planets that are more distant from their host stars and where liquid water is more likely to exist.”
The findings are described in a paper published in the February 24, 2014 online version of The Astrophysical Journal Letters.
ESA's Gaia spacecraft as seen by the VLT (Credit: ESO)
Gaia, ESA’s long-anticipated mission to map the stars of our galaxy (as well as do a slew of other cool science things) is now tucked comfortably in its position in orbit around Earth-Moon L2, a gravitationally stable spot in space 1.5 million km (932,000 miles) away.
Once its mission begins in earnest, Gaia will watch about a billion stars an average of 70 times each over a five-year span… that’s 40 million observations every day. It will measure the position and key physical properties of each star, including its brightness, temperature and chemical composition, and help astronomers create the most detailed 3D map of the Milky Way ever.
But before Gaia can do this, its own position must be precisely determined. And so several of the world’s most high-powered telescopes are trained on Gaia, keeping track daily of exactly where it is up to an accuracy of 150 meters… which, with the ten-meter-wide spacecraft one and a half million kilometers away, isn’t too shabby.
Called GBOT, for Ground Based Orbit Tracking, the campaign to monitor Gaia’s position was first set up in 2008 — long before the mission launched. This allowed participating observatories to practice targeting on other existing spacecraft, like NASA’s WMAP and ESA’s Planck space telescopes.
The image above shows an image of Gaia (circled) as seen by the European Southern Observatory’s Very Large Telescope Survey Telescope (VST) atop Cerro Paranal in Chile, one of the supporting observatories in the GBOT campaign. The images were taken with the 2.6-meter Survey Telescope’s 268-megapixel OmegaCAM on Jan. 23, 6.5 minutes apart. With just the reflected sunlight off its circular sunshield, the distant spacecraft is about a million times fainter than what your eyes could see unaided.
Gaia mapping the stars of the Milky Way. (ESA/ATG medialab; background: ESO/S. Brunier)
It’s also one the closest objects ever imaged by the VST.
Currently Gaia is still undergoing calibration for its survey mission. Some problems have been encountered with stray sunlight reaching its detectors, and this may be due to the angle of the sunshield being a few degrees too high relative to the Sun. It could take a few weeks to implement an orientation correction; read more on the Gaia blog here.
Of the billion stars Gaia will observe, 99% have never had their distances accurately measured. Gaia will also observe 500,000 distant quasars, search for brown dwarfs and exoplanets, and will conduct experiments testing Einstein’s General Theory of Relativity. Find out more facts about the mission here.
Gaia launched on December 19, 2013, aboard a Soyuz VS06 from ESA’s spaceport in Kourou, French Guiana. Watch the launch here.
Shepherd moon Prometheus hovers just inside the reflective F ring
Lit by eerie, reflected light from Saturn’s F ring (and a casting a faint shadow through a haze of icy “mist”) Saturn’s moon Prometheus can be seen in the raw image above, captured by Cassini’s narrow-angle camera on Feb. 5 from a distance of 667,596 miles (1,074,392 km). It’s also receiving some light reflected off Saturn, which is off frame at the top (where the outermost edge of the A ring and the Keeler gap can be seen.)
As the potato-shaped Prometheus approaches the ring it yanks fine, icy material in towards itself, temporarily stretching the bright particles into long streamers and gaps and even kicking up bright clumps in the ring. It’s a visual demonstration of gravity at work! Watch an animation of this below, made from images acquired just before and after the one above:
Streamers and clumps created by the passing Prometheus on Feb. 5, 2014. (NASA/JPL/SSI. Animation by Jason Major.)
At its longest Prometheus is about 92 miles (148 km) across, but only 42 miles (68 km) in width. It circles Saturn in a wave-shaped, scalloping orbit once every 14.7 hours.
Expedition 38 Soyuz Commander Mikhail Tyurin, holding the Olympic torch, and Flight Engineers Koichi Wakata and Rick Mastracchio wave farewell prior to boarding the Soyuz TMA-11M rocket for launch. (NASA/Bill Ingalls)
Ever since the first relay for the 1936 summer Olympic games in Berlin, Olympic torches have traditionally been used to carry a burning flame — symbolically and physically — from Greece to the host country’s stadium. These journeys, undertaken by privileged individuals and athletes from around the world, span months and many thousands of miles… but this year, the fire illuminating the 2014 Winter Olympics in Sochi, Russia will be ignited with a torch that has truly traveled around the globe — many times, in fact.
On Nov. 6, 2013 (Nov. 7 UT) a Soyuz TMA-11M rocket launched from Baikonur Cosmodrome in Kazakhstan ferrying the Expedition 38/39 crew to the ISS. Along with their mission supplies and personal items, the crew members brought along something special: a torch for the 2014 Olympics.
The torch was brought into space two days later by Expedition 38 crew members Oleg Kotov and Sergei Ryazanskiy during an EVA on Nov. 9, and handed off from one cosmonaut to the other in a symbolic relay in orbit, the first to be carried out 265 miles above the planet traveling 17,500 mph. (Watch a video of the EVA below.)
The Olympic torch in orbit during an EVA on Nov. 9, 2013
I say “symbolic” because the torch was not lit during its time aboard the ISS or, obviously, while in space. (Open flames are highly frowned upon aboard Station!) Still, it was the first time in history an Olympic torch, a symbol of peace, human achievement, and international cooperation, has been brought aboard the Space Station — which itself represents the same noble values.
Considering the ISS travels around the Earth 16 times each day, and the torch spent nearly four days in space, that’s one well-traveled fire bearer!
The spacefaring torch was carried back to Earth with Expedition 37 crew members Karen Nyberg of NASA, Fyodor Yurchikhin of the Russian Federal Space Agency, and Luca Parmitano of the European Space Agency on Sunday, Nov. 10. And while the actual Olympic flame had continued to be carried by torchbearers across more than 40,000 miles through 2,900 towns and villages in Russia, it will be that particular spacefaring torch that will be used to light the 2014 Olympic cauldron during the Opening Ceremony in Sochi on Feb. 7.
“As the torch is used to light the Olympic flame in Sochi, and symbolizes harmony and goodwill throughout the games, the space station will remain one of the brightest objects in the night sky, a beacon of international cooperation and research providing tangible benefits for all humanity.” (NASA)
Read more in a recent NASA news article here, and learn more about the 2014 Sochi Olympic torch here.
Saturn makes a beautifully striped ornament in this natural-color image, showing its north polar hexagon and central vortex (Credit: NASA/JPL-Caltech/Space Science Institute)
Cassini couldn’t make it to the mall this year to do any Christmas shopping but that’s ok: we’re all getting something even better in our stockings than anything store-bought! To celebrate the holiday season the Cassini team has shared some truly incredible images of Saturn and some of its many moons for the world to “ooh” and “ahh” over. So stoke the fire, pour yourself a glass of egg nog, sit back and marvel at some sights from a wintry wonderland 900 million miles away…
Thanks, Cassini… these are just what I’ve always wanted! (How’d you know?)
Saturn’s southern hemisphere is growing more and more blue as winter approaches there — a coloration similar to what was once seen in the north when Cassini first arrived in 2004:
Saturn’s southern hemisphere images from a million miles away (Credit: NASA/JPL-Caltech/Space Science Institute)
(The small dark spot near the center right of the image above is the shadow of the shepherd moon Prometheus.)
Titan and Rhea, Saturn’s two largest moons, pose for Cassini:
Rhea (front) and Titan, images by Cassini in June 2011 (Credit: NASA/JPL-Caltech/Space Science Institute)
The two moons may look like they’re almost touching but in reality they were nearly half a million miles apart!
Titan’s northern “land of lakes” is visible in this image, captured by Cassini with a special spectral filter able to pierce through the moon’s thick haze:
Titan images by Cassini on Oct. 7, 2013 (Credit: NASA/JPL-Caltech/Space Science Institute)
The frozen, snowball-like surface of the 313-mile-wide moon Enceladus:
Enceladus: a highly-reflective and icy “snowball in space” (Credit: NASA/JPL-Caltech/Space Science Institute)
(Even though Enceladus is most famous for its icy geysers, first observed by Cassini in 2005, in these images they are not visible due to the lighting situations.)
Seen in a different illumination angle and in filters sensitive to UV, visible, and infrared light the many fractures and folds of Enceladus’ frozen surface become apparent:
View of the trailing face of Enceladus (Credit: NASA/JPL-Caltech/Space Science Institute)
Because of Cassini’s long-duration, multi-season stay in orbit around Saturn, researchers have been able to learn more about the ringed planet and its fascinating family of moons than ever before possible. Cassini is now going into its tenth year at Saturn and with much more research planned, we can only imagine what discoveries (and images!) are yet to come in the new year(s) ahead.
“Until Cassini arrived at Saturn, we didn’t know about the hydrocarbon lakes of Titan, the active drama of Enceladus’ jets, and the intricate patterns at Saturn’s poles,” said Linda Spilker, the Cassini project scientist at NASA’s Jet Propulsion Laboratory. “Spectacular images like these highlight that Cassini has given us the gift of knowledge, which we have been so excited to share with everyone.”
Is this really how the Solar System works? (Rendering by DjSadhu)
The short answer? No. Not in the way that a popular animated gif insinuates, at least.
If you’re even a casual space fan you may have seen a viral gif animation showing our solar system traveling through space, the motions of the planets tracing corkscrew “vortex” paths around a line-driving Sun. While it’s definitely intriguing to watch (in that mesmerizingly-repetitive gif fashion) and rendered with a talented flair for design, there are two fundamental problems with it. One: it’s not entirely correct, scientifically, and two: its creator’s intention is to illustrate a decidedly un-scientific point of view about the Solar System and the Universe as a whole.
For the long answer, I now offer up the stage to astrophysicist Rhys Taylor, who recently posted an in-depth article describing why the planets do yet move… just not like that.
There’s this annoying space GIF roaming the internet causing trouble. Perhaps you’ve seen it. No ? Well, here it is.
Solar system “vortex” gif (by DjSadhu)
What it purports to show is the motion of the Solar System through space. But the accuracy of this has been utterly derided as an affront to scientific dignity. Which is a shame, because the video version is really quite nicely done, with good camera movement and a catchy soundtrack. The principle antagonist is notorious “Bad Astronomer” Phil Plait, who wrote a convincing and virulent attack on the video. I decided to investigate for myself.
Like many people, I was at first glance really quite impressed with the video, and didn’t have any major objections to it. Obviously the orbits and size of the planets are not to scale (and I think their orbital speeds have be altered too), but that’s just to make them visible. Fair enough. But then I read Phil Plait’s analysis, and it seems that things are much, much worse than that. Says Plait :
“Sadhu shows the Sun leading the planets, ahead of them as it goes around the galaxy… This is not just misleading, it’s completely wrong.”
He clarifies :
“Sometimes the planets really are ahead of the Sun as we orbit in the Milky Way, and sometimes trail behind it (depending on where they are in their orbit around the Sun).” [my italics]
The orbits of the major planets of the solar system all lie in a narrow plane (like being in economy class! hahaha… sorry), which is tilted at about 60 degrees to the disc of stars that forms the Milky Way. Like this:
We’ll return to the tilt in a moment. But first, if the Sun was really leading the planets, then the thing is completely ludicrous (and this is quite a major part of Plait’s argument). Yet I’m not so sure the viral gif does show the Sun leading the planets. Having read through the author’s website, I can’t find any evidence that he suggests this. In fact, some of other videos on his website clearly show that this isn’t the case:
It seems to me that the appearance of the Sun leading the planets in the gif is just the result of a projection effect – i.e. that things can look different from different angles. On the other hand, Plait read the source material for Sadhu’s model, so maybe there’s something in there that’s more explicit. I’ve glanced at it, but couldn’t find anything stating this precisely. Actually I couldn’t find a whole lot that was even vaguely coherent, but we’ll return to this later. For now, just keep in mind that Sadhu is using an alternative model, even though that may not always be evident.
What the gif definitely does not show is the fact that the orbits of the planets are tilted at about 60 degrees to the direction of the Sun’s motion. Says Plait :
“In the helical model, he shows the planets as orbiting around the Sun perpendicular to the motion of the Sun around the galaxy; “face-on”, if you like.This is wrong. Because the orbits of the planets are tipped by 60°, not 90°, they can sometimes be ahead and sometimes behind the Sun. That right there, and all by itself, shows this helical depiction is incorrect.”
There can be no mistaking that Sadhu’s video shows the orbits with the wrong tilt. But is that so critical? Well actually no, not really. Fact is that if you include the tilt, you still see the planets making a “spiral” pattern (technically it’s a helix) as they move through space. The overall appearance just isn’t that massively different compared to a 90-degree tilt.
Solar system model by Rhys Taylor (Click to play)
So what’s the big deal? What does the author claim in this internet sensation that’s so outrageous? Well, not much. That particular video/gif are actually fairly inoffensive, to my mind. The most basic notion that the planets trace helical paths through space is perfectly correct. What honestly surprises me is that this is so incredibly popular on the internet. If you weren’t aware that the Sun orbits the center of the galaxy — which, since the planets orbit it, necessitates that they trace out helical paths — then the education system has seriously failed. But do not despair! This can be remedied very, very easily.
But we’re not done yet. There’s a sting in the tail, and it’s a big one. The gif doesn’t show it, but the video version ends with the worrying remarks that:
“Rotational motion and vortex motion are completely different things.”*
“Life spirals.” [Picture of leaves]
“Life is vortex, not just rotation.” [Picture of developing ferns, then a flower, the Milky Way, the DNA double helix, etc.]
“The Solar System is part of life. Think about this while racing through space.”
*Yes, they are. Plait notes: “They’re different in more than just name; they’re actually very different physical motions with different properties—you can get helical motion without the particles in it interacting, like in the solar system, but in a vortex the particles interact through drag and friction.” Basically, claiming that the Solar System is a vortex is simply wrong. Sadhu appears not to have checked the word “vortex” in a dictionary.
I could forgive even these rather hippyish sentiments, if they were no more than that. Alas, they’re symptomatic of a much larger problem. Plait’s merciless attack is full of sound and fury, but it’s also signifying something. Reading more of the author’s website, it turns out he is actively promoting quackery. It’s on a par with the excellent Space Mirror Mystery* (the idea that everything further away than about 150 million km is just a reflection in a giant mirror), but less funny.
*I was delighted to find that this website is back online. Seriously, read it. It’s epic.
From Sadhu’s website:
“In this diagram it seems the Solar System travel to the left. When the Earth is also traveling[sic] to the left (for half a year) it must go faster than the Sun. Then in the second half of the year, it travels in a ‘relative opposite direction’ so it must go slower than the Sun. Then, after completing one orbit, it must increase speed to overtake the Sun in half a year. And this would go for all the planets. Just like any point you draw on a frisbee will not have a constant speed, neither will any planet.”
Apparently he thinks this is a problem. Worryingly, it suggests that he didn’t show the 60-degree orbital tilt not for mere simplicity, but because he doesn’t believe it’s possible. Which — if true — is utter madness, pure and simple. There’s absolutely no reason the planetary speeds have to be constant as they move around the galaxy — the massive gravitational pull of the Sun is keeping them firmly in its orbit, regardless of how those orbits are inclined.
“Secondly, most planets are visible throughout the entire year. In a ‘flat’ model, every single planet would hide behind the Sun at least once a year. They don’t. Now the heliocentric model isn’t entirely flat, but mostly.”
Fine. The heliocentric model isn’t flat, which perfectly explains why planets aren’t eclipsed by the Sun once per year. What need to state this ? Is he really saying that this is a problem in a heliocentric model…? SERIOUSLY?
“Fact of the matter is that if the helical model is correct and our Solar System is a traveling[sic] vortex, it will change how we feel about our journey. For me personally the heliocentric model feels like a useless marry[sic]-go-round: after one year we are back to square one. The helical model feels much more like progress, growth, a journey through space in which we never ever come back to our starting point. We are NOT in a big marry[sic]-go-round. We are on a journey.”
Planets trace a helical path in space because our Solar System is orbiting the center of the galaxy. Big bloody deal. It’s that simple. You don’t need a wacky alternative model of the Solar System for this – it’s happening anyway! As for going on a journey though – well no, not really. Every other star is also orbiting the center of the galaxy, so no, we’re not actually getting anywhere relative to other star systems.
Then there are some pointless ravings about the Mayan calendar.
He also links the following video. Skip to about 2 minutes in:
This has the bizarre quote that :
“The planets do not come back on to their [own] path[s]. They don’t. If they did, we most likely would have the same set of information over and over and over… like a broken record. And we’d probably get bored. It would be like Groundhog Year.”
Then he links a video claiming that the Fibonacci sequence is the fingerprint of God.
None of which changes the fact that his first video/gif has only minor inaccuracies, but at this point I can’t help feeling that this was more by luck than judgement.
Then there’s his second video. This one is more objectively just plain wrong. He shows the Sun tracing out a corkscrew pattern as it orbits the galaxy, which makes no sense. The Sun simply goes around the center of the galaxy (and up and down a little bit) — nothing else. It’s not orbiting anything else at the same time. For it to trace a helix is just nonsense. He seems to have an almost unique case of helix madness.
What of the source material — the alternative model Sadhu uses? Garbage. Utter garbage. I find it difficult to read more than a sentence or two, because it’s verging on incomprehensible. As in almost at the level of TimeCube.
“Three types of time may be recognized: – An absolute time that is universal and has neither a known starting point nor an end point; not even limited to a measurable parameter. – For living organisms there is a time for birth and a moment for death. The interval is the life span. This time may be measured with parameters like seconds, minutes, days and so on. Mechanical devices may measure fractions and to some extant reliable. In every case some kind of energy source or gear system is involved. -–When one is engaged with some work involvement in another activity may be impossible or result to be unnatural. In such cases personal values decide what course to take up and say “no time” to the other work, however important that may be. This time is highly subjective.”
Later: “The constellations at the background are sufficient evidence to deny the heliocentric orbits for planets. The Sun at 500 light seconds distance, when visible within a cone of 30° maintaining a background of one constellation, say for example Aries, (Hamel at 68ly) the SOLSTICES and EQUINOXES through Zodiac Earth maintains in the opposite constellation at midnight, namely Libra. After six months to maintain heliocentric orbit, the mid day of today should become midnight and the midnight should become midday. This has not taken place!“
Well of course it hasn’t — it’s complete gibberish ! Plait may well be right that somewhere in this mess is a model wherein the Sun leads the planets, but I don’t have the time or sheer mental fortitude to read the whole thing. I will note, though, that there’s a paragraph where the author rubbishes the conventional explanation for the ozone hole — and God help us all if that goes viral. That, not petty disputes about whether the orbits of planets are tilted by 60 or 90 degrees, is why such quackery deserves to be shot down without mercy.
“My feeling is that if your take-home message was only that the Solar System moves through space, and the planets trace out pretty spirally paths, then all is well and no harm done. But if it’s leading you to question the heliocentric model, then we’re all buggered.”
–Rhys Taylor, astrophysicist
In conclusion then, the first video and gif of the Solar System as a “vortex” are not really all that bad. Unfortunately, the inaccuracies are not due to some minor over-simplifications, but are symptoms of a some very deep-seated misunderstandings. My feeling is that if your take-home message was only that the Solar System moves through space, and the planets trace out pretty spirally paths, then all is well and no harm done. But if it’s leading you to question the heliocentric model, then we’re all buggered.
___________________
Thanks to Rhys Taylor for the guest post of his entertaining and informative article — at the very least, you got to watch “The Galaxy Song” again! Read more from Rhys (and check out some really nice infographics too) on his blog here.
Hubble image of variable star RS Puppis (NASA, ESA, and the Hubble Heritage Team)
6,500 light-years away in the southern constellation Puppis an enormous star pulses with light and energy, going through the first throes of its death spasms as it depletes its last reserves of hydrogen necessary to maintain a stable, steady radiance. This star, a Cepheid variable named RS Puppis, brightens and dims over a 40-day-long cycle, and newly-released observations with Hubble reveal not only the star but also the echoes of its bright surges as they reflect off the dusty nebula surrounding it.
The image above shows RS Puppis shining brilliantly at the center of its dusty cocoon. (Click the image for a super high-res version.) But wait, there’s more: a video has been made of the variable star’s outbursts as well, and it’s simply mesmerizing. Check it out below:
Assembled from observations made over the course of five weeks in 2010, the video shows RS Puppis pulsing with light, outbursts that are then reflected off the structure of its surrounding nebula. What look like expanding waves of gas are really “light echoes,” radiation striking the densest rings of reflective dust located at farther and farther distances from the star.
According to the NASA image description:
RS Puppis rhythmically brightens and dims over a six-week cycle. It is one of the most luminous in the class of so-called Cepheid variable stars. Its average intrinsic brightness is 15,000 times greater than our sun’s luminosity.
The nebula flickers in brightness as pulses of light from the Cepheid propagate outwards. Hubble took a series of photos of light flashes rippling across the nebula in a phenomenon known as a “light echo.” Even though light travels through space fast enough to span the gap between Earth and the moon in a little over a second, the nebula is so large that reflected light can actually be photographed traversing the nebula. (Source)
RS Puppis is ten times more massive than our Sun, and 200 times larger.
Cepheid variables are more than just fascinating cosmic objects. Their uncanny regularity in brightness allows astronomers to use them as standard candles for measuring distances within our galaxy as well as others — which is trickier than it sounds. Because of its predictable variation along with the echoing light from its surrounding nebula, the distance to RS Puppis (6,500 ly +/- 90) has been able to be calculated pretty accurately, making it an important calibration tool for other such stars. (Read more here.)
Full image credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)-Hubble/Europe Collaboration. Acknowledgment: H. Bond (STScI and Penn State University)
Christopher Nolan, the writer and director of Memento, Inception, and the most recent Batman films, is taking up space on the big screen next year — literally. Nolan’s newest film, Interstellar, will be a space exploration adventure featuring Matthew McConaughey, Jessica Chastain, Anne Hathaway, and Michael Caine (of course) and, based on this teaser trailer, maintains a reverent awareness of the iconic missions of the Space Age.
