A graphic designer in Rhode Island, Jason writes about space exploration on his blog Lights In The Dark, Discovery News, and, of course, here on Universe Today. Ad astra!
I love science fiction films and I especially love it when the “science” part leans closer to fact than fiction. (Yes, I’m looking at you, Europa Report.) Now I’ve never seen an actual catastrophe in orbit (and I hope I never do) but I have to assume it’d look a whole lot like what’s happening in the upcoming film “Gravity,” opening in U.S. theaters on October 4. This full official trailer was released today.
A disaster film sure becomes a whole lot more interesting when everything is moving 18,000 miles an hour and there’s no up or down. And, of course, space. (!!!)
Illustration of the Kepler spacecraft. Kepler's mission is over, but all of the exoplanets it found still need to be confirmed in follow-up observations. (NASA/Kepler mission/Wendy Stenzel)
Kepler may not be hanging up its planet-hunting hat just yet. Even though two of its four reaction wheels — which are crucial to long-duration observations of distant stars — are no longer operating, it could still be able to seek out potentially-habitable exoplanets around smaller stars. In fact, in its new 2-wheel mode, Kepler might actually open up a whole new territory of exoplanet exploration looking for Earth-sized worlds orbiting white dwarfs.
An international team of scientists, led by Mukremin Kilic of the University of Oklahoma’s Department of Physics and Astronomy, are suggesting that NASA’s Kepler spacecraft should turn its gaze toward dim white dwarfs, rather than the brighter main-sequence stars it was previously observing.
“A large fraction of white dwarfs (WDs) may host planets in their habitable zones. These planets may provide our best chance to detect bio-markers on a transiting ex- oplanet, thanks to the diminished contrast ratio between the Earth-sized WD and its Earth-sized planets. The James Webb Space Telescope is capable of obtaining the first spectroscopic measurements of such planets, yet there are no known planets around WDs. Here we propose to take advantage of the unique capability of the Kepler space- craft in the 2-Wheels mode to perform a transit survey that is capable of identifying the first planets in the habitable zone of a WD.”
– Kilic et al.
Any bio-markers — such as molecular oxygen, O2 — could later be identified around such Earth-sized exoplanets by the JWST, they propose.
Will Kepler be able to find the first Earth-sized exoplanet — or even an exomoon — orbiting a white dwarf? (Illustration of Kepler 22b. Credit: NASA/Ames/JPL-Caltech)
Because Kepler’s precision has been greatly reduced by the failure of a second reaction wheel earlier this year, it cannot accurately aim at large stars for the long periods of time required to identify the minute dips in brightness caused by the silhouetted specks of passing planets. But since white dwarfs — the dim remains of stars like our Sun — are much smaller, any eclipsing exoplanets would make a much more pronounced effect on their apparent luminosity.
In effect, exoplanets ranging from Earth- to Jupiter-size orbiting white dwarfs as close as .03 AU — well within their habitable zones — would significantly block their light, making Kepler’s diminished aim not so much of an issue.
“Given the eclipse signature of Earth-size and larger planets around WDs, the systematic errors due to the pointing problems is not the limiting factor for WDHZ observations,” the team assures in their paper “Habitable Planets Around White Dwarfs: an Alternate Mission for the Kepler Spacecraft.”
Even smaller orbiting objects could potentially be spotted in this fashion, they add… perhaps even as small as the Moon.
The team is proposing a 200-day-long survey of 10,000 known white dwarfs within the Sloan Digital Sky Survey (SDSS) area, and expects to find up to 100 exoplanet candidates as well as other “eclipsing short period stellar and sub-stellar companions.”
“If the history of exoplanet science has taught us anything, it is that planets are ubiquitous and they exist in the most unusual places, including very close to their host stars and even around pulsars… Currently there are no known planets around WDs, but we have never looked at a sufficient number of WDs at high cadence to find them through transit observations.”
NASA’s Ames Research Center made an open call for proposals regarding Kepler’s future operations on August 2. Today is the due date for submissions, which will undergo a review process until Nov. 1, 2013.
Added 9/4: For another take on this, check out Paul Gilster’s write-up on Centauri Dreams.
Have a discussion about the origins of the Universe and, ere long, someone will inevitably use the term “the Big Bang” to describe the initial moment of expansion of everything that was to everything that is. But in reality “Big Bang” isn’t a very good term since “big” implies size (and when it occurred space didn’t technically exist yet) and there was no “bang.” In fact the name wasn’t ever even meant to be an official moniker, but once it was used (somewhat derisively) by British astronomer Sir Fred Hoyle in a radio broadcast in 1949, it stuck.
Unfortunately it’s just so darn catchy.
This excellent video from minutephysics goes a bit more into depth as to why the name is inaccurate — even though we’ll likely continue using it for quite some time. (Thanks to Sir Hoyle.)
And you have to admit, a television show called “The Everywhere Stretch Theory” would never have caught on. Bazinga!
X-ray and infrared image of Sgr A*, the supermassive black hole in the center of the Milky Way
Like most galaxies, our Milky Way has a dark monster in its middle: an enormous black hole with the mass of 4 million Suns inexorably dragging in anything that comes near. But even at this scale, a supermassive black hole like Sgr A* doesn’t actually consume everything that it gets its gravitational claws on — thanks to the Chandra X-ray Observatory, we now know that our SMB is a sloppy eater and most of the material it pulls in gets spit right back out into space.
(Perhaps it should be called the Cookie Monster in the middle.*)
New Chandra images of supermassive black hole Sagittarius A*, located about 26,000 light-years from Earth, indicate that less than 1% of the gas initially within its gravitational grasp ever reaches the event horizon. Instead, much of the gas is ejected before it gets near the event horizon and has a chance to brighten in x-ray emissions.
The new findings are the result of one of the longest campaigns ever performed with Chandra, with observations made over 5 weeks’ time in 2012.
“This new Chandra image is one of the coolest I’ve ever seen,” said study co-author Sera Markoff of the University of Amsterdam in the Netherlands. “We’re watching Sgr A* capture hot gas ejected by nearby stars, and funnel it in towards its event horizon.”
As it turns out, the wholesale ejection of gas is necessary for our resident supermassive black hole to capture any at all. It’s a physics trade-off.
“Most of the gas must be thrown out so that a small amount can reach the black hole”, said co-author Feng Yuan of Shanghai Astronomical Observatory in China. “Contrary to what some people think, black holes do not actually devour everything that’s pulled towards them. Sgr A* is apparently finding much of its food hard to swallow.”
X-ray image of Sgr A*
If it seems odd that such a massive black hole would have problems slurping up gas, there are a couple of reasons for this.
One is pure Newtonian physics: to plunge over the event horizon, material captured — and subsequently accelerated — by a black hole must first lose heat and momentum. The ejection of the majority of matter allows this to occur.
The other is the nature of the environment in the black hole’s vicinity. The gas available to Sgr A* is very diffuse and super-hot, so it is hard for the black hole to capture and swallow it. Other more x-ray-bright black holes that power quasars and produce huge amounts of radiation have much cooler and denser gas reservoirs.
Illustration of gas cloud G2 approaching Sgr A* (ESO/MPE/M.Schartmann/J.Major)
Located relatively nearby, Sgr A* offers scientists an unprecedented view of the feeding behaviors of such an exotic astronomical object. Currently a gas cloud several times the mass of Earth, first spotted in 2011, is moving closer and closer to Sgr A* and is expected to be ripped apart and partially consumed in the coming weeks. Astronomers are eagerly awaiting the results.
“Sgr A* is one of very few black holes close enough for us to actually witness this process,” said Q. Daniel Wang of the University of Massachusetts at Amherst, who led the study.
It’s a new Symphony of Science video from melodysheep (aka John D. Boswell). It features Neil deGrasse Tyson, Lawrence Krauss, Michio Kaku, and Morgan Freeman. It’s about black holes.
The central peak of Bullialdus crater (Credit: NASA/GSFC/Arizona State University)
Scientists have detected magmatic water — water that originates from deep within the Moon’s interior — on the surface of the Moon. These findings represent the first such remote detection of this type of lunar water, and were arrived at using data from NASA’s Moon Mineralogy Mapper (M3) carried aboard India’s Chandrayaan-1 lunar orbiter.
The discovery represents an exciting contribution to the rapidly changing understanding of lunar water according to Rachel Klima, a planetary geologist at the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Md., and lead author of the paper, “Remote detection of magmatic water in Bullialdus Crater on the Moon” published in the August 25 issue of the journal Nature Geoscience.
Chandrayaan-1, India’s first mission to the Moon, entered lunar orbit on Nov. 8, 2008
“For many years, researchers believed that the rocks from the Moon were ‘bone dry’ and that any water detected in the Apollo samples had to be contamination from Earth,” said Klima, a member of the NASA Lunar Science Institute’s (NLSI) Scientific and Exploration Potential of the Lunar Poles team. “About five years ago, new laboratory techniques used to investigate lunar samples revealed that the interior of the Moon is not as dry as we previously thought. Around the same time, data from orbital spacecraft detected water on the lunar surface, which is thought to be a thin layer formed from solar wind hitting the lunar surface.”
“This surficial water unfortunately did not give us any information about the magmatic water that exists deeper within the lunar crust and mantle, but we were able to identify the rock types in and around Bullialdus crater,” said co-author Justin Hagerty, of the U.S. Geological Survey. “Such studies can help us understand how the surficial water originated and where it might exist in the lunar mantle.”
LRO image of the 60-km Bullialdus crater (NASA/GSFC/Arizona State University)
M3 (pronounced “M-cube”) fully imaged the large impact crater Bullialdus in 2009. “It’s within 25 degrees latitude of the equator and so not in a favorable location for the solar wind to produce significant surface water,” Klima explained. “The rocks in the central peak of the crater are of a type called norite that usually crystallizes when magma ascends but gets trapped underground instead of erupting at the surface as lava. Bullialdus crater is not the only location where this rock type is found, but the exposure of these rocks combined with a generally low regional water abundance enabled us to quantify the amount of internal water in these rocks.”
After examining the M3 data, Klima and her colleagues found that the crater has significantly more hydroxyl — a molecule consisting of one oxygen atom and one hydrogen atom — compared to its surroundings. “The hydroxyl absorption features were consistent with hydroxyl bound to magmatic minerals that were excavated from depth by the impact that formed Bullialdus crater,” Klima writes.
The internal magmatic water provides information about the Moon’s volcanic processes and internal composition, Klima said. “Understanding this internal composition helps us address questions about how the Moon formed, and how magmatic processes changed as it cooled. There have been some measurements of internal water in lunar samples, but until now this form of native lunar water has not been detected from orbit.”
“This impressive research confirms earlier lab analyses of Apollo samples, and will help broaden our understanding of how this water originated and where it might exist in the lunar mantle.”
UV image of Titan acquired by Cassini on April 13 (NASA/JPL-Caltech/SSI)
As high summer slowly but steadily approaches on Saturn, Cassini is opening a window to the seasonal changes that occur not only on the ringed planet but also its moons. Here we can see a dark band developing around Titan’s north polar latitudes, a “fancy collar” made visible in ultraviolet wavelengths.
Polar collars have previously been seen by both Hubble and Voyager 2, and in fact a southern version was observed by HST 5 years after the planet’s 1995 equinox.
This summer collar is thought to be part of a seasonal process, related to the migration of upper-level haze material within Titan’s atmosphere.
Source: CICLOPS (Cassini Imaging Central Laboratory for OPerationS)
The Solar System: it’s our home in space, the neighborhood that we all grew up in and where — unless we figure out a way to get somewhere else — all of our kids and grandkids and great-great-great-great-times-infinity-great-grandkids will grow up too. That is, of course, until the Sun swells up and roasts Earth and all the other inner planets to a dry crunchy crisp before going into a multi-billion year retirement as a white dwarf.
But until then it’s a pretty nice place to call home, if I may say so myself.
Edu-film designer Philipp Dettmer and his team have put together a wonderful little animation explaining the basic structure of the Solar System using bright, colorful graphics and simple shapes to illustrate the key points of our cosmic neighborhood. It won’t teach you everything you’ll ever need to know about the planets and it’s not advisable to use it as a navigation guide, but it is fun to watch and well-constructed, with nice animation by Stephan Rether and narration by Steve Taylor.
Check out the full video below:
“Through information design, concepts can be made easy and accessible when presented in a short, understandable edu-film or perhaps an infographic. Whether explaining the vastness of the universe or the tiniest building blocks of life – all information can be presented in a way that everyone understands. Regardless of prior knowledge.”
– Philipp Dettmer
(And come on, admit it… you learned something new from this!)
On July 16, Expedition 36 astronauts Chris Cassidy and Luca Parmitano had to cut a planned 7-hour spacewalk short after only an hour and a half due to a malfunction in Parmitano’s space suit, leaking water into his helmet and eventually cutting off his vision, hearing, and communications. Fortunately the Italian test pilot was able to safely return inside the ISS, but for several minutes he was faced with a pretty frightening situation: stuck outside Space Station with his head in a fishbowl that was rapidly filling with water.
On August 20, he shared his personal account of the event on his ESA blog.
“The only idea I can think of is to open the safety valve by my left ear: if I create controlled depressurisation, I should manage to let out some of the water, at least until it freezes through sublimation, which would stop the flow. But making a ‘hole’ in my spacesuit really would be a last resort…”
Parmitano’s description of his suit mishap begins as I’m sure all spacewalks do: with a sense of energy and enthusiasm for a job about to be performed in a challenging yet exotic and undeniably privileged location.
“My eyes are closed as I listen to Chris counting down the atmospheric pressure inside the airlock – it’s close to zero now. But I’m not tired – quite the reverse! I feel fully charged, as if electricity and not blood were running through my veins. I just want to make sure I experience and remember everything. I’m mentally preparing myself to open the door because I will be the first to exit the Station this time round. Maybe it’s just as well that it’s night time: at least there won’t be anything to distract me.”
But even though the EVA initially progressed as planned — ahead of schedule, in fact — it soon became obvious to Parmitano that something was amiss with his suit.
“The unexpected sensation of water at the back of my neck surprises me – and I’m in a place where I’d rather not be surprised. I move my head from side to side, confirming my first impression, and with superhuman effort I force myself to inform Houston of what I can feel, knowing that it could signal the end of this EVA.”
Luca Parmitano on EVA on July 16, 2013. (ESA)
It didn’t take long before an uncomfortable situation escalated into something potentially very dangerous.
“As I move back along my route towards the airlock, I become more and more certain that the water is increasing. I feel it covering the sponge on my earphones and I wonder whether I’ll lose audio contact. The water has also almost completely covered the front of my visor, sticking to it and obscuring my vision. I realise that to get over one of the antennae on my route I will have to move my body into a vertical position, also in order for my safety cable to rewind normally. At that moment, as I turn ‘upside-down’, two things happen: the Sun sets, and my ability to see – already compromised by the water – completely vanishes, making my eyes useless; but worse than that, the water covers my nose – a really awful sensation that I make worse by my vain attempts to move the water by shaking my head. By now, the upper part of the helmet is full of water and I can’t even be sure that the next time I breathe I will fill my lungs with air and not liquid. To make matters worse, I realise that I can’t even understand which direction I should head in to get back to the airlock. I can’t see more than a few centimetres in front of me, not even enough to make out the handles we use to move around the Station.”
After contemplating opening a hole in his helmet to let out some of the water — a “last resort,” indeed — Parmitano managed to get back inside the airlock with help from Cassidy. But he still had to deal with the process of repressurization, which itself takes a few minutes.
“I try to move as little as possible to avoid moving the water inside my helmet. I keep giving information on my health, saying that I’m ok and that repressurization can continue. Now that we are repressurizing, I know that if the water does overwhelm me I can always open the helmet. I’ll probably lose consciousness, but in any case that would be better than drowning inside the helmet.”
Now, a month after the mishap, Parmitano reflects on the nature of the event and of space travel in general.
“Space is a harsh, inhospitable frontier and we are explorers, not colonisers. The skills of our engineers and the technology surrounding us make things appear simple when they are not, and perhaps we forget this sometimes.”
ESA astronaut Luca Parmitano is the first of ESA’s new generation of astronauts to fly into space. Luca will serve as flight engineer on the Station for Expeditions 36 and 37. He qualified as a European astronaut and was proposed by Italy’s ASI space agency for this mission.
Polar mesospheric clouds shine over a midnight sunrise above Alaska on August 4, 2013 (NASA)
Looking for a new desktop background? This might do nicely: a photo of noctilucent “night-shining” clouds seen above a midnight Sun over Alaska, taken from the ISS as it passed over the Aleutian Islands just after midnight local time on Sunday, August 4.
When this photo was taken Space Station was at the “top of the orbit” — 51.6 ºN, the northernmost latitude that it reaches during its travels around the planet.
According to the NASA Earth Observatory site, “some astronauts say these wispy, iridescent clouds are the most beautiful phenomena they see from orbit.” So just what are they? Read on…
Found about 83 km (51 miles) up, noctilucent clouds (also called polar mesospheric clouds, or PMCs) are the highest cloud formations in Earth’s atmosphere. They form when there is just enough water vapor present to freeze into ice crystals. The icy clouds are illuminated by the Sun when it’s just below the horizon, after darkness has fallen or just before sunrise, giving them their eponymous property.
NLCs seen in the southern hemisphere in Jan. 2010 (NASA)
Noctilucent clouds have also been associated with rocket launches, space shuttle re-entries, and meteoroids, due to the added injection of water vapor and upper-atmospheric disturbances associated with each. Also, for some reason this year the clouds appeared a week early.
Some data suggest that these clouds are becoming brighter and appearing at lower latitudes, perhaps as an effect of global warming putting more greenhouse gases like methane into the atmosphere.
“When methane makes its way into the upper atmosphere, it is oxidized by a complex series of reactions to form water vapor,” said James Russell, the principal investigator of NASA’s Aeronomy of Ice in the Mesosphere (AIM) project and a professor at Hampton University. “This extra water vapor is then available to grow ice crystals for NLCs.”
A comparison of noctilucent cloud formation from 2012 and 2013 has been compiled using data from the AIM spacecraft. You can see the sequence here.
And for an incredible motion sequence of noctilucent clouds — taken from down on the ground — check out the time-lapse video below by Maciej Winiarczyk, coincidentally made at around the same time as the ISS photo above:
(The video was featured as the Astronomy Picture of the Day (APOD) for August 19, 2013.)
