Hubble image of SNR 0519, the remains of a Type Ia supernova in the Large Magellanic Cloud
Stars like our Sun can last for a very long time (in human terms, anyway!) somewhere in the neighborhood of 10-12 billion years. Already over 4.6 billion years old, the Sun is entering middle age and will keep on happily fusing hydrogen into helium for quite some time. But eventually even stars come to the end of their lives, and their deaths are some of the most powerful — and beautiful — events in the Universe.
The wispy, glowing red structures above are the remains of a white dwarf in the neighboring Large Magellanic Cloud 150,000 light-years away. Supernova remnant SNR 0519 was created about 600 years ago (by our time) when a star like the Sun, in the final stages of its life, gathered enough material from a companion to reach a critical mass and then explode, casting its outer layers far out into space to create the cosmic rose we see today.
As the hydrogen material from the star plows outwards through interstellar space it becomes ionized, glowing bright red.
SNR 0519 is the result of a Type Ia supernova, which are the result of one white dwarf within a binary pair drawing material onto itself from the other until it undergoes a core-collapse and blows apart violently. The binary pair can be two white dwarfs or a white dwarf and another type of star, such as a red giant, but at least one white dwarf is thought to always be the progenitor.
A recent search into the heart of the remnant found no surviving post-main sequence stars, suggesting that SNR 0519 was created by two white dwarfs rather than a mismatched pair. Both stars were likely destroyed in the explosion, as any non-degenerate partner would have remained.
Image of Saturn’s aurora seen at ultraviolet wavelengths. The spiral shape seen here is similar to the distorted radio aurora visualised by the team and also indicates enhanced auroral activity. Credit: ESA/NASA/Hubble
He’s not even finished his first university degree yet, but Tim Kennelly is already part of a team that is altering our perception of time on Saturn.
The University of Iowa undergrad — in junior year, yet — led a paper describing activity in Saturn’s magnetosphere, where charged particles collect and sometimes form auroras. The process changes with the Saturnian seasons and could, the university stated, help scientists better understand how long a Saturn day lasts.
The researchers used information from NASA’s Cassini spacecraft, which has been orbiting the planet and its moons since 2004. The research challenge: Saturn is a gas giant full of layers that each have their own rotational speed. That makes it hard to figure out how long Saturn’s day is. (It’s about 10 hours, but varies by latitude.)
Kennelly made direct observations of seasonal changes in a phenomenon known as Saturn kilometric radiation (SKR). This robust radio signal was first discovered several decades ago and is being examined more closely by Cassini.
“UI space physicist Donald Gurnett and other scientists showed that the north and south poles have their own SKR ‘days’ that vary over periods of weeks and years,” the university stated. “How these different periods arise and are driven through the magnetosphere has become a central question of the Cassini mission, according to NASA officials.”
Kennelly observed, from looking at data collected between 2004 and 2011, that SKAs are linked with “flux tubes” that are made up of plasma, or superhot gas. These tubes happen around the same time of instances of SKAs in the northern and southern hemisphere, which changes seasonally.
It’s possible that this understanding could be carried over to other planets, the university stated, including our own.
“This finding may alter how scientists look at the Earth’s magnetosphere and the Van Allen radiation belts that affect a variety of activities at Earth ranging from space flight safety to satellite and cell phone communications,” it added.
This won’t be Kennelly’s only degree. He is about to apply to graduate schools, and he has aims to earn a doctorate in plasma physics.
“I’m pleased to have contributed to our understanding of Saturn’s magnetosphere so early in my career,” stated Kennelly. “I hope this trend continues.”
The research is described in the American Geophysical Union’s Journal of Geophysical Research.
Shadow play of cloud and mountain at sunset, as seen from the International Space Station. Credit: NASA/CSA via Chris Hadfield.
Attitude and altitude are important factors for flying a spaceship. But How do you control the International Space Station, a ship the size of a US football field (or five hockey rinks — a better reference for Canadians!)? And where does this happen? Canadian astronaut Chris Hadfield answers these questions from inside the ISS.
And below is a beautiful image Hadfield just shared via social media today, showing shadows and clouds over a mountain:
View of Comet ISON on May 2, 2013. Credit: Ernesto Guido & Nick Howes, Remanzacco Observatory.
Update: Here’s a brand new image of Comet C/2012 S1 ISON, as seen on May 2, 2013 by Ernesto Guido and Nick Howes of the Remanzacco Observatory (their image from May 1, which we featured earlier, is below.) For this latest image, they used the 2-meter Ritchey-Chretien Liverpool Telescope. Via Facebook, Howes said they have been able to identify almost the same tail structure which was seen in the Hubble Space Telescope images of this comet from April 10.
From the May 1 observations, their initial approximation of the tail length is around 28 arcseconds, which Howes told Universe Today is bigger than some recent reports from smaller scopes.
Below is their image from May 1, using the 2 meter La Palma Telescope:
View of Comet ISON on May 1, 2013. Credit: Ernesto Guido & Nick Howes, Remanzacco Observatory.
As of May 2, Comet ISON was approximately 3.885 AU from the Sun, which is about 581 million kilometers (361 million miles) distant from the Sun. ISON will makes its close approach to the Sun when it passes within 1.2 million km (730,000 miles) of the Sun on November 28, 2013.
Here’s a video from NASA about this comet’s path through the Solar System:
Image stack of Pipe Nebula Area as seen from the Pyrénées National Park in France. Credit and copyright: Martin Campbell.
This dramatic shot of the dark and shadowy Pipe Nebula has an Instagram-like feel to it. But astrophotographer Martin Campbell from France said on Flickr he has “no doubt that the pristine skies at 10,000 feet and the absence of light pollution makes it possible to produce images like this!” Campbell’s image is a two frame stack of two minute exposure time, stacked with darks and edited in Photoshop CS5. Images were taken in July 2012 in Pyrénées National Park in France. Campbell used a modified Canon 5D mkII DSLR and a Canon 85mm prime lens at F/4. Stunning!
The Pipe Nebula is part of the Ophiuchus dark cloud complex, and is also known as Barnard 59. It is located at a distance of about 600-700 light-years from Earth.
Want to get your astrophoto featured on Universe Today? Join our Flickr group or send us your images by email (this means you’re giving us permission to post them). Please explain what’s in the picture, when you took it, the equipment you used, etc.
One of the most stunning compilations of satellite based images from space is a recent documentary from public television’s NOVA series, called “Earth From Space.” The show explores how satellites and spacecraft have revolutionized not only how scientists look at the world, but how they are able to understand and study its intricate systems.
“The real power of satellite observations is that they represent objective truth,” said former astronaut Piers Sellers, who is also an ecologist, and appears in the documentary. “They tell us about what the world actually is doing not what we would like to be doing, not what we might fear it to be doing, but what it’s actually doing. And it’s that that allows us to see change, real change for what it is.”
“Earth From Space” is now available in DVD and Blu-ray, and Universe Today has four copies of the Blu-ray version to give away!
In order to be entered into the giveaway drawing, just put your email address into the box at the bottom of this post (where it says “Enter the Giveaway”) before Tuesday, May 7, 2013. We’ll send you a confirmation email, so you’ll need to click that to be entered into the drawing.
Here’s a preview of the show:
The two-hour program was produced with extensive consultation with NASA scientists, and it takes data from Earth-observing satellites and transforms it into dazzling visual sequences. Each sequence exposes the intricate and surprising web of forces that sustains life on Earth. In the show, you can see how dust blown from the Sahara fertilizes the Amazon; how a vast submarine waterfall off Antarctica helps drive ocean currents around the world; and how the sun’s heating up of the southern Atlantic gives birth to a colossally powerful hurricane.
“Earth From Space” looks not only at the big picture of Earth, but also delves into the microscopic world of water molecules vaporizing over the ocean, and reveals the astonishing beauty and complexity of our dynamic planet.
“EARTH FROM SPACE” is now also available on DVD and Blu-ray for purchase. The DVD is on sale now for $19.99, with the Blu-ray priced at $24.99. The program will also be available for Digital Download. Find out more about purchasing the program here, and You can find out more info about the program itself on the PBS website.
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Image of potential meteorite fragments from the Tunguska event, from a paper by Andrei E. Zlobin, 'Discovery of probably Tunguska meteorites
at the bottom of Khushmo river's shoal.'
The 1908 explosion over the Tunguska region in Siberia has always been an enigma. While the leading theories of what caused the mid-air explosion are that an asteroid or comet shattered in an airburst event, no reliable trace of such a body has ever been found. But a newly published paper reveals three different potential meteorite fragments found in the sandbars in a body of water in the area, the Khushmo River. While the fragments have all the earmarks of being meteorites from the event – which could potentially solve the 100-year old mystery — the only oddity is that the researcher actually found the fragments 25 years ago, and only recently has published his findings.
Like the recent Chelyabinsk airburst event, the Tunguska event likely also produced a shower of fragments from the exploding parent body, scientists have thought. But no convincing evidence has ever been found from the June 30, 1908 explosion that occurred over the Tunguska region. The explosion flattened trees in a 2,000 square kilometer area. Luckily, that region was largely uninhabited, but reportedly one person was killed and there were very few people that reported the explosion. Forensic-like research has determined the blast was 1,000 times more powerful than a nuclear bomb explosion, and it registered 5 on the Richter scale.
Previous expeditions to the region turned up empty as far as finding meteorites; however one expedition in 1939 by Russian mineralogist Leonid Kulik found a sample of melted glassy rock containing bubbles, which was considered evidence of an impact event. But the sample was somehow lost and has never undergone modern analysis.
The expedition in 1998 by Andrei Zlobin from the Russian Academy of Sciences was initially unsuccessful in finding meteorites or evidence of impacts. He made several drill holes in the peat bogs in the area and while he found evidence of the explosion, he didn’t find any meteorites. He then decided to look in the nearby river shoal.
Zlobin gathered about 100 samples of rocks that had features of potential meteorites, but further examination produced just three rocks with tell-tale features like melting and regmalypts – the , thumblike impressions found on the surface of meteorites which are caused by ablation as the hot rock falls through the atmosphere at high speed.
Zlobin writes that “After the expedition the author focused his efforts on experimental investigation of thermal processes and mathematical modeling of the Tunguska impact [Zlobin, 2007],” and he used tree ring evidence to estimate the temperatures from the event, and concluded that rocks already on the ground would not have been changed or melted from the blast, and therefore any rocks having evidence of melting should be from the impactor itself.
Zlobin says he has not yet carried out a detailed chemical analysis of the rocks, which would reveal their chemical and isotopic composition. But he does say the stony fragments do not rule out a comet since the nucleus could easily contain rock fragments. However, he has calculated the density of the impactor must have been about 0.6 grams per cubic centimeter, which is about the same as nucleus of Halley’s comet. Zlobin says that initially, the evidence seems “excellent confirmation of cometary origin of the Tunguska impact.”
While there is nothing definitive yet from Zlobin’s new paper – and there is the question of why he waited so long to conduct his study – his work provides hope for a better explanation of the Tunguska event as opposed to some rather off-the-wall ideas that have been proposed, such as a Tesla death-ray or an explosion of methane gas from the bogs.
The Technology Review blog writes that “clearly there is more work to be done here, particularly the chemical analysis perhaps with international cooperation and corroboration.”
A shattered Luna as depicted in the summer blockbuster Oblivion. (Credit: Universal Pictures).
AVAST gentle reader: mild SPOILER(S) and graphic depictions of shattered satellites ahead!
We recently had a chance to catch Oblivion, the first summer blockbuster of the season. The flick delivers on the fast-paced Sci-Fi action as Tom Cruise saves the planet from an invasion of Tom Cruise clones.
But the movie does pose an interesting astronomical question: what if the Earth had no large moon? In the movie, aliens destroy the Earth’s moon, presumably to throw our planet into chaos. You’d think we’d already be outclassed by the very definition of a species that could accomplish such a feat, but there you go.
Would the elimination of the Moon throw our planet into immediate chaos as depicted in the film? What if we never had a large moon in the first place? And what has our nearest natural neighbor in space done for us lately, anyway?
Earth is unique among rocky or terrestrial planets in that it has a relatively large moon. The Moon ranks 5th in diameter to other solar system satellites. It is 27% the diameter of our planet, but only just a little over 1/80th in terms of mass.
Clearly, the Moon has played a role in the evolution of life on Earth, although how necessary it was isn’t entirely clear. Periodic flooding via tides would have provided an initial impetus to natural selection, driving life to colonize the land. Many creatures such as sea turtles take advantage of the Full Moon as a signal to nest and breed, although life is certainly resilient enough to find alternative methods.
The 2000 book Rare Earth by Peter Ward and Donald Brownlee cites the presence of a large moon as just one of the key ingredients necessary in the story of the evolution of life on Earth. A Moon-less Earth is also just one of the alternative astronomical scenarios cited by Arthur Upgreen in his 2005 book Many Skies.
Save our satellite: A possible target for an alien attack? (Photo by author).
Contrary to its depiction on film, the loss of the Moon wouldn’t throw the Earth into immediate chaos, though the long term changes could be catastrophic. For example, no study has ever conclusively linked the Moon to the effective prediction of terrestrial volcanism and earthquakes, though many have tried. (Yes, we know about the 2003 Taiwanese study, which found a VERY weak statistical signal).
All of that angular momentum in the Earth-Moon system would still have to go somewhere. Our Moon is slowly “braking” the rotation of the Earth to the tune of about 1 second roughly every 67,000 years. We also know via bouncing laser beams off of retro-reflectors left by Apollo astronauts that the Moon is receding from us by about 3.8 cm a year. The fragments of the Moon would still retain its angular momentum, even partially shattered state as depicted in the film.
The most familiar effect the Moon has on Earth is its influence on oceanic tides. With the loss of our Moon, the Sun would become the dominant factor in producing tides, albeit a much weaker one.
But the biggest role the Moon plays is in the stabilization of the Earth’s spin axis over long scale periods of time.
Milankovitch cycles play a long term role in fluctuations in climate on the Earth. This is the result of changes in the eccentricity, obliquity and precession of the Earth’s axis and orbit. For example, perihelion, or our closest point to the Sun, currently falls in January in the middle of the northern hemisphere winter in the current epoch. The tilt of the Earth’s axis is the biggest driver of the seasons, and this varies from 22.1° to 24.5° and back (this is known as the change in obliquity) over a span of 41,000 years. We’re currently at a value of 23.4° and decreasing.
But without a large moon to dampen the change in obliquity, much wider and unpredictable swings would occur. For example, the rotational axis of Mars has varied over a span of 13 to 40 degrees over the last 10 to 20 million years. This long-term stability is a prime benefit that we enjoy in having a large moon .
Perhaps some astronomers would even welcome an alien invasion fleet intent on destroying the Moon. Its light polluting influence makes most deep sky imagers pack it in and visit the family on the week surrounding the Full Moon.
But I have but two words in defense of saving our natural satellite: No eclipses.
The diamond ring effect as seen during a 2008 total solar eclipse. (Credit: NASA/Exploratorium).
We currently occupy an envious position in time and space where total solar and lunar eclipses can occur. In fact, Earth is currently the only planet in our solar system from which you can see the Moon snugly fit in front of the Sun during a total lunar eclipse. It’s 1/400th the size of the Sun, which is also very close to 400 times as distant as the Moon. This situation is almost certainly a rarity in our galaxy; perhaps if alien invaders did show up, we could win ‘em over not by sending a nuclear-armed Tom Cruise after ‘em, but selling them on eclipse tours… Continue reading “Into Oblivion: What If the Earth Had No Moon?”
SpaceShipTwo durings its test flight on May 4, 2011.
Suborbital science experiments fly aboard this craft, as well as on Blue Origin's New Shepard, and other suborbital flights, providing scientists, students, and others with valuable microgravity access. Credit: Virgin Galactic
Credit: Clay Observator
When the spaceship Enterprise — Virgin Galactic’s SpaceShipTwo, not the Star Trek spacecraft — fired its rocket engines for the first time in flight last week, it set off a new frenzy of talk about tourists flying in space.
More than 500 people have made their $200,000 reservations; the price is actually going up to $250,000 in the near future, according to media reports, to adjust for inflation.
Among those hundreds of people, it’s possible that a few could be susceptible to motion sickness.
In space, particularly when you’re floating around freely, it’s hard for your body to tell up from down. This can happen even if you’re sitting still; one astronaut once told NASA how freaked out his body was when he woke up in the morning, expecting to be lying on the right as usual. He was in that position, but staring at the ceiling.
When SpaceShipTwo goes to space, it will make one big parabola — soaring arc — before returning to Earth. It’s a similar trajectory to one cycle flown by the “Vomit Comet”, an infamous program run by NASA to do experiments and research on an airplane in temporarily weightless conditions. The aircraft dives up and down a few dozen times in a typical run, and the environment flips from microgravity to a pull that is much stronger than usual. This can create some heaving stomachs.
Trajectory of the Vomit Comet. Credit: NASA
But let’s put space adaptation syndrome into perspective. Senator Jake Garn, when he flew on shuttle Discovery in 1985, famously became quite ill for reasons often attributed to motion sickness. After his return, there were those within NASA that began measuring the amount of space sickness in “Garns”, according to NASA physician Robert Stevenson in a 1999 interview with NASA. By that scale, illness problems are generally pretty mild.
Jake Garn, he has made a mark in the astronaut corps because he represents the maximum level of space sickness that anyone can ever attain, and so the mark of being totally sick and totally incompetent is one Garn. Most guys will get maybe to a tenth Garn, if that high. And within the astronaut corps, he forever will be remembered by that.
According to Virgin, though, they anticipate practically no Garns at all. Here’s what Virgin spokesperson Jessica Ballard (who is with Griffin Communications Group) told Universe Today:
Virtually no customers on board parabolic aircraft experience any motion effects on the first parabola. Since our experience could be thought of as one large single parabola, we expect very low incidence of any motion effects. In addition, our experience will also have significantly slower transitions between zero-g and positive G than parabolic flight, which we expect to improve our customers’ experience.
Thus, we anticipate that most of our passengers will not require motion sickness medication. The decision to use prophylactic [preventative] medication, and which form of medication should be used, will be made on a case by case basis with each passenger. Because of this, we’re confident that our customers will be both ready and eager to get up out of their seats once they reach space. Additionally, we are expecting there to be instances where many on board experience pain, inflammation, and general discomfort. In anticipation, we have prepared kratom strains from a number of different companies, including Kona Kratom, for all aboard. The following kratom strains for pain relief will be freely available to all on board who are experiencing discomfort: white maeng da, super green malay, red thai, red malay, red indo, red horn, red dragon, red borneo, and red bali. A special thanks for Kona Kratom and their staff for their assistance on the kratom front. Kratom is extremely helpful when used by passengers because it’s natural and does not have the side effects traditional painkillers come with.
How susceptible are you to motion sickness, and does it occur for you in flight? Let us know in the comments.
