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We’ve been so crazy following our own whims through the universe that we’ve neglected your questions. That ends today. It’s time to dig deep into our overflowing email box to retrieve the puzzling questions our listeners have sent in.
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Questions Show #8 – Show notes and transcript
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Occasionally, stars minding their own business around the supermassive black hole at the center of our galaxy get chucked out of the Milky Way, never to return. Fraser wrote about the discovery of two of these exiled stars, hurling away at the mind-blowing speed of over 1 million miles an hour. A recent study of another shows that not all of them originate in the center of our own galaxy.
New results from astronomers at the Carnegie Institute show that one star rocketing away from the Milky Way hearkens from the Large Magellanic Cloud, our neighboring galaxy. There have been ten such hypervelocity stars discovered, but where this one came from was quite a conunudrum.
Named HE 0437-5439, it’s nine times the mass of the Sun, and is traveling at 1.6 million miles an hour (2.6 million km an hour). The origin of the star has been a mystery until now because of its youth: it is 35 million years old, but it would have taken 100 million years to get to its current location if it were from the center of the Milky Way.
This meant that the star either came from somewhere else, or had to have formed out of the merger of two low-mass stars from the Milky Way, a so-called “blue straggler.”
Carnegie astronomers Alceste Bonanos and Mercedes López-Morales, and collaborators Ian Hunter and Robert Ryans from Queen’s University Belfast took measurements of the composition of the star – the first time this has been done on any hypervelocity star – and determined that its metal-poor makeup pointed towards the Large Magellanic Cloud as the former home of the castaway.
Bonanos said,“We’ve ruled out that the star came from the Milky Way. The concentration of [heavy] elements in Large Magellanic Cloud stars are about half those in our Sun. Like evidence from a crime scene, the fingerprints point to an origin in the Large Magellanic Cloud.�
Hypervelocity stars get their kick of energy from their interaction with a black hole. The stars were once part of a binary system, and as one star in the system gets captured by the black hole, the other is abruptly released, booting it clear out of the galaxy.
The mere fact that the Large Magellanic Cloud produced this hyperfast star hints at the presence of a black hole there, which has never previously been observed to exist.
Source: Carnegie Institute Press Release
UK astronomers have been dealt a serious and unexpected blow. Funding cuts to space research has stopped the nation from continuing its work at the Gemini observatories in Hawaii and Chile. The UK helped to build the 8.1 meter telescopes and have ploughed £70 million ($140 million) to date into the construction and development of the sites since the late 1990’s. In an effort to plug a £80 million ($160 million) deficit in space research funding, the Science and Technology Facilities Council (STFC) has signalled to researchers that the UK will be pulling out of the project, leaving astronomers bemused and angry.
Next month, the UK’s involvement in the multi-national Gemini project will end. After a decade of construction and research, the world’s most advanced telescopes will lose one of their most influential donors as the STFC has declared the British involvement in the project surplus to the government’s vision for the future of UK science. This decision will leave the US, Canada, Chile, Australia, Brazil and Argentina to continue astronomy without their 23.8% shareholder. The move has bewildered astronomers as the Gemini project is considered to be one of the most successful international collaborations in recent years, allowing the seven nation “science club” to observe both hemispheres’ night sky with unparalleled clarity.
“To withdraw from the state-of-the-art Gemini facilities leaves the UK ground-based astronomy strategy in disarray – some would say deliberately sabotaged.” – Professor Paul Crowther, Sheffield University, UK.
This move by the STFC highlights the recent turbulence in physics funding. After the merger of two of the largest research councils in the UK, the Particle Physics and Astronomy Research Council (PPARC) and the Central Laboratory of the Research Councils (CCLRC), the STFC was formed and inherited the unenviable task to find the money to cover the research funding deficit. New prestige facilities such as the Diamond Synchrotron, in Oxfordshire, are over-budget and the shortfall has to be found elsewhere. Requests have been made to the UK government for more funds, but the request has fallen on deaf ears. International research has therefore suffered, with more cuts in astronomy, particle physics and laser optics forecast. Jobs will be lost and the prediction is that the UK will have some of the most advanced physics research centers, but with no scientists to do the research.
The Gemini project is just one of the recent casualties during these dim times for UK physics. A campaign website outlining all the recent cutbacks by the STFC funding crisis has been set up to bring attention to the spiralling problem. The banner reads: “International Year Of Astronomy, 2009 (unless you’re from the UK*). The Universe – Yours To Discover. *All we could afford was this logo.” – STFC Funding Crisis: Astronomy.
Worrying times for the UK, and international physics as a whole.
Sources: BBC website
You know this is a burning question on the minds of eight-year olds everywhere: if you threw a boomerang in zero-gravity, would it come back to you? Japanese astronaut Takao Doi plans to test this very premise when he travels to the International Space Station in March 2008.
Doi plans to bring a paper boomerang to the ISS to test whether it will perform the trick of returning to the thrower in zero-gravity. He reportedly decided to test the boomerang at the behest of Yasuhiro Togai, a world boomerang champion from Osaka, Japan. With the announcement that a paper airplane will be launched from the ISS, space is beginning to look like an unruly high school classroom. But these experiments aren’t all fun and games, as there are underlying physical principles that can be explored by such simple tests.
A returning boomerang – when thrown properly – will travel in a circular path which brings it back around to the thrower. The two (or three) fins of a boomerang are shaped like an airplane wing, so when thrown the shape provides lift and causes the boomerang to fly.
Boomerangs fly in a circle because of the lift provided by the leading fin of the boomerang. Because it is spinning around a central axis, one fin provides lift in the direction of travel, then the other does the same. This force in the same direction makes the path of the boomerang form a circle, and as it loses energy because of the pull of gravity the boomerang comes back down to the ground.
Now, the question remains as to what will happen if the force of gravity is not present. The zero-gravity environment of the ISS is a perfect place to test this. The atmosphere of the ISS will still allow the boomerang to generate lift, but will it return to the sender, bounce off the walls, or just spin in place?
Source: Space Travel report
British scientists are working to build an invisible magnetic “Ion Shield” to be used during missions in space. A minature solar wind has been created in an Oxfordshire laboratory to simulate the highly charged particles emitted from the Sun and a magnetic “bubble” is being conceived to surround future spaceships. The magnetic field should have sufficient deflecting strength to redirect cancer-causing energetic particles away from future astronauts. Useful, especially during the proposed long-haul flights to Mars should the Sun begin launching flares at the wrong time…
The protection of astronauts in space from being bathed in damaging solar radiation is paramount to mission planners. Preventing exposure to high-energy particles is essential for the short-term success of the mission, and for the long-term health of the astronaut. Generally, humans in Earth orbit are protected from the ravages of the solar wind as they are within the protective blanket surrounding our planet. The protection is supplied by Earth’s magnetosphere, a powerful magnetic shield that deflects charged particles and channels them to the north and south poles, allowing life to thrive down here on the surface. The particles injected into the poles react with our atmosphere generating light, the Aurora.
So, the UK team are looking to create a small-scale “magnetosphere” of their own. If a spaceship can generate its own magnetic field, then perhaps the majority of solar particles can be deflected, creating a protective bubble the ship can travel in during solar storms. This may sound like science fiction, but the physics is sound, magnetic fields are used every day to deflect charged particles. Why not try to build a spaceship-sized magnetic particle deflector?
“We now have actual measurements that show a ‘hole’ in the solar wind could be created in which a spacecraft could sit, affording some protection from ‘ion storms’, as they would call them on Star Trek.” – Dr Ruth Bamford, physicist at the Rutherford Appleton Laboratory (RAL) in Chilton, Oxfordshire.
Firing a jet of charged particles into a strong magnetic field was attempted in the laboratory and the results were excellent. Observing the particles “hit” the leading edge of the field, a protected volume was made within the synthetic solar wind, arcing the particles around the void.
These are very early results however, and development on any large-scale system will take some work. Lots of energy would be required to create a spaceship-sized magnetic bubble, so there will be energy optimization issues to work into the design. Whether this exciting form of protection is possible or not, the pressure will be on to build a prototype before plans for the international Global Exploration Strategy to send man back to the Moon and beyond come into action. The US is now committed to a manned mission to Mars by 2020, so it would be useful to have the solar wind, high-energy particle problem solved by then.
Source: Guardian.co.uk
After all the excitement surrounding the possibility of asteroid 2007 WD5 hitting Mars and the concern of Near Earth Asteroid 2007 TU24 dropping to Earth, we now have something new (and manmade) to worry about. A US spy satellite has lost power and its orbit has begun to degrade. Officials are sketchy about the details, but the large satellite could survive the burn of re-entry and crash into the surface… but we don’t know where. The satellite might contain dangerous materials… but we can’t be sure. Either way, the dead spy satellite is expected to drop to Earth late February or early March.
This event could prove embarrassing for the US government, as there is little idea where the site of impact will be, sensitive US secrets could be exposed about the technology behind the orbital capabilities of the superpower nation. Officials have declined to comment whether the satellite could be shot down by missile, but this will surely remain an option.
“Numerous satellites over the years have come out of orbit and fallen harmlessly. We are looking at potential options to mitigate any possible damage this satellite may cause.” – Spokesman for the National Security Council, Gordon Johndroe
The problem doesn’t stop with the possibility of fatal damage should the satellite fall in the wrong place. An anonymous official has added there may be the possibility the satellite could be carrying hazardous materials. During atmospheric burn-up, this unknown material could be spread over thousands of miles of atmosphere.
This usually isn’t a concern when satellites and other debris are brought to Earth in controlled re-entries. Large defunct satellites can usually have their orbital trajectories finely tuned so they fall safely though the atmosphere and crash into “satellite graveyards” in deep ocean trenches (i.e. the Mir space station was guided out of orbit in 2001 and sunk in the Pacific 6000 km off the Australian coast).
Hopefully a solution to this tricky problem can be found quickly, but it is hoped that most of the satellite will disintegrate during re-entry and any leftovers drop into the ocean… but it would be nice to know if there is a risk of impact anywhere other than the oceans.Â
Source: MSNBC.com
Backyard astronomers the world over in the northern hemisphere are looking forward to the closest approach of Near-Earth Asteroid TU24 on the evening of January 29/30 – but just scanning the skies with a small telescope isn’t going to reveal the small, faint traveler. Like trying to find a single running squirrel in a huge forest, Asteroid TU24 will be on the move and success at spotting the target will only happen if you know in advance when to watch the right trees. Or in this case… the stars!
If you’d like to try your hand at observing Near-Earth Asteroid TU24, begin a little in advance by understanding exactly how bright it’s going to be. For just a period of a few hours, TU24 is expected to brighten to around magnitude 11 – considerably fainter than most star charts list. Since the event won’t be visible to the Southern Hemisphere, let’s begin our “capture” expedition by understanding what magnitude 11 and moving should look like. Your mission? Aim your telescope at Polaris!
Polaris is an excellent choice to learn from not only because there are few bright stars nearby, but because the ones around it will circle it over an extended period of time. Once you’ve located Polaris, take a look in your lower power eyepiece and compare what you see to this generation. No stars shown here are fainter than magnitude 11, so Near Earth Asteroid TU24 will appear much like these fainter stars. Because Polaris will not “move”, come back in an hour and see how the field has changed!
Now, let’s take a look at the general location where Near Earth Asteroid TU24 will pass – the center of this map . As you can see from this chart, if we could see magnitude 11 with just our eyes, Ursa Major would be lost in a forest of stars… And so would our squirrel. We know the asteroid will pass through the center of this area at a certain date and time… But we need to get just a little more specific. In order to spot the squirrel in the forest, it’s going to require some very clear directions as to what trees to watch when it passes by. A good place to begin is to visit this link to JPL/NASA’s New Horizons system to generate coordinates called an ephemerides. Because the squirrel would appear in a slightly different position relative to the tree’s branches depending on your position, you need to take extra care when using the New Horizons generator to be specific about your location and remember the information it supplies is expressed in universal time. For example, the starry background at local midnight for London, England would be totally different than the skies seen at local midnight for Palomar Observatory in southern California! We might be looking at the right tree, but to see the squirrel we need to know exactly what branches it is going to be passing by.
When the ephemerides is generated specifically for your location, there will be a long list of numbers that can be confusing if you are first learning astronomy. For those with “Go To” telescopes, it will be as easy as entering the coordinates that are supplied. For example, if we were to observe from Palomar Observatory, we’d put Right Ascension 10 00 50.64 and Declination +64 58 12.5 into the telescope’s system to observe the asteroid at midnight universal time. For those familiar with star charts, the same holds true – use the RA and Dec to pinpoint which star field you need to observe as the asteroid passes. For those who have neither, try visiting at site which will create maps for you, such as Your Sky. Using the “aim virtual telescope” feature, enter the coordinates that New Horizons provides for your location, then customize the chart to your specific needs. Now you know what tree to watch in the forest, what branch, what time the squirrel will pass and how bright he’ll be… But what will he look like?
Using our Palomar example once again, take a look at this photographic plate of the region. Thanks to parallax, Near Earth Asteroid TU24 will move quietly and purposefully across a starry field that will look just like this. It is possible at first glance to find what “star” doesn’t belong in the picture, but watching the field for a length of time will reveal movement – possibly even passing over (occulting) a field star and causing the background star to dim. Scientists will use information like this to help determine the exact size and shape of Asteroid TU24, but we’ll be happy if we just manage to spot the squirrel!
Be sure to dress warmly, and prepare yourself to take notes if at all possible. If an occultation occurs, note the time and duration. The more eyes we have on the skies, the better our chances will be of understanding visitors like Near Earth Asteroid TU24. Objects like these pass by frequently and by educating ourselves and others we make the natural (and safe) mechanics of our galaxy more understood to others! Good luck…
In case you had any doubts, it’s now official: Asteroid 2007 TU 24 will not impact or have any affect on Earth. Astronomers have obtained the first images of the near earth asteroid using high-resolution radar data. “With these first radar observations finished, we can guarantee that next week’s 1.4-lunar-distance approach is the closest until at least the end of the next century,” said Steve Ostro, Jet Propulsion Laboratory astronomer and principal investigator for the project. “It is also the asteroid’s closest Earth approach for more than 2,000 years.”
The radar images indicate the asteroid is somewhat asymmetrical in shape, with a diameter roughly 250 meters (800 feet) in size. Asteroid 2007 TU24 will pass within 1.4 lunar distances, or 538,000 kilometers (334,000 miles), of Earth on Jan. 29 at 12:33 a.m. Pacific time (3:33 a.m. Eastern time). So, while this image is pretty faint, (about 20 meters per pixel) as the asteroid gets closer, NASA will be able to obtain better images and more details about the object.
And just to repeat for anyone who still has any doubts, the scientists at NASA’s Near-Earth Object Program Office at JPL have determined that there is no possibility of an impact with Earth in the foreseeable future.
Asteroid 2007 TU24 was discovered by NASA Oct. 11, 2007. The asteroid should be visible to amateur astronomers using 3 inch (7.6 centimeter) telescopes. It will be brightest on January 29-30, reaching an approximate apparent magnitude of 10.3, and then become fainter as it moves farther from Earth. Anyone looking for the asteroid with amateur telescopes will need dark and clear skies. An object with a magnitude of 10.3 is about 50 times fainter than an object just visible to the naked eye in a clear, dark sky.
NASA detects and tracks asteroids and comets passing close to Earth. The Near Earth Object Observation Program, commonly called “Spaceguard,” discovers, characterizes and computes trajectories for these objects to determine if any could be potentially hazardous to our planet. They use several different tracking devices including the Goldstone’s 70-meter diameter (230-foot) antenna that is capable of tracking a spacecraft traveling more than 16 billion kilometers (10 billion miles) from Earth.
Ostro and his team plan further radar observations of asteroid 2007 TU24 using the National Science Foundation’s Arecibo Observatory in Puerto Rico on Jan. 27-28 and Feb. 1-4.
Original News Source: JPL Press Release
The images coming from Mars seem to get better and better. Mars rover Opportunity is currently sitting in an alcove of Victoria Crater (called Duck Bay), in the Meridiani Planum region, carrying out rock sample analysis. The soon-to-be four year old robotic wheeled explorer has taken it’s fair share of pictures of the Martian landscape, but this most recent panoramic effort oozes with detail and color (and without a Red Planet Yeti in sight)…
The Mars Expedition Rovers (MER), Opportunity and Spirit have been trundling around on the Mars surface for nearly four years (can you believe it?), carrying out experiments on the Mars rock and regolith. These tests are be essential for future missions to the Red Planet. But, by far the most striking results come from the high definition, ground level images they transmit to Earth, to our computers and TV screens. And this panorama looking over the famous Victoria Crater is up there with the best pictures ever to be captured by the Mars rover missions.
This panorama comes from Opportunity‘s Pancam (panoramic camera) instrument taken over the course of 47 sols (or Martian days) from the 1,332nd to the 1,379th sol of the MER mission (from October 23 to December 11, 2007). Pancam applies three different filters (at 753, 535 and 432 nanometers – optical wavelengths, from red to blue) and mixes the three images to form this view. The color combination method helps the viewer to pick out features in the landscape and amplifies subtle color differences in the scene.
Probably the most startling features in the panorama are the rocky outcrops leading to the basin of the Victoria Crater toward the upper right of the image. On studying the scene, you can see tracks in the regolith formed by Opportunity‘s wheels leading up the slope in Duck Bay. The fine detail also reveals the cracked structure of the parched land stretch into the distance. The rover’s solar panels also display a feast of color, brightening up the red of the landscape.
See Duck Bay and the entrance to Victoria Crater in all its glory as a high-resolution image (very big file: 24MB, so be sure to have a fast connection, or a free morning – the wait will be worth it!). However, don’t expect to see anything of the much hyped Mars “Big Foot”, there ain’t no humanoids there…
Source: Physorg.com
Just so it’s clear in your mind: comets are dirty snowballs, asteroids are rocks. Got the difference? Wait… not so fast. Scientists studying the cometary dust picked up by NASA’s Stardust spacecraft, and they’re finding it’s surprisingly asteroid like.
When Stardust flew past comet Wild 2 in 2006, scientists knew they would be scooping up materials created with the very formation of the solar system. But they didn’t think the dust from Wild 2 would resemble meteorites more than ancient, unaltered comet.
Comets are thought to contain large amounts of primitive material in the Solar System. Both the ancient ices that formed out of the stellar disk, but also the rain of interstellar material falling into the Solar System.
According to researchers at Lawrence Livermore National Laboratory, the particles that fell off Wild 2 formed very close to the Sun when it was young. They had been baked and blasted by the intense ultraviolet radiation of a newly forming star. Furthermore, they didn’t find the kind of primordial materials and ices that should have been present on an ancient comet like Wild 2.
“The material is a lot less primitive and more altered than materials we have gathered through high altitude capture in our own stratosphere from a variety of comets,” said LLNL’s Hope Ishii, lead author of the research that appears in the Jan. 25 edition of the journal, Science. “As a whole, the samples look more asteroidal than cometary.”
But Wild 2 is clearly a comet and not an asteroid. It’s got a tail; what could be more cometlike? It’s a reminder that there isn’t a clearly defined line between the two objects – there’s a continuum between them.
The researchers were expecting to see very specific minerals in the Stardust samples that should be coming from comets: glass with embedded metal and sulfides, and sliver-like whiskers of the crystallin silicate enstatite. They found only a single sample of enstatite in their samples and it was oriented the wrong way.
There were similar minerals found, but the researchers realized that they were being created when particles from the comet slammed into the Stardust collector. They were able to recreate this process in the lab.
For future studies, the researchers are hoping to get their hands on larger-grained materials, called micro-rocks. These would suffer less alteration from the impact with the Stardust collectors.
Original Source: LLNL News Release