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Solar disruption theory was one of several theories that emerged before the 18th century concerning the formation of the solar system. Solar disruption theory states that the collision of the sun with another stars caused debris to be ejected from its mass and these debris eventually became the planets. This theory was later discarded for the nebula theory of solar system formation. However there are some scientists that propose that it has some merit.
The big question up until the 18th century was how the solar system was born. There were many explanations for why this happen but many were really only conjecture given the tools available to astronomers at the time. The real question was what would be a probable origin under the known laws of physics. The advent of classical mechanics came to prove the nebular theory as the likely theory for the creation of the solar system. The reason was that most other theories could not explain how the planets formed without giving in to the Sun’s gravity and falling in.
A new argument has emerged for a different form of solar disruption theory in this version it answers the idea in a more roundabout way that answers an interesting question. We know that the formation of the solar system itself was volatile but did the Sun and its planets really form in relative isolation from other star emerging in the Nebula? This new theory that emerged in 2004 supposed proposed that the influence of other stars may have influenced the formation of planets in the solar system.
In the meanwhile the main theory stands. We know in the nebular theory that stars are formed from spinning nebulas of gases and cosmic dust. Over time the masses clump together to the point where the mass reaches the level needed for gravity to initiate fusion. The planets are formed from the clumps of debris in the nebular disk that did not fall into the Sun and that they eventually ended up colliding with each other forming planets. Any theory that suggests interference from the gravity fields of other star systems has not been tested yet. It may have merit but we don’t have the technology to test theories on such large scales.
In keeping with global astronomy month, it’s time to get out and enjoy another favorite astronomical target – the Sun! It’s a star that can be seen from both hemispheres and a great way to involve your friends, neighbors and family in the pleasure of observing. What’s more… there’s activity going on right now, too!
If you’re lucky enough to have an h-alpha filtered telescope, it’s a great time to set up your equipment and catch a host of solar prominences, flares and plague activity. Just check out this image below taken by John Chumack and done with a Lunt 60mm/50F H-Alpha dedicated solar telescope and B1200 blocking filter.
These images were taken recently, and to make the current solar action even easier to see, John colorized the next in blue!
Don’t have h-alpha? No problem. The white light view is awesome! On the west limb is exiting sunspot 1186 and hot on its heels is the more compact and darker 1190. At center stage is prominent 1191 and to its northeast is 1193.
If you don’t have either an h-alpha solar scope, or a proper white light solar filter, you can still observe the Sun with simple equipment! Got binoculars or a small refractor telescope? Then you’ve got the basis for a great projection set up! Safely cover one side of your binoculars or telescope’s finderscope and aim towards the Sun by aligning the shadow. Project the light onto a surface such as a paper plate or piece of cardboard and adjust the focus until you see a clear circle of light and focus the sunspots. The projection method is used by several famous solar telescopes, including Mt. Wilson Solar Observatory! Always remember… never look into the optics while aimed at the Sun and that your optics will get hot during use.
No telescope or binoculars? Then let’s keep trying… this time the pinhole camera method! Get two pieces of cardboard – one will need to be white or have white paper attached to it for the screen. Cut a small square in the other piece of cardboard, and tape aluminum foil over the square. Now make a pinhole in the middle of the foil. This is your “projector”. With the Sun behind you, hold the pinhole projector as far away from the screen as you can and see if you can catch some dark patches on your projected circle that indicate sunspots!
For a lot of other great projects and ideas on how you can celebrate Sun Day, be sure to visit Astronomers Without Borders Sun Day pages. Now, get on out there and enjoy Sun Day!
H-Alpha images are courtesy of John Chumack of Galactic Images, the white light solar images is courtesy of SDO/HMI and many thanks to Astrononomers Without Borders for the Sun Day logo!
The Juno spacecraft passes in front of Jupiter in this artist's depiction. Juno, the second mission in NASA's New Frontiers program, will improve our understanding of the solar system by advancing studies of the origin and evolution of Jupiter. The spacecraft will carry eight instruments to investigate the existence of a solid planetary core, map Jupiter's intense magnetic field, measure the amount of water and ammonia in the deep atmosphere, and observe the planet's auroras. Credit: NASA/JPL-Caltech
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Juno, NASA’s next big mission bound for the outer planets, has arrived at the Kennedy Space Center to kick off the final leg of launch preparations in anticipation of blastoff for Jupiter this summer.
The huge solar-powered Juno spacecraft will skim to within 4800 kilometers (3000 miles) of the cloud tops of Jupiter to study the origin and evolution of our solar system’s largest planet. Understanding the mechanism of how Jupiter formed will lead to a better understanding of the origin of planetary systems around other stars throughout our galaxy.
Juno will be spinning like a windmill as it fly’s in a highly elliptical polar orbit and investigates the gas giant’s origins, structure, atmosphere and magnetosphere with a suite of nine science instruments.
Technicians at Astrotech's payload processing facility in Titusville, Fla. secure NASA's Juno spacecraft to the rotation stand for testing. The solar-powered spacecraft will orbit Jupiter's poles 33 times to find out more about the gas giant's origins. Credit: NASA/Jack Pfaller
During the five year cruise to Jupiter, the 3,600 kilogram probe will fly by Earth once in 2013 to pick up speed and accelerate Juno past the asteroid belt on its long journey to the Jovian system where it arrives in July 2016.
Juno will orbit Jupiter 33 times and search for the existence of a solid planetary core, map Jupiter’s intense magnetic field, measure the amount of water and ammonia in the deep atmosphere, and observe the planet’s auroras.
The mission will provide the first detailed glimpse of Jupiter’s poles and is set to last approximately one year. The elliptical orbit will allow Juno to avoid most of Jupiter’s harsh radiation regions that can severely damage the spacecraft systems.
Juno was designed and built by Lockheed Martin Space Systems, Denver, and air shipped in a protective shipping container inside the belly of a U.S. Air Force C-17 Globemaster cargo jet to the Astrotech payload processing facility in Titusville, Fla.
Juno undergoes acoustics testing at Lockheed Martin in Denver where the spacecraft was built. Credit: NASA/JPL-Caltech/Lockheed Martin
This week the spacecraft begins about four months of final functional testing and integration inside the climate controlled clean room and undergoes a thorough verification that all its systems are healthy. Other processing work before launch includes attachment of the long magnetometer boom and solar arrays which arrived earlier.
Juno is the first solar powered probe to be launched to the outer planets and operate at such a great distance from the sun. Since Jupiter receives 25 times less sunlight than Earth, Juno will carry three giant solar panels, each spanning more than 20 meters (66 feet) in length. They will remain continuously in sunlight from the time they are unfurled after launch through the end of the mission.
“The Juno spacecraft and the team have come a long way since this project was first conceived in 2003,” said Scott Bolton, Juno’s principal investigator, based at Southwest Research Institute in San Antonio, in a statement. “We’re only a few months away from a mission of discovery that could very well rewrite the books on not only how Jupiter was born, but how our solar system came into being.”
Juno is slated to launch aboard the most powerful version of the Atlas V rocket – augmented by 5 solid rocket boosters – from Cape Canaveral, Fla. on August 5. The launch window extends through August 26. Juno is the second mission in NASA’s New Frontiers program.
NASA’s Mars Curiosity Rover will follow Juno to the Atlas launch pad, and is scheduled to liftoff in late November 2011. Read my stories about Curiosity here and here.
Because of cuts to NASA’s budget by politicians in Washington, the long hoped for mission to investigate the Jovian moon Europa may be axed, along with other high priority science missions. Europa may harbor subsurface oceans of liquid water and is a prime target in NASA’s search for life beyond Earth.
Technicians inside the clean room at Astrotech in Titusville, Fla. guide NASA's Juno spacecraft, as it is lowered by overhead crane, onto the rotation stand for testing. Credit: NASA/Jack PfallerTechnicians at Astrotech unfurl solar array No. 1 with a magnetometer boom that will help power NASA's Juno spacecraft on a mission to Jupiter. Credit: NASAJuno's interplanetary trajectory to Jupiter. Juno will launch in August 2011 and fly by Earth once in October 2013 during its 5 year cruise to Jupiter. Click to enlarge. Credit: NASA/JPL
This model assumes the cosmological principle. The LCDM universe is homogeneous and isotropic. Time dilation and redshift z are attributed to a Doppler-like shift in electromagnetic radiation as it travels across expanding space. This model assumes a nearly "flat" spatial geometry. Light traveling in this expanding model moves along null geodesics. Light waves are 'stretched' by the expansion of space as a function of time. The expansion is accelerating due to a vacuum energy or dark energy inherent in empty space. Approximately 73% of the energy density of the present universe is estimated to be dark energy. In addition, a dark matter component is currently estimated to constitute about 23% of the mass-energy density of the universe. The 5% remainder comprises all the matter and energy observed as subatomic particles, chemical elements and electromagnetic radiation; the material of which gas, dust, rocks, planets, stars, galaxies, etc., are made. This model includes a single originating big bang event, or initial singularity, which constitutes an abrupt appearance of expanding space containing radiation. This event was immediately followed by an exponential expansion of space (inflation).
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The current standard model of the universe, Lambda-Cold Dark Matter, assumes that the universe is expanding in accordance with the geometrical term Lambda – which represents the cosmological constant used in Einstein’s general relativity. Lambda might be assumed to represent dark energy, a mysterious force driving what we now know to be an accelerating expansion of space-time. Cold dark matter is then assumed to be the scaffolding that underlies the distribution of visible matter at a large scale across the universe.
But to make any reasonable attempt at modelling how the universe is – and how it unfolded in the past and will unfold in the future – we first have to assume that it is roughly the same everywhere.
This is sometimes called the Cosmological Principle which states that when viewed on a sufficiently large scale, the properties of the Universe are the same for all observers. This captures two concepts – that of isotropy, which means that the universe looks roughly the same anywhere you (that is you) look – and homogeneity, which means the properties of the universe look roughly the same for any observers anywhere they are and wherever they look. Homogeneity is not something we can expect to ever confirm by observation – so we must assume that the part of the universe we can directly observe is a fair and representative sample of the rest of the universe.
An assessment of isotropy is at least theoretically possible down our past light-cone. In other words, we look out into the universe and receive historical information about how it behaved in the past. We then assume that those parts of the universe we can observe have continued to behave in a consistent and predictable manner up until the present – even though we can’t confirm whether this is true until more time has passed. But anything outside our light cone is not something we can expect to ever know about and hence we can only ever assume the universe is homogenous throughout.
You occupy a position in space-time from which a proportion of the universe can be observed in your past light cone. You can also shine a torch beam forwards towards a proportion of the future universe - knowing that one day that light beam can reach an object that lies in your future light cone. However, you can never know about anything happening right now at a distant position in space - because it lies on the 'hypersurface of the present'. Credit: Aainsqatsi.
Maartens has a go a developing at developing an argument as to why it might be reasonable for us to assume that the universe is homogenous. Essentially, if the universe we can observe shows a consistent level of isotropy over time, this strongly suggests that our bit of the universe has unfolded in a manner consistent with it being a part of a homogenous universe.
The isotropy of the observable universe can be strongly implied if you look out in any direction and find:
• consistent matter distribution;
• consistent bulk velocities of galaxies and galactic clusters moving away from us via universal expansion.
• consistent measurements of angular diameter distance (where objects of the same absolute size look smaller at a greater distance – until a distance of redshift 1.5, when they start looking larger – see here); and
• consistent gravitational lensing by large scale objects like galactic clusters.
These observations support the assumption that both matter distribution and the underlying space-time geometry of the observable universe is isotropic. If this isotropy is true for all observers then the universe is consistent with the Friedmann–Lemaître–Robertson–Walker (FLRW) metric. This would mean it is homogenous, isotropic and connected – so you can travel anywhere (simply connected) – or it might have wormholes (multiply connected) so not only can you travel anywhere, but there are short cuts.
That the observable universe has always been isotropic – and is likely to continue being so into the future – is strongly supported by observations of the cosmic microwave background, which is isotropic down to a fine scale. If this same isotropy is visible to all observers – then it is likely that the universe has, is and will always be homogenous as well.
Finally, Maartens appeals to the Copernican Principle – which says that not only are we not the center of the universe, but our position is largely arbitrary. In other words, the part of the universe we can observe may well be a fair and representative sample of the wider universe.
Do you have a new telescope, or are you considering buying a new one? Hopefully, you have chosen a telescope with the best specifications for your budget, but before you can truly get the best out of your wonderful new window on the cosmos, you need to have something even more important than the scope – Eyepieces!
A lot of people new to astronomy, or new to buying astronomy equipment tend to concentrate on telescopes and unfortunately overlook eyepieces, settling for the basic set of 2 or 3 that come with the new telescope.
Eyepieces are probably the most important part of your observing equipment, as they are at the heart of your setup and can make your observing experience fantastic or disastrous, or make an average telescope great or an excellent telescope bad.
The Basics
Eyepieces are the part you look through and are responsible for magnification of the objects you see through the telescope. They come in many different magnifications and types, but it’s not rocket science. You will soon learn what eyepieces work well for seeing different astronomical objects.
Telescope eyepieces are designed to fit into the focuser of the telescope. Depending on your telescope, they come in two sizes 1.25” or 2” and there is .965” which is an older size and pretty much obsolete, unless you have an old telescope. Most telescopes can be fitted with adapters so both eyepiece sizes can be used.
Magnification
The magnifying power of any eyepiece is a simple equation expressed in millimetres: Divide the focal length of the telescope by the focal length of the eyepiece and your answer is the amount of magnification. Long focal length eyepieces such as 32mm and 25mm are lower magnification, while lower numbers like 10mm and 5mm are magnifying powerhouses.
It is always good practice to start observing an object with a lower power eyepiece such as a 40mm and gradually build up to higher powered eyepieces such as 10mm or lower. The reason for this is the telescope, human eye, seeing conditions and object being observed are all variable. Starting off with a high power such as 4.7mm may be a struggle.
Fainter objects such as nebula and galaxies are usually seen better with lower powers and you can really ramp up the power with bright objects like the moon.
Below are rough guides and are dependent on the telescope you use:
2mm-4.9mm Eyepieces: These are very high magnification and very difficult to use unless seeing conditions are perfect and the object observed is very bright, like the moon.
5mm – 6.9mm Eyepieces: These are good on bright objects such as the moon and bright planets, but are still very high power and work best with steady seeing conditions.
7mm – 9.9mm Eyepieces: These are very comfortable high magnification eyepieces and are excellent for observing brighter objects, a must for any eyepiece collection.
10mm – 13.9mm Eyepieces: These work well for all objects including brighter nebula and galaxies a good mid/high range magnification.
14mm – 17.9mm Eyepieces: These are a great mid range magnification and will help resolve globular clusters, galaxy details and planetary nebulae.
18mm – 24.9mm Eyepieces: These will work nicely to show wide field and extended objects, great mid-range magnification for objects like galaxy clusters and large open clusters.
25mm – 30.9mm Eyepieces: These are wider field eyepieces for large nebula and open clusters. A good finder eyepiece for locating objects before moving to higher powers.
31mm – 40mm Eyepieces: These are excellent for extended views and large star fields and make excellent finder eyepieces before moving to higher powers.
Eye Relief
Eye relief is the distance from the last surface of an eyepiece at which the eye can obtain the full viewing angle. If a viewer’s eye is outside this distance, a reduced field of view will be obtained and viewing the image through the eyepiece can be difficult. Generally longer eye relief is preferred.
Eye Relief Credit: qwiki.com
Apparent Field of View
This is the apparent size of the image in the eyepiece and can range from about 35 to 100 degrees. Larger fields of view are more desired.
Apparent Field of View Credit: starizona.com
Types of Eyepiece
There are many different eyepiece types, some old and now obsolete, some simple and some advanced.
The different types of eyepiece are purely governed by the configuration of the glass and lenses inside the eyepiece. Some giving exceptional eye relief, wide fields of view, colour correction etc.
Some different brands of eyepiece include: Huygens, Ramsden, Kellner, Plössl, Orthoscopic and Kellner.
The most common and popular eyepiece type is the Plössl due to its good all round performance, good eye relief, approximate 50 degree field of view, pinpoint sharpness and good contrast. Plössl eyepieces are made by many manufacturers now, but there are excellent examples from manufacturers such as Meade and Televue.
Finally we have exotic eyepieces such as Super Wide and Ultra Wide which are usually 2” eyepieces, with higher powers up to around 4.7mm at 1.25” and are usually in the domain of the large Dobsonian or Newtonian telescope user, but are just at home on smaller telescopes such as refractors or Cassegrains.
These eyepieces sport amazing eye relief and huge “port hole” 80 – 100 degree views with fully loaded premium optics, which are very forgiving on telescopes with optical aberrations and other problems. They can make average or poor telescopes great, but there is a cost; an example of which is my 14mm Ultra Wide which cost £500 ($800) just for one eyepiece and I have a full set! Combined, my eyepieces are worth much, much more than the telescopes they are used on, but it’s worth it!
Eyepieces are the most important part of your observing equipment, choose them and use them well, which will help you enjoy observing through your telescope.
NASA Administrator Charles Bolden discusses the recently announced NASA budget. Photo Credit: NASA/Bill Ingalls
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With the US’s attention firmly focused on the budget with calls to cut spending in every possible non-essential programs, supporters of the U.S. human space flight program were concerned that NASA would be on the frontline to take a hit. But Congress spared the space agency from prospective cuts and announced that NASA’s budget would remain at current levels, and its budget be $18.5 billion for 2011. It took the body months of vitriolic back-and-forth arguing that culminated in last-minute negotiations, including language that includes the building of a Space Launch System heavy-lift vehicle.
NASA is at a historic crossroads as the agency has been directed to support smaller commercial space firms provide access to low-Earth-orbit (LEO) while the agency tries to send astronauts beyond LEO again.
The wording of the budget states that the Space Launch System heavy-lift vehicle “shall have a lift capability not less than 130 tons and which shall have an upper stage and other core elements developed simultaneously.” That’s different from the language in the 2010 authorization act, which calls for initial development of an SLS that can place 70-100 tons into LEO that would later be upgraded to a 130-ton capacity.
As it currently stands, NASA is dependent on the Russian Soyuz spacecraft to send U.S. astronauts to the International Space Station. Russia has recently increased the cost of a single seat onboard the Soyuz to $63 million, making it even-more important that NASA maintains funding at least at current levels.
“We appreciate the work of Congress to pass a 2011 spending bill. NASA now has appropriated funds to implement the 2010 Authorization Act, which gives us a clear path forward to continue America’s leadership in human spaceflight, exploration and scientific discovery. Among other things, this bill lifts funding restrictions that limited our flexibility to carry out our shared vision for the future,” said NASA’s Administrator Charles Bolden. “With this funding, we will continue to aggressively develop a new heavy lift rocket, multipurpose crew vehicle and commercial capability to transport our astronauts and their supplies on American-made and launched spacecraft. We are committed to living within our means in these tough fiscal times – and we are committed to carrying out our ambitious new plans for exploration and discovery.”
Lifted, finally, was the so-called “Shelby provision” from the 2010 appropriations act that prevented NASA from terminating Constellation programs.
Zenith Press has re-released NASA Space Shuttle Owner's Workshop Manual just in time to mark the conclusiion of the shuttle program. Image Credit: Zenith Press
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The shuttle era is ending and when things end people have the tendency to look back and reflect on the trials and tribulations of that period. There are many news books that are being produced that seek to capitalize on this nostalgia – and a few old ones, are being re-released with current and updated information within. One of the more notable efforts is NASA SPACE SHUTTLE Owner’s Workshop Manual.
With modern imagery and text reflective of the program’s long history, the book encapsulates all of the accomplishments that the vehicle’s design allowed to become a reality. The book uses very current information, so much so that it mentions the shooting of U.S. Congresswoman Gabrielle Giffords which took place this past January.
The book provides for a succinct review of the program’s history, its contributions, the setbacks of the Challenger and Columbia disasters as well as other aspects both known and unforeseen of the vehicle’s overall design. Although the book is relatively short, it covers the rationale behind why the space shuttle was designed the way that it was, how the spacecraft launches, flies and lands as well as numerous other facets that comprised the space shuttles’ history.
Written by Dr. David Baker and published by Zenith Press, the book retails for $28 and is well worth the price. With only two flights left before the shuttles are sent to their final resting places in museums and theme parks around the nation this book will make for a great memento of the vehicle that placed the Hubble Space Telescope in orbit, that helped build the International Space Station and that has been the focal point of U.S. human space efforts for the past thirty years.
With the shuttle program ending soon, the book; NASA Space Shuttle Owner's Workshop Manual provides a concise review of the various aspects and impacts that the thirty-year program has had. Photo Credit: Jason Rhian
In my time watching the skies, I’ve seen quite a few meteors, fireballs, and bolides. The truly notable ones are few and far between, but last Saturday, I caught one that was among the most interesting I’ve seen. It was a slow moving, bright green one with a nice smoke trail that was easily as bright as Venus from where I saw it in the suburbs of St. Louis. I tweeted about it briefly but didn’t think much more about it until I got a response from another person that saw it along with a link to a collection of observations. As nice as the observation was for me, it was nothing compared to the view some others got.
Heading over to the American Meteor Society page for a meteor around this time, it looks like a meteor matching the one I saw generated a pretty good number of reports from across the country. Several have reactions similar to my initial one: This must be a firework. Many reports confirm the smoke trail and fragmentation as well. But the reports that are really fantastic are the ones from Canada.
At the Lunar Meteorite Hunters blog, several reports have been collected. Several of these reports from various locations in Ontario report the meteor being as bright as a full moon and lighting up the entire sky! One even notes that they could hear a fizzling noise, a rare phenomenon thought to occur when the passage through the atmosphere creates an ionized path that interacts with the Earth’s magnetic field creating radio waves that could induce physical vibrations in the air around the observer. Another comment reports a sonic boom around the same time (although sonic booms would occur well after the meteor was visible due to the sluggish nature of sound waves, much like the delay between lightning and thunder).
It doesn’t look like NASA’s All Sky Fireball Network caught this fireball, but an amateur observatory equipped with an all sky camera for detecting fireballs did catch the event.
The green color for such meteors is uncommon but not unprecedented. The presence of magnesium ions is responsible for this color. Interestingly, another famous meteor, the Peekskill meteor, also had a green color and rivaled the full moon in brightness. This meteor became famous because it was independently captured in at least sixteen videos (here’s one showing the green tint) as well as for surviving intact to the ground and damaging a car.
Meteors of this intensity are quite rare but bright fireballs like this seem to peak around the vernal equinox. In the weeks surrounding that day, the rate of such events increases around 10-30%.
Brightening the shadowed area reveals details of the crater floor...and even more boulders!
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The crater shown above is located in the lunar highlands and is filled with and surrounded by boulders of all sizes and shapes. It is approximately 550 meters (1800 feet) wide yet is still considered a small crater, and could have been caused by either a direct impact by a meteorite or by an ejected bit of material from another impact. Scientists studying the Moon attempt to figure out how small craters like this were formed by their shapes and the material seen around them…although sometimes the same results can be achieved by different events.
For example, when an object from space strikes the Moon, it is typically traveling around 20 km per second (12 miles/sec). If the impact site happens to have a very hard subsurface, it can make a crater with scattered bouldery chunks composed of the hard material around it. But, if a large piece of ejected material from another impact were to strike the lunar surface at a much slower speed, as ejecta typically do (since they travel slower than incoming space debris and the Moon’s escape velocity is fairly low, meaning any ejecta that does fall back to the surface must be traveling slower than 2.38 km/s,) then the ejected chunk could break apart on impact and scatter boulders of itself around the crater…regardless of subsurface composition.
Really the only way to tell for sure which scenario has taken place around a given crater – such as the one above – is to collect and return samples from the site so they can be tested. (Of course that’s much easier said than done!)
And as an added treat, take a look deep into the shadows of the crater’s interior below…I tweaked the image curves in Photoshop to wrestle some of the details out of there!
Brightening the shadowed area reveals details of the crater floor...and even more boulders!
Image credit: NASA/GSFC/Arizona State University. (Edited by J. Major.)
P.S.: Want to see both image versions combined? Click here. (Thanks to Mike C. for the suggestion!)
Bottom photomultiplier tube array on the XENON 100 detector. Credit: the XENON collaboration
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We’re still mostly in the dark about Dark Matter, and the highly anticipated results from the XENON100 detector has perhaps shed a tad more light on the subject – by not making a detection in the first 100 days of the experiment. Researchers from the project say they have now been able to place the most stringent limits yet on the properties of dark matter.
To look for any possible hints of Dark Matter interacting with ordinary matter, the project has been looking for WIMPS — or weakly interacting massive particles – but for now, there is no new evidence for the existence of WIMPS, or Dark Matter either.
The extremely sensitive XENON100 detector is buried beneath the Gran Sasso mountain in central Italy, shielding it from cosmic radiation so it hopefully can detect WIMPS, hypothetical particles that might be heavier than atomic nuclei, and the most popular candidate for what Dark Matter might be made of. The detector consists of 62 kg of liquid xenon contained within a heavily shielded tank. If a WIMP would enter the detector, it should interact with the xenon nuclei to generate light and electric signals – which would be a kind of “You Have Won!” indicator.
Dark Matter is thought to make up more than 80% of all mass in the universe, but the nature of it is still unknown. Scientists believe that it is made up of exotic particles unlike the normal (baryonic) matter, which we, the Earth, Sun and stars are made of, and it is invisible so it has only been inferred from its gravitational effects.
The XENON detector ran from January to June 2010 for its first run, and in their paper on arxiv, the team revealed they found three candidate events that might be due to Dark Matter. But two of these were expected to appear anyway because of background noise, the team said, so their results are effectively negative.
Does this rule out the existence of WIMPS? Not necessarily – the team will keep working on their search. Plus, results from a preliminary analysis from11.2 days worth of data, taken during the experiment’s commissioning phase in October and November 2009, already set new upper limits on the interaction rate of WIMPs – the world’s best for WIMP masses below about 80 times the mass of a proton.
And the XENON100 team was optimistic. “These new results reveal the highest sensitivity reported as yet by any dark matter experiment, while placing the strongest constraints on new physics models for particles of dark matter,” the team said in a statement.
