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New Podcast is up at 365 days of Astronomy July 21, 2009

Posted by jcconwell in Astronomy, IYA 2009, moon, Podcast.
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365_iya

A change in the date of our sponserd podcast to TODAY. Link is at:

http://365daysofastronomy.org/2009/07/21/july-21st-astronomy-in-anglo-saxon-england/

Formation of the Elements July 20, 2009

Posted by jmegenhardt in Astronomy, stars, supernova.
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James Megenhard has his blog at:      http://eastrichlandchemistry.wordpress.com/

Stardust, the Building Block of Everything?

At the birth of our universe the only elements formed in any substantial amount was helium and hydrogen.  There were some heavier elements like lithium and beryllium, but these were so minor that they are not even considered.  So where did the carbon that all life is made of, the oxygen that all animals need to breathe, or the iron that makes up some of our strongest buildings come from?  Hydrogen and helium were formed during the Big Bang, while all of the other elements come from small bangs; the death of stars.

At this time, there are 118 known elements.  The simplest element is hydrogen which has only 1 proton and 1 electron.

hydrogen

In order to make hydrogen into another element, protons need to be added; which in turn requires the addition of electrons and neutrons.  For example, add a proton, an electron, and two neutrons, and hydrogen has become helium.

HeliumAtom2

Adding a proton, electron, and two neutrons creates lithium.  Adding yet another proton, electron, and neutron gives beryllium.  By simply adding more protons, electrons, and neutrons, heavier and heavier elements can be formed.  It seems reasonable for helium to form, after all, what else is to be done with the neutrons that hydrogen did not use from the Big Bang?  The question is, why would more protons, neutron, and electrons come together to make any elements past helium?

The Big Bang roughly states that everything that would one day form the physical universe began as a super hot, super condensed mass.  This mass reached a critical point which resulted in the mass exploding.  As the material from this mass cooled hydrogen and helium were formed.  The hydrogen and helium started pooling together into various gas clouds.  These gas clouds were pulled in towards their center, resulting in an increase of mass at center, which created more gravity, which resulted in more hydrogen and helium being pulled in.

In the Center of Star

More mass in center → More gravity in center

↑                                        ↓

More gravity in center ← More mass in center

The increasing density of that material resulted in more gas atoms colliding.  Each time there was a collision, some of that energy was converted to heat.  As more gas was pulled in, there were more collisions resulting in heat increasing, until the temperature reaches around 10 million degrees Kelvin at which point nuclear fusion of hydrogen begins; a star is born.  To sum it up…

More gravity in center → More density in center → More collisions in center → More heat in center until  nuclear fusion is reached.

Nuclear fusion is the process by which two atoms are combined to form a new atom.  When two hydrogen atoms fuse they produces helium and energy.  Click here to see how hydrogen becomes helium. It is the energy produced by nuclear fusion that runs a star.  Since hydrogen is the simplest element with only a proton and electron, the star begins the process of fusion with it, but as hydrogen is used up and temperature increases, the helium produced can undergo nuclear fusion of its own to produce carbon, oxygen, or neon.  Carbon can further fuse to form metals like sodium or magnesium, until nuclear fusion produces iron.

Layers of Fusion in a Star

fusion layers

But why did these elements not form during the Big Bang?  The answer is repulsion.  Hydrogen is a proton and electron, so its formation is easy since opposites attract.  Helium, on the other hand, was a little tougherto form since it needs two positive protons in its center; but like charges repel.  The only reason the two protons in helium did not repel away from each other was the pressure within the expanding material from the Big Bang was higher than the repulsive force.  But this force was not great enough for more than two protons to come together.  The only place in our universe where the force is so great that multiple protons cannot repel from each other is in the heart of a star.

The first 26 elements on the periodic table are formed by stars as they produce energy.  The remaining elements are formed from a star dying.  When a star dies, the gravitational pull upon that star causes the iron center to collapse.  As the center collapses, it reaches a point where the energy build-up causes the collapse to stop and reverse just like a rubber ball will collapse so far before it rebounds.  In other words, the center implodes and then explodes out.  As the center is blown back outwards, it collides with the outer material surrounding the star; which was also being pulled in to the center.  Just like in the birth of a star, this increase of collisions results in even more heat and pressure, which means even more nuclear fusion.  The net result being that as the star is being blown apart, further nuclear fusion is occurring resulting in elements even heavier then iron.  Not only does the stars death form these heavy elements, but it also causes those elements to be blasted out into space, where they can collect and form other astronomical bodies like planets and asteroids.

External resources:

The Universe Adventure

Questia

Think Space

NASA

Yes!! We really did land on the Moon 40 years ago,Today! July 20, 2009

Posted by jcconwell in Astronomy, IYA 2009, moon, Space Craft.
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Forty years ago today Apollo 11 landed on the moon. When I have an open house at the observatory, one of the things people want to know is, can we see the landers that are left on the moon from the Apollo missions. I have to tell them no, too much atmosphere, and not enough telescope.

The scary thing is the 6% of the public who believe the landing was all just one big hoax. Now to answer both questions on the 40th anniversary…we’ve got pictures!!!!

All images credit: NASA/Goddard Space Flight Center/Arizona State University

NASA’s Lunar Reconnaissance Orbiter, or LRO, has returned its first imagery of the Apollo moon landing sites. The pictures show the Apollo missions’ lunar module descent stages sitting on the moon’s surface, as long shadows from a low sun angle make the modules’ locations evident.

The satellite reached lunar orbit June 23 and captured the Apollo sites between July 11 and 15. Though it had been expected that LRO would be able to resolve the remnants of the Apollo mission, these first images came before the spacecraft reached its final mapping orbit. Future LROC images from these sites will have two to three times greater resolution.

Apollo 11 Site, Click for Larger picture

Apollo 11 Site, Click for Larger picture

The Apollo 14 site shows even more detail in the full picture below and the magnified Captions

Apollo 14 Landing Site

Apollo 14 Landing Site

Apollo 14 Site showing foot path and instruments

Apollo 14 Site showing foot path and instruments

These pictures are reminder of a past era of NASA exploration, but the LRO’s mission is paving the way for the future. By returning detailed lunar data, the mission will help NASA identify future landing sites robots and astronauts, locate potential resources,like water, and measure the moon’s radiation environment while testing new technologies.

NASA Gravity Probe B July 19, 2009

Posted by neogajrhscience in Astronomy, General Relativity, Space Craft.
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Amy Brown has her blog at: http://neogajrhscience.wordpress.com/

Gravity Probe B measuring geodetic and frame shifting effects

What is Gravity Probe B?

Gravity probe B is a NASA mission first proposed in 1959 that was launched into space April 20, 2004. The probe contained a very accurate tracking telescope, and 4 gyroscopes. Its purpose was to test Einstein’s general theory of relativity, by measuring the amount of warp Earth causes in its surrounding spacetime (the geodetic effect) and the amount that Earth drags its local spacetime along as it rotates (the frame dragging effect). Data collection from the probe was completed in August, 2005, and data analysis has continued to the current date.

History of the Gravity Probe B Mission

Albert Einstein proposed his theory of general relativity in 1916, which linked the concepts of geometry and time with gravity.  Gravity, as we understood it from Isaac Newton, was an attractive force between bodies due to their mass.  Einstein proposed that, instead, gravity was a manifestation of the warping of spacetime around a body, which is also related to the body’s mass.  To visualize this warping of spacetime, imagine a bowling ball placed in the center of the fabric of a trampoline.  The mass of the bowling ball will pull the fabric down, warping the fabric in three dimensions.  The bowling ball, of course, is compared to any object in space, and the more massive the object, the greater the warp.

Warping of spacetime

Warping of spacetime

General relativity has stood up to several types of tests.  One of these involves the observational evidence of the precession of the perihelion of mercury, which shifts at the rate of 43 arc seconds per century.  After all other influencing factors have been accounted for, this shift is attibutable to the effect of general relativity from the mass of the sun.  Another type of test shows that light from distant objects bends as it travels past massive objects, such as the sun.  This has been measured both with visible light, and more accurately with radio waves. Gravitaional redshift is another method that has supported general relativity.  This measures the energy and time difference in objects at different positions in relation to earth.  GPS satellites must account for the difference in 38 microseconds per day from the height they are orbiting to the surface of the earth.  While these and other tests have provided substantial evidence to support general relativity, the evidence is not as precise as physicists would like it to be.  Scientists were striving to devise a way to test general relativity on a precision basis.

In 1959, Stanford Physics Departmment Chair Leonard Schiff and MITphysicist George Pugh both independently proposed testing general relativity using gyroscopes.  Schiff went forward with the idea, bringing on board other Stanford professores William Little, William Fairbank, and Robert Cannon.  Schiff, Fairbank and Cannon continued to research the idea from different angles, and this research led to a proposal to NASA in 1962.  NASA adopted the Gravity Probe project  in 1964, and Stanford remained the primary project base.

The concept of the Gravity Probe B

The concept of the Gravity Probe B

The idea behind Gravity Probe B was to construct a space probe containing gyroscopes aligned to a distant space object.  The spacecraft would surroound the gyroscopes, allowing them to remain in freefall.  As the spacecraft orbits the earth, any warping effect of the spacetime around the earth would cause a measurable orientation shift of the spinning gyroscopes.  This was to be measured in regard to two effects:  the geodetic effect, which is the simple warping of spacetime due to the earth’s mass, and the frame shifting effect, which is the effect caused by earth dragging spacetime along as it rotates.

The idea of the probe was a simple one, but the technology required was not.  More than a dozen new technologies had to be developed to make the probe work, and this took over 30 years to accomplish.  The spheres that make up the four gyroscopes hold a guiness world record as the roundest objects ever made, and required the invention of new manufacturing techniques to complete them.  They are made of quartz, refined to be homogeneous to within two parts in a million, and the sphericity is accurate to within 3 ten millionths of an inch. The spheres are coated with superconducting niobium.

Rotors

Gyroscope rotors, without and with niobium coating
Gyroscope rotors, without and with niobium coating

The gyroscopes are housed within a suspension system that is only 32 microns larger in radius than each gyroscope. Also attached to the housing is a SQUID magnetometer, which measures the tilt of the gyroscope spinning within as its magnetic field interacts with the sensor.  The satellite itself contains a nine foot long dewar (a large thermos) to contain the superchilled helium necessary to maintain the correct temperature to have the superconductive gyroscopes work properly.

Dewar

Dewar

In order to combat the small amount of heat that would enter the dewar, a special plug had to be designed to allow helium condensate to seep out into the outer layer.
In the late 1970’s and early 1980’s, the probe underwent a changeover form a research project to a flight mission project.  Lockheed Martin was brought in to help with the design.  It wasn’t until the late 1990’s, however, that the project was brought directly to NASA as a definite flight program.  It took nearly seven years to work out all the bugs.  Gravity Probe B was launched into orbit on April 20, 2004.

Launch of spacecraft

Launch of spacecraft

The Mission

In a nutshell, the spacecraft that took over thirty years to design and launch was going to test the general theory of relativity.  The spacecraft contains a tracking telescope.  This telescope is pointed at a distant star, IM Pegasi, as a guide star. A quasar would be the desirable tracking object, but the telescope would not be able to stay focused on one, so IM Pegasi was used, and its position would then be compared to a distant quasar during data analysis.  Once the telescope locks onto the position of the guide star, the gyroscopes are caused to sart spinning, and their alignment is matched to the alignmnet of the telescope. As the gyroscopes continue to spin, and the spacecraft orbits the earth, electrical signals between the gyroscopes and sensors in their housings are measured and sent back ot earth as raw data.

After the succesful launch, Gravity Probe B was in orbit 642km above the Earth.  Before the probe could begin collecting data, a four month period of initialization and check out was accomplished.  This period was supposed to be shorter, but several problems had to be corrected or accounted for before data collection could begin.  One problem was that the spacecraft had trouble tracking the starfield due to the roll of the craft. Another problem was the loss of two of the sixteen helium thrusters.  Setting the gyroscopes to spinning and aligning their spin axes with the guide star also caused some delay.  The gyroscopes were expected to spin at a faster rate than they actually were spinning, so many adjustments and calculations had to be made on the ground to achieve alignment.  One further delay during initialization occured whern the probe passed over the Earth’s south pole, and was bombarded by proton radiation from the sun.  The delay was caused by one of the spacecraft’s computers going down and having to be rebooted after the proton bombardment.  Because the initialization phase took quite a bit longer than anticipated, the decision was made to allow the data colection phase to be shortened.  The spacecraft continued to send data until August 15, 2005. The remaining six weeks until the helium was depleted and the mission was ended on September 29, 2005 were spent claibrating and testing the equipment on the spacecraft.

Data Analysis

Scientists associated with the Gravity Probe B mission have been analyzing the data since 2005.  In the ideal scenario, every instrument on the spacecraft would have performed without complication, and staightforward data  would have been provided.  Some of the systems on the probe functioned very well.  The dewar and the telescope performed exactly as expected.  Unfortunately, the gyroscopes did not.  The spheres themselves did spin extremely predictably, but the magnetic fields that they produced as they did so have been difficult to analyze.  The spin axes of the gyroscopes were effected by the torque of the spacecraft, and scientists have been trying to account for the data anamolies by identifying and quantifying them.  In terms of the two phases of data, the geodetic effect jumped out obviously, even from the raw data.  The measurement of the warping of space around earth was calculated by the data to be within 1% of the predicted 6606 milliarcseconds/year.   It is the measurement of the frame-shifting, however that is more effected by the data problems.  NASA has closed the project, but other funding sources are allowing the data analysis to continue.  Scientists with the project predict that with further analysis, they will be able to get the frame shifting data to within 3 to 5 percent of the expected 39 milliarcseconds per year.

The Legacy of Gravity Probe B

Regardless of the scientific outcome of the Gravity probe itself, the thirty year life of this research and space flight mission has provided the world with valuable benefits.  Ninety seven students received PhDs at Stanford and other universities working on this  project.  Technologies developed for the spacecraft have been used in other applications, such as the optical bonding and fused quartz technologies used on the gyroscopes.  Photo diode detector technology has helped to improve digital cameras for all of us.  The porous helium plug developed for Gravity Probe G has been used in other cryogenically sensitive missions such as IRAS and COBE.  Further, the attitude control technology in the spacecraft led to more accurate (1 centimeter) GPS now being used for automatic aircraft landing and automatic precision farming.  Scientists and teams associated with Gravity Probe B have won several awards, including the 2005 NASA group achievemnet award given to the whole team.  Gravity Probe B will remain into the future as one of the most memorable NASA missions in the history of the space program.

Further Information

The information contained in this article was obtained form the following sources:

http://einstein.stanford.edu/

http://www.nasa.gov/mission_pages/gpb/index.html

http://en.wikipedia.org/wiki/Gravity_Probe_B

Good bye Walter…. July 18, 2009

Posted by jcconwell in Astronomers, Astronomy, Space Craft.
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Legendary CBS news anchor Walter Cronkite, died June 17, 2009. Even though he hasn’t sat in the anchor chair for more than a quarter of a century, the impact on both journalism and the space program is felt even today.

Both objective and passionate, Walter Cronkite, personified the best in reporting, but especially science reporting. In my opinion he was as reponsible for making more scientist of my generation,  than any person. And “That’s the way it is”

Wow… those are some big telescopes! July 18, 2009

Posted by pjhsci in Astronomy, Observatory, telescopes.
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Matthew Sanders has his blog at:   http://pjhsci.wordpress.com/

You know, most people think that the Hubble Space Telescope with its 2.4 meter mirror is the best window into the universe because it resides in orbit, has no atmosphere to mess with the view, and above all, it is almost always the only telescope that you hear about through regular media venues.  This will change within the decade.  There is a new breed of telescopes that are Earth-based that can deliver images ten times sharper than Hubble is capable of.  In the works are reflectors that will provide images up to 100 times sharper than that!

How we adjust for our shortcomings, being here on Earth and all…

Most of the largest scopes today use reflectors measuring 8-10 meters across that may be segmented into many smaller mirrors such as the Keck system of Hawaii.  Keck II Mirror showing segmentationThese scopes benefit not only from the fact that the mirrors can gather a large amount of light, but also the use of adaptive optics systems. (The AO system in the photo of Keck II is at the top of the photo partially housed on the frame skeleton along the right-hand side.)  These systems are what allow Earth-based telescopes to compensate for one of the plagues of astronomers on Earth:  the atmosphere,  more specifically, the turbulence within the atmosphere.  That turbulence is what makes the stars appear to twinkle.  AO systems reduce, if not eliminate, most of that issue.  The simplified version of how AO systems is rather neat.  A laser is fired from the telescope into a thin layer of sodium atoms that exists in the atmosphere, causing them to glow.  This glow is monitored by the AO system to adjust for the atmospheric interference more than 1000 times per second.  This technology turns distant stars from pretty, fuzzy-edged smears to clear, tiny points of light.  Without AO, astronomers could differentiate between objects that were 1/3600th (1 arc second) of a degree apart.  Now, using AO on current scopes like Keck, astronomers can identify multiple objects within that single arc second!

Wait, only an 8.4 meter mirror?  What is so special about that?!

Courtesy www.lsst.org/News/ 0501/050111.shtml
The LSST will provide a generous field of view to explore. Courtesy http://www.lsst.org/News/ 0501/050111.shtml

In August of 2008, under the football stadium at the University of Arizona, a spinning furnace cast the 8.4 meter mirror that is going to be the eye of the Large Synoptic Survey Telescope.  The LSST will be unique, not in the size of the mirror, but in the field of view it should provide.  Conventional scopes have a field of view of around 0.5° per side.  The LSST will provide astronomers a field of view that is 10° per side.  That means that the LSST can take images of the entire visible night sky over the course of a few days rather than months or years.  It will be located on a mountaintop in Cerro Pachón, Chile.  This will allow astronomers to observe objects and events at distances over 10 billion light years!  The ability to record the entire sky repeatedly and quickly will give astronomers the chance to build a motion picture of sorts of short-term events that are missed using conventional telescopes.  Over the course of many cycles, new near-Earth asteroids could be located, flares on dim stars could be identified, and perhaps some of the mysteries of dark matter and energy could be brought into clearer focus.  Innovative telescopes like the LSST could be the key to unlocking those riddles that drive astrophysicists bonkers with uncertainty.

Okay, how big are we talking here?

If one 8.4 meter mirror is good, why not use two?  The Large Binocular telescope on Mt. Graham in Arizona boasts two 8.4 meter mirrors that produce an effective light gathering ability of an 11.8 meter telescope.  With some of the new adaptive optics enhancements coming down the pipe, it is hoped that the LBT will have the effective ability of a 23 meter scope in a smaller package.
If one 8.4 meter mirror is good, why not use two? The Large Binocular telescope on Mt. Graham in Arizona boasts two 8.4 meter mirrors that produce an effective light gathering ability of an 11.8 meter telescope. With some of the new adaptive optics enhancements coming down the pipe, it is hoped that the LBT will have the effective ability of a 23 meter scope in a much smaller package.

There are two schools of thought on this matter:  single reflector or multiple reflectors.  The Large Binocular Telescope in Arizona uses a tandem mirror (Keck I and Keck II can be used in tandem, as well) to provide an image greater than the sum of its parts. (see sidebar)  These arrangements can be constructed in smaller spaces where area is at a premium.  A tandem system takes images from both mirrors and uses computer programs to combine the images, adjusts them with the AO system and produces a composite image.  Other multiple reflector systems are on the slate as well.  In 2018, it is projected that the Giant Magellan Telescope will be functional in Chile.  This composite telescope will utilize not two, but seven 8.4 meter mirrors to produce an image!  The Very Large Telescope array will use a total of eight reflecting units when fully operational.  There will be four 8.2 meter stationary units and four 1.8 meter moveable units to compile images.

This is really interesting technology, but really, just how large a single reflector telescope are astronomers trying to construct?  The Thirty Meter Telescope is to be located in either Chile or Hawaii and scheduled to be online in 2018, but that is small potatoes compared to another monster slated for 2018.

This image portrays the proposed European Extremely Large Telescope with its 42 meter reflector.  This giant is actually a scaled down version of the budget-crippled Overwhelmingly Large Telescope that was to utilize a 100 meter reflector!
This image portrays the proposed European Extremely Large Telescope with its 42 meter reflector. This leviathan is actually a scaled down version of the budget-crippled Overwhelmingly Large Telescope that was to utilize a 100 meter reflector!

The Extremely Large Telescope is just that; an extremely large telescope!  This 5500-ton reflector system will be housed in an observatory 80 meters tall and 100 meters in diameter.  The mirror will be a staggering 42 meters across… yes, 42 meters! Imagine the distance that our puny human optics will be able to penetrate into space with this behemoth as our tool!  What new worlds could we discover?  What origins of the universe could we unveil?  Just imagine what we will be able to see…

LBT Photo – www.kosmologs.de/
ELT Photo – www.spacedaily.com/

Information gathered from:

National Geographic, June 2009

European Space Organization

Bill Arnett’s Nine Planets.org

Tunguska…The Mystery Continues July 17, 2009

Posted by sgoebel in Asteroid, Astronomy.
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Shannon Goebel has her blog at:    http://mrsgoebel.wordpress.com/

As the saying goes, everyone loves a good mystery and the 1908 Tunguska Event does not disappoint.  I have long been fascinated by this story and love to discuss it each year with my Earth Science students.  However, just as in my classroom before we can delve into the juicy details and “who-dun-it’s”, we must first explore the history surrounding this event.

When? Where?

It was a quiet morning around seven o’clock on June 30, 1908 (June 17, 1908 according to the Julian Calendar which was in local use at the time)  in remote Siberia near the Podkamennaya Tunguska River.  The day started just like any other; no one would have predicted that it would forever be recorded and remembered for the unique and literally Earth-shattering event that would take place.   One of the first questions that probably comes to your mind, is where exactly is this place?  Shown on the map below, the Tunguska River is located in what is known today as the Krasnoyarsk Krai in Russia.

Photo taken from www.science.nasa.gov

Photo taken from www.science.nasa.gov

What?

For this portion of our investigation, we should begin with the basics upon which most scientists currently agree.  According to Don Yeomans, manager of the Near-Earth Object Office at NASA’s Jet Propulsion Laboratory, “It is the only entry of a large meteoroid we have in the modern era with first-hand accounts.”  The impact is believed to have been caused by the air burst caused by a large space rock (the true identity of which will be discussed soon), at an altitude of 5-10 kilometers (or for those meterically challenged people, 3-6 miles) above the Earth’s surface.
One major factor in this mystery is that the first scientific expedition to the area did not take place until 19 years after the event. In 1921 the first expedition to the area led by Leonid Kulik, the chief curator for the meteorite collection of the St. Petersburg museumset out but was cut short to due to the extremely harsh conditions of the area.  However six years later, a second expedition, again lead by Kulik, reached its goal.
Photo taken by Professor Leonid Kulik on his 1927 expedition to the impact site.
Photo taken by Professor Leonid Kulik on his 1927 expedition to the impact site.

While on their investigation, the crew collected numerous eyewitness testimonies like the one given below by S. Semenov.

“At breakfast time I was sitting by the house at Vanavara Trading Post (65 kilometres/40 miles south of the explosion), facing north. […] I suddenly saw that directly to the north, over Onkoul’s Tunguska Road, the sky split in two and fire appeared high and wide over the forest (as Semenov showed, about 50 degrees up – expedition note). The split in the sky grew larger, and the entire northern side was covered with fire. At that moment I became so hot that I couldn’t bear it, as if my shirt was on fire; from the northern side, where the fire was, came strong heat. I wanted to tear off my shirt and throw it down, but then the sky shut closed, and a strong thump sounded, and I was thrown a few yards. I lost my senses for a moment, but then my wife ran out and led me to the house. After that such noise came, as if rocks were falling or cannons were firing, the earth shook, and when I was on the ground, I pressed my head down, fearing rocks would smash it. When the sky opened up, hot wind raced between the houses, like from cannons, which left traces in the ground like pathways, and it damaged some crops. Later we saw that many windows were shattered, and in the barn a part of the iron lock snapped.”

But what exactly was this so-called “space rock”?  That is what scientists are still debating 100 years later!  Information given on NASA’s website states the following.It is estimated the asteroid entered Earth’s atmosphere traveling at a speed of about 33,500 miles per hour. During its quick plunge, the 220-million-pound space rock heated the air surrounding it to 44,500 degrees Fahrenheit. At 7:17 a.m. (local Siberia time), at a height of about 28,000 feet, the combination of pressure and heat caused the asteroid to fragment and annihilate itself, producing a fireball and releasing energy equivalent to about 185 Hiroshima bombs.”
However, a recent article published by Kelley, Seyler, and Larsen brings new light to this subject.  This group of researchers suggest that instead of meteorite being responsible for this impact, perhaps a comet is to blame.  Their hypothesis is based upon data collected from space shuttle launches that took place almost 100 years after the Tunguska Event.  “The research, accepted for publication (June 24, 2009) by the journal Geophysical Research Letters, published by the American Geophysical Union, connects the two events by what followed each about a day later: brilliant, night-visible clouds, or noctilucent clouds, that are made up of ice particles and only form at very high altitudes and in extremely cold temperatures.” (www.sciencedaily.com/releases/2009/06/090624152941.htm)
So, what is really to blame for this mysterious impact?  Well, I guess that I will leave that up to you and your research to decide!  Regardless of which side you choose, this is an amazing so far one of a kind event for us to study.  Perhaps what we learn can help prepare us for other Near Earth Objects that are headed our way in the future.  Happy hunting!
References & Useful Links for More Information:
http://science.nasa.gov/headlines/y2008/30jun_tunguska.htm
http://www.sciencedaily.com/releases/2008/07/080715103956.htm
http://www.sciencedaily.com/releases/2009/06/090624152941.htm
http://en.wikipedia.org/wiki/Tunguska_event

Weirdest Object in the Solar System? July 16, 2009

Posted by stcescience in Astronomy, planets.
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Matt Bulman has his blog at:    http://stcescience.wordpress.com/

Taken From newscientist.com

Astronomers have recently discovered one of the strangest objects, to date, in our solar system.  This dwarf planet has virtually the same diameter as Pluto but is only about 1/3 its mass – meaning it actually looks more like a flattened cigar or pancake.  Read more at:  http://www.space.com/news/080919-fifth-dwarf-planet.html

The question then becomes how does such an object form?  It is no coincidence that nearly all planets and stars are spherical in shape.  Objects tend to assimilate to the lowest energy state possible, or in the case of celestial bodies – spheres.  This is because the planets and stars have a very large gravitation force pulling inward from all directions; creating a “ceiling” or “roof” that is the same height in all directions (a sphere).  But how then do anomalies such as these exist?

According to the article “The new dwarf planet has the same diameter as Pluto, but is much thinner, and contains about 32 percent of Pluto’s mass. Scientists suggest Haumea’s long, narrow shape arose from its rapid spin — it rotates about once every four hours.”  In other words there are forces on this object other than just its gravitational pull.  This is true of all celestial bodies; however it becomes much more apparent as objects begin to rotate very quickly.

Think of it much like building a clay pot.  As you rapidly spin the clay in a circle the clay begins to flatten and elongate.  This is due to the centripetal acceleration of the mass.  As the mass continues to spin faster and faster it begins to accelerate outward and is either shot outward and off the remaining mass or causes the clay pot to elongate and squish together.

Haumea’s formation would be much like that of a clay pot.  While the dwarf planet has a gravitational force pulling inward in all directions, it is also spinning incredibly fast on its axis.  So you could imagine that the mass is being pulled in and pushed out by two competing forces.  However this gives rise to an even bigger question – why then is such a large body spinning so incredibly fast?

What’s even more interesting is the object’s name.  According to the original article, “The object previously known as 2003 EL61 is now named Haumea, after the goddess of childbirth and fertility in Hawaiian mythology.”

Taken from: NASA, ESA, and A. Feild (STScI)

Haumea is one of the largest members of the relatively newly coined “Kuiper Belt”.  The Kuiper Belt is basically a large gathering of ice structures extending out further than Neptune’s orbit.  Through the analysis of this region in space astronomers have pretty much been able to demote Pluto from full planet to simply the largest member of this region in space.  It is a lot like the asteroid belt only it is much larger and all of the substances are made primarily of ice rather than rock.  Astronomers are discovering more and more Kuiper Belt members through closer analysis of our solar system.

Institute for Astronomy at the University of Hawaii faculty member David Jewitt is one such astronomer.  Jewitt believes, “the Kuiper Belt holds significance for the study of the planetary system on at least two levels. First, it is likely that the Kuiper Belt objects are extremely primitive remnants from the early accretional phases of the solar system. The inner, dense parts of the pre-planetary disk condensed into the major planets, probably within a few millions to tens of millions of years. The outer parts were less dense, and accretion progressed slowly. Evidently, a great many small objects were formed. Second, it is widely believed that the Kuiper Belt is the source of the short-period comets. It acts as a reservoir for these bodies in the same way that the Oort Cloud acts as a reservoir for the long-period comets.”

Women who broke the barriers….. July 15, 2009

Posted by dhsscienceteacher in Astronomers, Astronomy.
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Mellisa Ray has her blog at http://dhsscienceteacher.wordpress.com/ and is my long suffering Graduate assistant this summer.

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Einstein, Newton, Kepler…. these are astronomers whom every high school student knows. However, I remember wondering in high school, “Where are the women scientists?”  Whether it be in the grade school or the university level, I believe every science teacher should know of more scientists than Einstein, Newton and Kepler. Perhaps the astronomers I will discuss are more obscure than Newton, but discussing them might inspire a young girl to choose a different career path. Although this list is short; these are a few of my favorite great women.

Hypatia of Alexandra was born between 350 and 370 AD. A woman in a land of very few options, she rose to be considered the first notable woman in mathematics. Her father was her teacher while living in Roman Egypt. It is thought she wrote on astronomy, mathematics, and philosophy. She may have invented the plane astrolabe, the graduated brass hydrometer, and the hydroscope. The plane astrolabe would be used to estimate time given a known star’s altitude. A hydrometer would be used to find density, and the hydroscope would be used to see under water. She was a very unusual woman during her time often acting like a man in a time when men and women held very separate roles. It is believed she angered an influential bishop at the time who convinced others to dislike her. In the year 415 AD, she was killed by a Christian mob. Although it is unknown for sure, it has been said she was flayed and burned. Very little is know about her since much of her work was destroyed in a fire.

Annie Jump Cannon was born in 1863.  She was a Wellesley graduate for her undergraduate and graduate studies. She worked for Professor Whiting learning spectroscopy at Wellesley. After graduation, she was hired by Harvard to work as a “computer” along with a number of othe women making very little money. She found the spectral sequence of different stars eventually helping come up with OBAFGKM. She published nice volume of Henry Draper Catalog and the Henry Draper Extension. She was appointed professor at Harvard two years before her retirement. Cannon classified close to 300,000 stars in her lifetime. She also classified five nova and approximately 300 long-period variable stars.

Cecilia Payne-Gaposchkin was born in 1900. She completed her studies at Cambridge but was not awarded a degree because women did not receive degrees at the time. She eventually traveled to Harvard to work with Harlow Shipley. By 1923, she was ready to present her thesis to Radcliffe College. Her dissertation is considered one of the best ever in astronomy. In her thesis, she calculated a temperature scale to go with the classification system. Due to her theory of what stars are composed of, she discussed the Sun being made almost completely of hydrogen. Although she was correct, she did not make a definite conclusion as many believed at the time that the Sun was made of the same main elements as our planet.  She stayed at Harvard for career only briefly thinking of leaving because of her lack of title. Eventually she was named chair of the department.

Jocelyn Bell Burnell was born in 1943. While at Cambridge, she helped her advisor, Antony Hewish, to create a telescope for their research needs. It was an extremely large radio telescope. She analyzed long pages of lines to try to find differences. She did find a difference in the lines, leading to the discovery of pulsars while she was working on her Ph.D. at Cambridge University in 1967. She received her Ph.D. in radio astronomy in 1968. Eventually, Martin Ryle and Hewish provided the theoretical information about pulsars and received the Nobel Prize for it; however, Burnell was left out of the award. After graduating, she continued her love of astronomy by seaching the night sky throughout her career while working at a number of universities in the United Kingdom.

Websites:

http://www.wellesley.edu/Astronomy/Annie/

http://www.sdsc.edu/ScienceWomen/cannon.html

http://www.distinguishedwomen.com/biographies/cannon.

http://womenshistory.about.com/od/hypati1/a/hypatia.htm

http://en.wikipedia.org/wiki/Hypatia_of_Alexandria ,

http://starchild.gsfc.nasa.gov/docs/StarChild/whos_who_level2/bell.html

http://www.scientificamerican.com/slideshow.cfm?id=10-nobel-snubs&thumbs=horizontal&photo_id=D2B78179-CAD3-E707-DB0C8A010B583A87

http://cwp.library.ucla.edu/Phase2/Payne-Gaposchkin,_Cecilia_Helena@861234567.html

http://www.harvardsquarelibrary.org/unitarians/payne2.html

Solar Flares – What, effects, and the end of the world…? July 14, 2009

Posted by dgsphysics in Astronomy, Solar and Space weather.
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Steve Zownorega has his blog at:         http://dgsphysics.wordpress.com/

What They Are:

Solar flares are an amazing phenomenon in astronomy. Originating from a star, the solar flare has some interesting properties that can make a strong connection to physics as well as make you wonder if we will survive the year of 2012.

solar flare magneticA solar flare occurring on the sun. Notice the magnetic field lines that are emerging from the surface.

A solar flare originates within the sun, and is caused by a build up of magnetic energy. When this magnetic energy (stored in a magnetic field) is released, a large amount of plasma is fired from the surface, usually directly over a sun spot. This magnetic field energy is transferred into many different types of energy, one of which is stored in waves (Gamma rays, x-rays, AKA Solar radiation). The amount of this energy that is in a typical solar flare is equivalent to millions of 100-megaton hydrogen bombs going off at the same time. Hard to wrap your head around that? That is about 10^20 joules per second. Still wondering what that is? It would be like having 1,600,000,000,000,000,000 (1.6 quintillion) light bulbs all on at the same time. It seems like a lot of energy, but this solar flare has less energy than the actual amount of energy that the sun creates during its fusion reaction. Just think of a solar flare as a ‘burst’ of this energy.

Effects:

So with all of this energy being released, why doesn’t it effect us on earth? Well thanks to the earths atmosphere, we never get hit directly with this solar radiation. The atmosphere will deflects most of the electromagnetic radiation. However, NASA has major concerns with these solar flares due to the fact that anything outside of the atmosphere such as satellites, space crafts, and even astronauts can be effected by this mass amount of energy.

Satellites and space crafts do have to be worried about a solar flare. These electromagnetic waves (gamma/x-rays) can burn out circuitry causing many systematic failures. This is a very similar situation to an EMP (electromagnetic pulse) that is used in destroying all electronic devices. With that, any electronic device sent out into space has a fail safe system which can be controlled to protect circuitry and draw large currents away from the main components in the device.

On that note, solar flares have a capability of effecting human beings. NASA is currently running a test on an artificial human being with an artificial solar flare. The reason for this test is to understand what type of safety systems we might have to give astronauts if we travel to the Moon or Mars. In this test, they will emulate what a solar flare would do to a person by having short exposures of radiation strikes to a plastic torso. This torso will have all the elements of a human by scientists placing blood in tubes and within organs through out the body. They also want to run a test where they expose this torso to 18 months (about as long as a mars mission might last) of normal radiation from the sun. Results are still pending, keep a watch on this website:

Phantom Torso

End of the World….?

You might ask yourself after reading this: When am I ever going to be effected by a solar flare? Well it may soon come. Records have indicated that in 1859 a large amount of solar radiation rained down on the earth. Richard Carrington, an English astronomer at this time, was observing sun spots when all of a sudden a bright white flash appeared on a piece of the sun for about 5 minutes. The northern lights, a common solar event that resembles this solar radiation coming down to earth, was the brightest ever recorded during this time in 1859. In 1859 journal entries through out the US (commonly seen only by the north pole) as well as many captains logs across many different oceans have indicated seeing a green glow so luminous that they could read the newspaper at 1:00AM. This is one of the largest northern light activity ever shown, and it was due to this large eruption in the sun.

A image of the northern lights

During this beauty came many other effects. One that came with the 1859 solar activity was technological problems. The telegraph system, the communication device at that time, went out of service for about 14 hours. Also, many measurement devices were also effected by having readings that were off the charts. This is due to the major effect that electromagnetic waves can have on electronic devices, which you can get more information here.

So you might be asking yourself why this concerns you? We live under the umbrella of technology. Power grids, information, communication, and basically any other part of technology could be effected by an event of this magnitude. Satellites alone in space might be greatly damaged, if not destroyed, by the solar energy.We have invested upwards to 60 billion dollars in these satellites – and these are the exact ones that help us communicate, receive and send information, and go about our daily life.

Your next question might be when will this happen again? It is estimated that something of this magnitude happens once every 500 years. An event of half of this magnitude happens once every 50 years. And the last one recorded was in 1960 – so one is on deck to happen within the next few years.

On that note, we can investigate one of the more interesting ideas that has been proposed. The Mayan’s predicted that the world is to end in 2012. One of the predictions is that it would be done by a large amount of solar activity. Now, solar flares are known to originate from sun spots, and currently there are no sun spots. Sun spot activity follows a cycle of 11 years, and we are about to enter the new cycle of sun spots. This may describe why we get these major events as described in 1859, however, I do want to remind everyone that the magnetic field (our atmosphere) of the earth is what protects us from this solar radiation. So to make a claim that we would die from solar radiation would be false.

So to give you a little recap:

I would like to leave you with a thought. Y2K was thought of as being the end of man kind, and this was due to technology. Many people were frightened due to…..yes, if you remember, it was due to a date change. Comparing Y2K to a solar flare, I just want to say that a solar flare (not properly prepared for) can do a lot more damage than a single date change.