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CURIOSITY TOUCHDOWN 10:31PM PDT (12:31AM CDT) TONIGHT!!! August 5, 2012

Posted by jcconwell in Astronomy, planets, Space Craft.
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TONIGHT the largest rover ever to land on a planet will enter Mar’s astmosphere! Curiosity is over 5 times bigger than the previous Mar’s rover. To get the details of what is refereed to the “7 minutes of terror” , which is what the scientists call the time it takes to enter the Martian atmosphere and land, click on the NASA video below. Since Mars is 154,000,000 miles away it takes a light or radio signal 14 minutes to reach Earth. So the landing is totally controlled by the on-board computer reading the  sensors, and then adjusting the course. For the scientists waiting on Earth who have spent a good part of a decade on this mission, it will be closer to 7+14=21 minutes of terror, before they know if it is a success or a failure.

There will be a GOOGLE+ hangout event sponsored by Universe Today at http://goo.gl/a5t4O

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Volcanism on Icy Io July 20, 2012

Posted by epscienceblog in Astronomy, moon, Solar and Space weather.
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Io, the closest moon to Jupiter, has an orange-brown
surface containing sulfur, the light areas are an icy
mix of sulfur and the dark areas highlight volcanic areas. Composite picture from NASA

As we have studied the Universe, one of the main ways that we have learned in the past is by using the Earth as a comparison, using all that we know about our planet as a reference for the other galactic bodies that we explore.  What is amazing now is the shift that is taking place, where we are beginning to use what we learn about other celestial bodies and apply that information to our own planet.  We learn even more about Earth as advances are being made in the exploration of our universe.  One example of how we are applying our knowledge of other bodies is Io.  The new information that is being gained from Io gives clues to the processes that occurred on Earth when it was young.

Io is an icy satellite of Jupiter 628,866,000 km from Earth, far enough from the sun that its surface temperature is 175 K (-143°C or -230°F) and is covered in sulfur dioxide frost.  Io’s yellow tinged crust is not fractured, therefore, it is not thought to have tectonic activity.  Despite these two factors, Io has the most volcanic activity in our solar system, spewing out over 100 times as much lava as all Earth’s volcanoes combined and may have as many as 300 active volcanoes.

Image from New Horizons, highlighting the Tvashtar volcanic plume reaching 300 km above the horizon.
Credit: NASA

The surface of Io is much different than previous expectations had dictated, and contains potential clues to the history of Earth.  When the Voyager spacecraft missions took images of Io in1979, NASA was surprised to see that Io was not full of craters, as had previously been thought.  It was assumed that Io would be cratered much like our moon.  Yet Io hardly had any craters at all, instead it had irregular pits and blotches of color.  When the images were carefully examined, volcanic plumes and lava flows were discovered.  Infrared spectrometry also detected abundant sulfur and sulfur dioxide in the volcanic plumes.

The sulfur on Io’s cold crust is solid, though when heated inside the crust, it explodes much like steam in a geyser on Earth.  The sulfur cools as it is ejected and may fall back down as “snow” on Io’s surface.  The lava flows on Io can range in color from orange to red to black and are found around the active vents.  The Galileo spacecraft monitored volcanic areas in the late 90s and found that the active lava flows of Io were between 1700 to 2000 K (around 1450 to 1750°C, or 2600 to 3150°F).  Earth’s lava temperatures are around 1300 to 1450 K.  The lava on Io is probably ultramafic, containing magnesium and iron that have higher melting points.  Ultramafic lava is found on Earth, but was formed when the Earth was young and the interior was much hotter than today.

A blue-tinged volcanic eruption forcing out rock and sulfurous gas,
taken from the NASA Galileo spacecraft.

The volcanoes on Io are mostly caldera-like, containing  large pools of lava, though some are fissures or cracks where the molten material can flow over the surface.  Loki Patera is a caldera with a diameter of 200 km, which makes it the largest in the solar system.  Some of the volcanoes form fountains, umbrella-shaped flows that spread up and out over large distances.  The Prometheus plume is a volcanic region that has been seen in almost every image taken of Io from 1979 to 1997, suggesting that it has been continually erupting for years.

Jupiter’s four largest moons (from left to right: Io, Europa, Ganymede, Callisto)
with sizes to scale. Credit: NASA

Aside from the similarities, we can also learn from the stark differences between Earth and Io.  While the heat in Earth’s core is mainly due to the radioactive decay of uranium, thorium and potassium, Io’s extreme internal temperature is caused by gravity.  Io is the closest natural satellite to Jupiter and is one of Jupiter’s four largest moons.  Due to the close proximity to Jupiter and the slightly elliptical orbit of Io, the gravitational pull on Io ebbs and flows, creating contraction and expansion on Io’s crust.  The next two moons closest to Io, Europa and Ganymede, also interact gravitationally with Io and increase the forces on Io as they routinely pass by.  The speed of the moon’s orbits are not the same; during the same period of time Ganymede orbits once, Europa orbits twice and Io orbits four times around Jupiter.  The differences in the orbits cause the moons to line up often.  This increases the gravitational pull on Io from both Europa and Ganymede as well as from Jupiter.  This continual pull creates tidal heating causing temperatures that melt the rock within Io and fuels the intense volcanic activity.  The process of squeezing and flexing is similar to how a ball of clay will soften and warm as a person kneads it.  However, the heating of Io is unlike what we have ever experienced on Earth.  The tidal heating on Io adds as much energy as 24 tons of TNT exploding every second.  Io’s surface receives 2.5 watts of power to each square meter, compared to 0.06 watts per square meter on the Earth’s crust from global heating.  The only areas on Earth that are comparable to Io’s average are in Earth’s volcanic areas.

TRANSIT OF VENUS TODAY June 5, 2012

Posted by jcconwell in Astronomy, planets, Solar and Space weather, Sun.
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Come to the Charleston public library to view the transit of Venus. From 4:30pm to 6:00PM TODAY!!

Image

Astronomy Colloquium: COSMIC COLLISIONS February 22, 2010

Posted by jcconwell in Astronomy, meteor, planets.
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Dr Heidi Hammel

COSMIC COLLISIONS

Dr. Heidi Hammel

Professor of Physics and Astronomy , Space Science Institute

Thursday,  February 25, 4:00PM

Physical Science Building , Room 2120

Sponsored by the College of Sciences in coordination with WISM (Women in Science + Mathematics at EIU)

Dr. Hammel received her undergraduate degree from the Massachusetts Institute of Technology (MIT) in 1982 and her Ph.D. in physics and astronomy from the University of Hawaii in 1988. After a post-doctoral position at NASA’s Jet Propulsion Laboratory, Pasadena, Calif., Hammel returned to MIT, where she spent nearly nine years as a Principal Research Scientist in the Department of Earth, Atmospheric, and Planetary Sciences.

Dr. Hammel primarily studies the outer planets and their satellites, focusing on observational techniques. She was a member of the Imaging Science Team for the Voyager 2 encounter with the planet Neptune in 1989. In 1994, she led the team that investigated Jupiter’s visible wavelength response to the impact of comet Shoemaker-Levy 9 using the Hubble Space Telescope. Her latest research involves the imaging of Neptune and Uranus with the Hubble Space Telescope, W. M. Keck Observatory,(which houses a pair of much larger (ten-meter) telescopes with an “adaptive optics capability” that eliminates the smearing effect of the Earth’s atmosphere), Mauna Kea Observatory, the NASA Infrared Telescope Facility (IRTF) at the peak of Hawaii’s highest mountain, Mauna Kea and other Earth based observatories.

Aurora Borealis – Best Light Show on Earth July 21, 2009

Posted by chemfan in Astronomy, Solar and Space weather.
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Sergey Zinovichik has his blog at:       http://chemfan.wordpress.com/

Red and Green Aurora

Aurora Borealis or commonly named The Northern Lights is a natural display of lights in the North Pole regions of our globe.  The lights appear as flowing streams of color in the sky taking different shapes and contours and often look like a multicolored curtain coming down from outer space.

The light show comes to us courtesy of our Sun.  Electrically charged particles produced on the Sun are ejected in all directions and a great amount of them head toward Earth.  As these particles (called solar wind) encounter the Earth’s outer regions, the magnetic field of the Earth begins to interact with the particles.

What results is a change in energy and direction of the particles: they head along magnetic field lines toward the poles of Earth.  Just like a bar magnet has its field lines returning at the opposite ends so the Earth’s magnetic lines come together around the poles.  This is why the aurora borealis is brightest and most easily seen in the northern regions of our planet.

Image taken from Wikipedia.org

Image taken from Wikipedia.org

The colors that we see in the aurora get produced from the collision of solar wind with atoms and molecules of our atmosphere.  Every atom and molecule has around them orbiting electrons.  The electrons sit in different energy levels with the highest energy electrons being furthest from the nucleus.

Although the orbits of electrons around the atom are complicated we can represent  their arrangement with a simple picture:

Electron orbits

We can see the first important aspect of orbiting electrons: They can only have certain energies analogous to planets orbiting at certain distances from the Sun.

When a fast moving solar wind particle collides with an atom the electrons in the atom “jump up” to a higher energy level.  The electrons in this excited state are usually unstable and will eventually fall back down releasing the energy they absorbed.  The way electrons release energy is in the form of electromagnetic radiation or what we would call light.

Image taken from HowStuffWorks.com

Image taken from HowStuffWorks.com

The type of light emitted depends on the type of atom that was excited.  This is because an oxygen atom’s energy levels differ somewhat from a nitrogen or helium atom.  The energy released corresponds to a certain visible color and the color corresponds to the energy that was lost as the electron returned to its previous state.  The colors we see in aurorae are regular because the energy levels in an atom are the same and because electrons can assume only certain quantized energies.

In some aurora red and green colors are prevalent.  This is characteristic of oxygen atoms being excited and releasing energy.   Molecular nitrogen can produce blue or violet colors.  Helium in rare occasions can produce orange light.  Compounds of oxygen and nitrogen can produce their own characteristic light.

When a mixture of different colors comes together the aurora we see is colored white just like the visible light from the sun put together from all the colors of the rainbow appears white.

Image Taken from APOD

Image Taken from APOD

The beauty of the Northern Lights can sometimes come down from the polar region and become visible at lower latitudes.  This is due to periods of high solar wind corresponding to unusual activity on the Sun.  In August and September of 1859 The Northern Lights were seen from the Midwestern region of the United State and were very bright.   Worldwide reports of unusual aurora intensity and frequency  that year were confirmed by magnetographs recording high levels of magnetic activity from the Kew observatory in England.

The southern pole of the planet experiences a similar phenomenon called Aurora Australis or Southern Polar lights and this light show is visible only in the southern hemisphere.

If you are fortunate enough to live in a part of the globe that has auroral displays you will probably agree that the light show that nature displays cannot be rivaled by anything humans can create.

Image taken from APOD

Image taken from APOD

New Impact on Jupiter July 21, 2009

Posted by jcconwell in Asteroid, Astronomy, planets.
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Jupiter-impact

Taken from the article by Nancy Atkinson at Universe Today

Amateur astronomer Anthony Wesley from Canberra, Australia captured an image of Jupiter on July 19 showing a possible new impact site. Anthony’s image shows a new dark spot in the South Polar Region of Jupiter, at approximately 216° longitude in System 2. It looks very similar to the impact marks made on Jupiter when comet Shoemaker-Levy 9 crashed into the gas giant in 1994. (But read the Bad Astronomer’s post that the black spot could also be weather.)
UPDATE (7/20): It has been confirmed this is an impact on Jupiter. Mike Salway shared the news Glenn Orton from JPL has imaged the Jupiter black spot with the NASA Infrared Telescope and he has confirmed it’s an impact.

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.”