Observations

Visual Magnitude Estimates Exercise
Date: 4/28/10
Time: 9-10 PM
Location: Venice
Conditions: Clear, some clouds in West
Observations:
Eta Ursa Majoris: 1.9
Beta Leonis: 2.3
Gamma Leonis: 2.1
Zeta Leonis: 3.5
Lambda Leonis: couldn't see it
Epsilon Virginis: 2.7
Eta Virginis: couldn't see it
epsilon Corvi: 3.1
Epsilon Bootis: 2.6
Beta Bootis: 3.6

Date: May 1
Time: 8:10-8:50
Location: Venice
Conditions: Clear, still a little light near horizon
Observations:
Venus low in West near Aldebaran, both around 10 degrees high
Orion: low in West, can see Betelgeuse but not Rigel, which is blocked by trees
Canis Major: In SW, Sirius easily visible
Auriga: In WNW, Capella blocked by a small cloud, about 25 degrees high
Ursa Minor: Polaris and two other stars visible in N, Polaris is about 25 degrees high
Ursa Major: could see 5 of 7 main stars in Big Dipper
Castor and Pollux visible high in the West
Procyon: about 40 degrees high WSW
Mars: about 65 degrees high in the W, reddish tint, bright very close to Regulus
Saturn: about 60 degrees high in the SE

Date: May 15
Location: Venice
Conditions: partly cloudy
Time: 8:45-9:45
Mars: Bright and red in the west, about 55 degrees high
Regulus/Leo: about 60 degrees WSW, bright. can see general shape of Leo
Saturn: about 65 degrees high in the South, in Virgo
Arcturus: found by using arc of Ursa Major, about 55 degrees in the East
Spica: about 45 degrees in SSE, found by moving from Arcturus to Spica. Could see other stars around Spica but couldn't make out Virgo
Ursa Major: could see all 7 stars in big dipper, could see overall structure of bear
Hercules: could easily see keystone in ENE about 35 degrees high
Procyon:low in West, about 10 degrees high, hardly visible
Castor and Pollux: about 25 degrees high WNW, couldn't see all of Gemini because it was too low
Ursa Minor: could see 4 stars in little dipper

Date: May 22
Time: 9:05-10:05
Conditions: Clear
Location: Venice
Observations:
Moon: Waxing Gibbous, about 55 degrees SSW, could see a lot of lunar surface features
Saturn: SSW about 65 degrees, only about 10 degrees separating the moon and saturn. in Virgo, used binoculars and could see very faint line that appeared to be rings.
Spica: about 50 degrees high in the South
Mars: red and bright, about 40 degrees high in the West
Arcturus: almost directly overhead, by far the brightest star in surrounding area.
Regulus: about 5 degree separation with Mars, about 45 degrees high, a little south of west
Procyon: just visible over the horizon in the West, only star visible in Canis Minor
Castor and Pollux: WNW about 25 degrees high
Polaris: about 25 degrees in the North, could see 2 other stars in Ursa Minor
Vega: was very low when first started observing, by end of observation time it was about 25 degrees high in the NE
Deneb: In NE, could hardly see it because it was so low
Alberio: ENE, about 10 degrees high
Summer Triangle: could easily see Vega, barely see Deneb, could not see Altair
Northern Cross: could see Deneb, Alberio, and one other star. the others were either too low or too dim.

APOD 4.8 Station and Shuttle Transit the Sun

In this image, there are two small dark spots on the sun. However, they aren't sun spots. They are actually the International Space Station and the Space Shuttle Atlantis transiting the Sun. The bigger object is the ISS and the smaller one is Atlantis. The ISS and Space Shuttles are often seen streaking across the sky together during the night, but it is much rarer to see images of the two objects on the disk of the Sun. The two objects are orbiting about 350 kilometers above the Earth's surface. This image was taken about 50 minutes before the shuttle docked with the space station and this mission should be Atlantis' last mission.

Apod 4.7 Tentacles of the Tarantula Nebula

The Tarantula Nebula is located in the Large Magellanic Cloud and is the largest, most violent region of star formation in the Local Group of Galaxies. It is also known as 30 Doradus. It is an emission nebula, indicated by its red and pink coloring which is caused by the Hydrogen Alpha line radiation. Supernova remnants and dark nebula also exist there. The brightest region, which is just left of center is called R136 and contains many of the most massive, hottest, and brightest stars known. This star forming region would take up half of our sky if it were at the distance of the Orion Nebula. This is the most detailed image of this region ever taken.

Apod 4.6 Iguaçu Starry Night

This image was taken at the Iguacu Falls National Park on the border of Brazil and Argentina in the Southern Hemisphere. Many prominent objects are visible in the night sky and in this image, including Alpha Centauri, Beta Centauri, the Coalsack, the Southern Cross, both Magellanic Clouds, the Carina Nebula, Sirius, and Canopus. From our location, only Sirius and Canopus are visible in the constellations Canis Major and Carina, respectively. It is nice to see this image because we have also studied Alpha and Beta Centauri, and both Magellanic Clouds, but have so far not been able to see them in the sky because our latitude is too high in the Northern Hemisphere. Another intriguing feature is the influence of light on the picture coming from Argentina's Iguazú Falls International Airport. The center of the image is very bright from the light coming from the airport, so either the airport must be very close and/or very bright. I didn't realize an airport could cause that much light and affect a region of the sky that is so large.

Apod 4.5 The Antennae

This image parallels with our study of galaxy interactions. This image shows two galaxies colliding in the constellation Corvus, some 60 million light years away. Their collision has triggered rapid star formation near the center of the collision. One of the most interesting features of the image is the presence of two tails extending from opposite sides of the collision. They were created by matter being flung from the scene of the collision by gravitational tidal forces. These two streaks give the constellation its name, The Antennae.

Interacting Galaxies

http://hyakutake1957.files.wordpress.com/2008/04/colliding-galaxies.png
http://cosmology.net/images/Collidinggalaxies5678.jpg
http://news.nationalgeographic.com/news/2006/10/images/061019-galaxies_big.jpg
http://www.spacedaily.com/images/supernova-discovered-pair-colliding-galaxies-antennae-bg.jpg
http://farm4.static.flickr.com/3614/3490531897_6426a8d0e7.jpg
http://www.foxnews.com/images/366647/0_21_galaxies_hubble_6.jpg
http://talklikeaphysicist.com/wp-content/uploads/2008/04/collidinggalaxy-1.jpg
http://physics.uwyo.edu/~stark/outreach/galaxy/colliding/
http://www.twinlitworlds.com/hubble/pix/jpgsfull/collision.jpg
http://mainland.cctt.org/biolab/images/Colliding_Galaxies_HST_Gif.gif
http://www.noao.edu/gateway/intergal2.gif
http://farm4.static.flickr.com/3628/3462762896_e4fdd54774.jpg
http://www.spacedaily.com/images/arp-87-pair-interacting-galaxies-bg.jpg
http://www.noao.edu/image_gallery/images/d5/vv150b.jpg
http://www.etsu.edu/physics/wars/arp107.jpg
http://coolcosmos.ipac.caltech.edu/cosmic_kids/learn_sirtf/images/interacting.gif
http://astro.uchicago.edu/~grodnick/gallery/galaxies/m51-irg_hogg.jpg
http://housefly.astro.princeton.edu/~rhl/PrettyPictures/M51-4x4.jpg

Apod 4.4 The Bloop: A Mysterious Sound from the Deep Ocean

This picture is a visual representation of the Bloop, which was a sound recorded in the Pacific Ocean in 1997 using deep sea microphones that had been spy microphones in World War 2. In the graph, time is shown on the horizontal axis, deep pitch is shown on the vertical axis, and brightness designates loudness. It is the loudest sound ever recorded in an ocean at over 150 decibels and was audible 5,000 kilometers away and by two different microphones that were over 3000 miles apart from one another. The sound is similar to that of a blue whale, but the blue whale isn't large enough to create such a monstrous sound. Two potential explanations are that there could be a gigantic life form at the bottom of the ocean that we have yet to discover, such as a prehistoric animal that survived through the extinction periods, or that an iceberg calving, an undersea earthquake, or an undersea volcano caused the noise. Since the bloop was recorded, no other bloops have been heard.

Astronomy Cast Ep. 177: Mysteries of the Milky Way, Part 2

How many spiral arms does the Milky Way have?:
There are man different types of spiral galaxies, from normal and barred, to even smaller classifications in each broader group. The arms are caused by density waves moving through the Galaxy. When you look at the galaxy in different wavelengths, you get different data on how many arms there are. Therefore, blue light was selected as a constant of observation. In blue light, the Milky Way appears to have 2 spiral arms.
Sibling Stars: Did other stars form in our solar nebula? What happened to them?
Everything starts out bound together in a star forming region. Over time, the star-forming region stretches out and the sibling stars start to separate. The best way to match with siblings is to match the Sun's composition with other stars'. Unfortunately, non-sibling stars can match as well.
Mass-extinctions:
Seem to trend every 60 million years. Are we due?
When the solar system goes through the Galaxy's disk, it goes through areas of high and low density, we become susceptible to cosmic rays and higher asteroid rates in the high density areas.
G-dwarfs: dwarf stars in the G part of the H-R diagram. They should be more abundant than large stars, but aren't. Why?
There should be a group of stars formed right after the Big Bang that are almost purely hydrogen and helium, but we haven't found a single one yet. They are called Population 3 stars. One explanation is that without the presence of metals, only giant stars could form out of pure hydrogen and helium. The other solution is that the first stars were so giant that they lived and died before any small stars could form. This prevents any G dwarves from forming, and therefore nothing that formed before the first generation of supernovae is capable of still being alive today because the supernova polluted space with metals.
Where are the intermediate mass black holes? We've found stellar mass and supermassive black holes, but only a couple of intermediate size black holes in the whole galaxy. We don't have enough evidence currently to have any real plausible conclusions.

Astronomy Cast Ep. 176: Mysteries of the Milky Way, Part 1

There are many mysteries in our galaxy that have puzzled astronomers for many years.
Blue stragglers are stars in globular clusters that are not old and neither off of the main sequence nor are red dwarfs. These stars are high mass blue stars on the main sequence that are well above the main-sequence turn off. These stars shouldn't last more than a few millions years, but they are part of clusters that are billions of years old. One theory is that these stars formed later, but this idea does not fit our models of the universe. The other idea is that two stars collided and formed one big, bright, blue star. The two star could also be members of a binary that merged or have had mass-transfers.
Supernovae are supposed to occur every century, however our Milky Way Galaxy has not produced a supernovae since 1680. Dust clouds could have possibly blocked our sight of some of these supernovae.
Another question is whether the Magellanic Clouds are satellite galaxies or not. Due to the presence and uncertainty of dark matter, calculations are not certain about whether the galaxies are related to our own or not. Depending on calculations, the two galaxies could either be unattached and zipping past us, or could be gravitationally bound together around the Milky Way.
Proxima Centauri is believed to be part of the Alpha Centauri system, but it could also be just very close to Alpha Centauri A+B. Alpha Centauri's stars have the same composition, but Proxima Centauri has a different composition. Also, Proxima Centauri is at the farthest point in its projected orbit, so it is uncertain whether Proxima Centauri is connected to Alpha Centauri or not.
Eta Carina is a massive object in the constellation Carina. Eta Carina had a "false nova event" in 1843. Other stars that have gone through this turned into supernovas. Therefore, we could see a supernova from Eta Carina very soon.

David Levy Biography

Kenny Smith
Mr. Percival
Pd. 00
30 Apr. 2010
David Levy
David Levy is a Canadian astronomer who was born in 1948. He married Wendee Wallach-Levy on March 23rd, 1997. He has attended a multitude of universities, including McGill University, Acadia University, Queen’s University, University of Arizona, the University of Tampa, and Hebrew University, where he just in the last few months finished studying and earned a doctorate. Levy has discovered 22 comets, including Comet Shoemaker-Levy 9, which impacted Jupiter. Levy is also a prolific author and has made a big impact on recent astronomy.
David Levy’s biggest impact on astronomy has come through the study of comets. He ranks third in history in the amount of comets discovered by one person. Altogether, he has discovered twenty-two comets, including nine in his own backyard. The other comets he discovered as part of a team composed of himself, his wife, and Eugene and Carolyn Shoemaker. He even aided in the discovery of two other comets, although he is not given credit as one of the discoverers. Levy is the first person to ever discover comets using three different methods: visual, photographic, and electronic observations.
Although Levy is most famous for his numerous discoveries of comets, he has also found many asteroids. His first asteroid discovery was that of asteroid 5261 Eureka. This asteroid was not only the first asteroid Levy discovered, but was also the first Martian Trojan asteroid ever discovered. The Trojan asteroids share Mars’ orbit, so Levy can indirectly be credited with leading to the discovery of all of the Martian Trojan asteroids that we know of today. Together, with Tom Glinos and his wife Wendee, David Levy has discovered over 60 asteroids.
Levy’s most famous discovery was that of the comet Shoemaker-Levy 9. Shoemaker-Levy 9 was a periodic comet, meaning that its orbital period was 200 years or less. The comet was discovered in 1993 at the Palomar Observatory in California. The comet was the first comet to ever be discovered orbiting a planet instead of the Sun. It is believed that about twenty to thirty years prior to its discovery it had approached too close to Jupiter and had been captured by the gas giant. When the comet was discovered, it had an odd shape that could only be explained by a close encounter with Jupiter in which Jupiter’s tidal forces pulled the comet apart. As astronomers continued to study the comet, it was concluded that the comet would collide with Jupiter in July of 1994. This would be the first collision ever visually observed between two objects in our solar system or in space. Astronomers were ecstatic over the possibility of being able to see deeper into the atmosphere of Jupiter. The collisions occurred on the side of Jupiter invisible to Earth, but the collision sites were visible moments after the impact due to Jupiter’s fast rotation rate. Overall, 21 distinct impacts were observed over a six day period and the collisions formed dark, round spots that were as easy to see as the Great Red Spot and that stayed visible for months after the impacts. The discovery and subsequent impact of the comet shot Levy into instant stardom. He became a household name for several years and was bombarded with requests to do interviews for all of the major television networks.
Levy currently hosts his own radio talk show on astronomy, has written 35 books on a multitude of subjects, mostly on astronomy, is the President of the National Sharing of the Sky Foundation, and is part of the Jarnac Comet Survey in Vail, Arizona. He has received numerous awards for his many astronomical achievements, but he will be forever known for his greatest accomplishment, the discovery of Shoemaker-Levy 9.

Works Cited
"About David." Welcome. 2004. Web. 30 Apr. 2010. .
Arnett, Bill. "SL9." The Nine Planets Solar System Tour. 24 July 1997. Web. 30 Apr. 2010. .
“David H. Levy.” Encyclopædia Britannica. 2010. Encyclopædia Britannica Onlne. 29 Apr. 2010 < http://www.britannica.com/EBchecked/topic/338050/David-H-Levy>.

APOD 4.3 Ash and Lightning Above an Icelandic Volcano

The recent volcanic explosions in Iceland have created so much as that they have cancelled flights across Europe. The ash and dust has drifted across Europe and engulfed the whole continent. The ash is still thick that many planes are still left grounded. But what created so much ash? The Eyjafjallajökull volcano in southern Iceland began erupting on March 20, with a second eruption starting under the center of a small glacier on April 14. Neither eruption was particularly powerful, but the second explosion melted a glacier that fragmented lava after it cooled and the lava pieces were carried up with the rising volcanic plume.

APOD 4.2 Spitzer's Orion

The Orion Nebula, M42, is a star forming region some 4o light years across. It is 1500 light years away and is visible in the constellation Orion. The young stars in the nebula experience fluctuations in brightness and the Spitzer Space Telescope is keeping tabs on the young stars. One of the causes for the aforementioned changes in brightness is the presence of dusty, planet forming disks, which can pass between our point of view and the star's light, thus affecting the amount of light that reaches us. The brightest stars in the nebula are part of the Trapezium cluster and all of the stars in the nebula are only about 1 million years old, compared to our sun's age of 4.6 billion years. The image was taken in false color that was caused by the absence of Spitzer's liquid coolant, which ran out in 2009.

Observations

Date: 4/6/10
Time: 8:30-8:40
Location: Venice, FL
Conditions: Dark, Clear
Observations:
Venus: 10 Degrees high in the West
Brightest whole object in the whole sky.
Flickering a little.
Consistent white color
Mercury: 8 degrees high in between the West and WNW
Very faint, to the right of Venus and down a few degrees
Flickering a lot
Color changing between red and white\
**About 3 degrees of separation between the two objects.

Date: 4/7/10
Time: 8:15-8:25
Location: Venice, FL
Conditions: just passed sunset, still fairly bright near the horizon, only about 10 objects visible in total.
Observations:
Venus: 12 degrees high in the West
Very Bright
Mercury:
about 10 degrees high in the West between W and WNW
Sun still not set, so its even fainter than when observed at darker hours. Just barely visible, occasionally escaping from view for a split second because it was so dim.
*** Again about 3 degrees separation between the two objects.

APOD 4.1 Venus and Mercury in the West

All around the world, Venus and Mercury are very close together in the western sky. These two planets have just passed conjunction and are starting to slowly grow apart. The two planets will remain almost as close together as they were at conjunction for a few days, before quickly separating as Mercury plummets to the horizon. This conjunction is ideal for observations of Mercury. Mercury is often hard to identify because it is very faint. Often, the Sun's glare prevents us from seeing the closest planet to the Sun. Even when not obstructed by the Sun, Mercury is faint and hard to identify if you do not look at the sky often enough. However, with Venus' close approach, it is very easy to tell which object Mercury is. Venus is by far the brightest object in the night sky and is very easy to identify low in the west. At our latitude, the best viewing is about 30 minutes after sunset. At this point in time, both Venus and Mercury are fairly bright and easily visible.

APOD 3.8 Detailed View of a Solar Eclipse Corona

During a solar eclipse, the solar corona, the sun's outer atmosphere, is visible. This faint, thin outer layer is not bright enough to be seen on a normal day, only during a solar eclipse. Its not that the corona is not bright, its just that the photosphere, the part of the sun that we see (the surface), is so much brighter than the corona that it overwhelms it and the corona is not visible. The intricate structure of the corona is easy to see with the naked eye, but when it is photographed, the structure is incredibly hard to capture. During the 2008 solar eclipse in Mongolia, this image was taken. This picture is a composite of many images and digital processing. You can easily see layers and the glowing caustics of an ever changing mixture of hot gas and magnetic fields. You can see the shape of the magnetic fields above small pink solar prominences.

Apod 3.7 Yukon Aurora with Star Trails

This image captures, in my opinion, two of the coolest features in the night sky: star trails and auroras. Star trails are created when a camera is attached to a tripod and the camera is left with an open exposure. The camera is centered on the north star, Polaris. As the Earth rotates, the stars slowly traverse the sky surrounding Polaris and when viewed in the camera, you can see the path of the star from the start of the image to the end of it. Auroras occur when reactions between charged particles from the sun and the magnetosphere send particles to the pole, where they interact with the atmosphere, creating colored streaks across the sky. Auroras occur mostly at high latitudes. In areas of high latitude, auroras often occur around the equinoxes. Both the spring and fall equinoxes offer excellent times to see auroras in these high latitude regions. In order to capture both the star trails and the aurora, many short exposure images were combined together to create the star trails so that the aurora could be captured as well.

Astronomy Night

Date: 3/6/2010
Time: 6:40-9:25
Location: Pine View School
Sky Conditions: exceptionally clear, very dark
Observations:
Helped to operate three different telescopes:
1. Operated a telescope directed towards M42. I explained that M42 is located in Orion in Orion's sword and is called the Orion Nebula. I explained how the three bright stars visible are called the Trapezium and provide the energy needed to excite the atoms in the gas cloud surrounding the stars, and that this excitation allows you to see the nebulosity.
2. I helped run the telescope pointed at Saturn. You could easily see the planet and its beautiful rings, and I informed people that you could also see two of Saturn's moons.
3. I also ran the telescope pointed at the binary pair of Rigel. I explained how the brighter star and the less luminous white dwarf are locked in orbit around each other but that the white dwarf is much smaller, so the light it gives off is much harder to see in comparison to that given off by Rigel. I also told people where the white dwarf was located (lower right of Rigel) in case they could not find it.
Also helped setup a few telescopes

Apod 3.6 Exceptional Rocket Waves Destroy Sun Dog

The Solar Dynamics Observatory, or SDO, designed to perpetually observe the sun, launched a few weeks ago. The blurry image of the rocket which carried SDO can be seen near the center of this image, surrounded by unexplained shock waves. There has been much debate over the origin of these ripples and the leading hypothesis is that they were caused by a sonic boom that occurred when the shuttle broke the sound barrier. Also to the right of the image is a sun dog. Sun dogs are extra images of the Sun caused by falling ice-crystals in the Earth's atmosphere. After the ripples had passed, the sun dog disappeared. When the waves hit the ice crystals, they were rearranged, thus destroying the sun dog. It is still under question why other rockets do not produce as noticeable shock waves.

Quarter 3 Biography Percival Lowell

Kenny Smith
Mr. Percival
Pd. 00
2/26/10
Percival Lowell
Percival Lowell was born on March 13th, 1855 in Boston, Massachusetts. He came from a family that produced many famous minds and personalities. He graduated from Harvard University in 1876. Before he decided to pursue a career in astronomy in 1893, he had served in many different fields, including foreign relations and affairs. In 1877, Italian astronomer Giovanni Schiaparelli had studied an opposition of Mars and he had found what looked like canals engraved into the Martian surface. These observations intrigued Percival Lowell and led him to start a career in astronomy.
Percival Lowell wanted to have the best viewing conditions possible for his observation of Mars at opposition. He wanted to see if Schiaparelli’s canals really did exist. Lowell conducted research and, with a hint from fellow astronomer W. H. Pickering, decided that Arizona would be the best place for his research. The site that he picked was just west of Flagstaff and was situated at an altitude of seven thousand plus feet. Lowell established the Lowell Observatory in this spot. From 1896-1897 he moved the observatory to a site in Mexico, but he soon realized that Arizona had a better viewing ability. Lowell was able to make what he believed to be clear observations of Mars, but his findings were eventually proven wrong. Percival Lowell’s decision to set up an observatory in an area of excellent seeing ability produced great results and inspired other astronomers to do the same. Nowadays, these types of observatories that are far from the light and smog of cities are by far the majority.
Lowell’s observations of Mars led him to formulate a hypothesis about intelligent life on the planet Mars. Percival Lowell believed that a civilization was trying to survive on a dying Mars. He believed that this alternative life form had built canals that went to the polar caps. Lowell presumed that these caps melted annually. Once the caps started to melt, the canals would fill with water and irrigate the crops that were keeping the civilization alive. Lowell observed dark spots on the Martian surface, which he credited to fertilized crops that he called “oases”. Lowell observed an ongoing darkening from poles to the equator as the seasons advanced from winter. This corresponded with his idea about vegetation and the release of water from the polar caps. Lowell started making drawings of the images he saw in his telescopes and released three books containing his findings. His work was highly criticized by his fellow astronomers but the public latched on to his ideas. Lowell’s ideas were largely discredited and were finally proved wrong when Mariner 4 took the first pictures of the Martian surface in 1965.
After his obsession with Mars, Lowell moved on to other planets. While studying Uranus, he discovered a discrepancy in Uranus’ orbit that is not fully accounted for by the pull of Neptune’s orbit. Therefore, Lowell deduced that a “Planet X” must exist beyond the orbit of Neptune. Lowell continually searched and photographed regions of the sky where he expected the new planet to be located. He died in 1916 before he could find the elusive planet. Then, in 1930, Clyde Tombaugh discovered the mysterious Planet X. This planet was named Pluto and its planetary symbol, a P with the base of an L, is meant to represent not only the first two letters of Pluto, but also Percival Lowell’s initials. Pluto was much fainter and smaller than expected because the discrepancy did not actually exist. The discrepancy was caused by a miscalculation of Neptune’s mass and affected the numbers Lowell used in his calculations.
Lowell also spent time making observations of the other planets in the Solar System, but compared to the time he spent looking for Pluto and observing Mars, these planets did not receive as much attention. Lowell was a daring astronomer who made bold predictions that could have shocked the world. Unfortunately for Lowell, most of his predictions were eventually discredited. If his predictions had come true and if he himself had discovered Pluto, Lowell would most likely be the most famous astronomer to have ever lived. His main legacy is in the realm of observing, for he was the first real pioneer of having good seeing to be able to make accurate observations.
Works Cited:
"Lowell, Percival." Complete Dictionary of Scientific Biography. Vol. 8. Detroit: Charles Scribner's Sons, 2008. 520-523. Gale Virtual Reference Library. Web. 25 Feb. 2010.
"Lowell, Percival (1855-1916)." The Worlds of David Darling. Web. 25 Feb. 2010. .
"Percival Lowell." Encyclopædia Britannica. 2010. Encyclopædia Britannica Online. 25 Feb. 2010 .
"Percival Lowell." Lowell Observatory. Web. 25 Feb. 2010. .

APOD 3.5 Cassini Spacecraft Crosses Saturn's Ring Plane

The Cassini Spacecraft that orbits Saturn has recently taken an image of Saturn's rings edge on. The rings seem to disappear in the image because their width is so small. The rings have a diameter of over 250,000 kilometers, but they are only one kilometer thick. The disappearance of the rings occurs on Earth every 15 years as the rings and our Earth are edge-on. This particular image was taken in February 2005 when the Cassini orbiter was in direct line with the rings. The image uses false colors so you can easily see the rings. In the rings, you can see small bumps that are actually small moons orbiting in the plane of the rings and some of them actually orbit inside of the rings. The shadow of the rings can be seen reflected on the "surface" of Saturn. These shadows can not be seen today due to Saturn's position in its orbit.