Taurus:

The constellation of Taurus (The Bull) lies along the ecliptic - apparent path of the Sun, the Moon and the Planets in in their year-long journey across the sky. Consequently, Taurus is one the constellations of the Zodiac. North of Taurus lie the constellations of Auriga and Perseus and to the south lies the constellation that represents the Hunter of The Bull, Orion.

The Myth:

According to myth, princess of Phoenicia, Europa, was a stunningly beautiful young woman. Upon seeing her for the first time, Zeus, the King of the Gods, fell madly in love with her. Feeling that he must have her as his mistress, he disguised himself as a massive, milky white bull and placed himself in amongst the other cattle in Europa's father's herd.

Europa and her hand maidens were visiting the seashore while the disguised Zeus grazed amongst the other cattle. When Europa noticed the massive bull, she became enchanted with its majesty, gentleness and grace. She gathered some wild flowers, wove them into a wreath and walked over to the bull. Placing them on the bull's head, she climbed upon his back. The bull slowly and gracefully carried the maiden around the pasture and then walked to the seashore. Europa was not fearful at all during her ride. Suddenly, to Europa's horror, the bull charged into the ocean and swam all the way to Crete with the helpless Europa still on his back.

Unable to escape the Island of Crete, Europa eventually bore Zeus a son, Minos, who later became the father of the creature Minotaur, who was half bull and half man.

Zeus celebrated his love of Europa by naming the continent of Europe after her and by placing the constellation of Taurus in the sky for everyone to forever witness Zeus' power and fertility.

TAURUS HIGHLIGHT

The Crab Nebula - A Supernova Remnant:

As mentioned in the pop-up info window in the main constellation image above, what we today view as "The Crab Nebula" is actually the expanding remnant of a supernova explosion that was first witnessed on Earth in the summer of the year 1054.

The image of the Crab Nebula below, taken with the FORS2 (FOcal Reducer and Spectrograph) instrument attached to the European Southern Observatory's Very Large Telescope "Kueyen", is actually a composite of three images taken through three different optical filters. Each filtered image has been assigned a different color; the green and red represent Hydrogen and Ionized Sulfur gas (respectively) that was ejected during the star's explosion and now forms a cloud ten light years in diameter that is expanding at the incredible velocity of over 1,100 miles per second. The light blue color in the central region highlights free electrons that have been accelerated to extremely high energies (velocities near the speed of light) by the intense magnetic fields generated by the remnant neutron star at the nebula's center. (More about the neutron star below.)

Image credit: Credit: FORS Team, 8.2-meter VLT, ESO

The Crab Pulsar - A Rapidly Spinning Neutron Star:

As a massive star ages, it goes through periods where it expels large amounts of its stellar atmosphere into space. Eventually, after perhaps several of these outbursts have occurred, the nuclear furnace at the star's core finally runs out of fuel. At this point, the delicate balance between the outward push of the star's radiation and the inward pull of its gravity is disrupted. In less than a second, the remaining mass of the star (as much as 25 - 50 times the mass of the Sun) collapses due to the now overwhelming force of gravity. The remaining stellar material is crushed to extreme densities and heated to billions of degrees.

At these incredible densities and temperatures the electrons, protons and neutrons that originally made up the stellar gas are crushed together and packed so tightly that the electrons (negatively charged) and protons (positively charged) are forced to combine and form additional neutrons. The newborn neutron star, who's original diameter was several times that of our Sun, has been reduce to a ball of densely packed neutrons somewhere between 6 and 10 miles across!

If you could transport just a teaspoonful of neutron star material to Earth, it would weigh an incredible one billion (1,000,000,000) tons!

As the parent star collapses and transforms into its neutron star state, its rotation rate increases dramatically as well. We've all seen a slowly spinning ice skater with her arms and free leg extended. As she slowly tucks them in closer and closer to her body, she begins to spin faster and faster. The same process occurs with our star. Originally, it may have had a rotation rate of anywhere from one rotation in a few hours to once in several weeks. Now, as a tiny neutron star, it can be spinning at the incredible rate of dozens of times per second! (Some neutron stars, through a process that may occur later in its development, actually get "spun up" from their initial rate and have been found to be spinning at over a thousand times per second! These exotic creatures are called "millisecond pulsars".)

Within hours of its creation, the incredible gravity of collapsed star has sucked massive amounts of the star's original inner atmosphere onto its surface. At these extreme temperatures and densities, the nuclear reactions that are occurring within this collected material are increasingly violent. Eventually, a catastrophic thermo-nuclear explosion of incredible energy rips from the surface of the collapsed star. The explosion blasts all of the accumulated material out into space at speeds in excess of 30 million miles per hour (8,500 miles per second or nearly five percent of the speed of light), leaving the naked, now rapidly spinning neutron star behind.

The Crab Pulsar is the 950-year-old remnant of one such explosion.

A "Pulsar" Is A Neutron Star, But A Neutron Star Isn't Necessarily A "Pulsar":

Everything about a neutron star is exotic, including its magnetic field, which can be trillions of times as strong as our Earth's. The neutron star's magnetic axis probably will not line up with its rotational axis as shown in the diagram below. (This type of misalignment is not uncommon; our Earth's own magnetic axis is misaligned with its rotational axis by several degrees.)

Image credit: NASA's Marshall Space Flight Center and Science@NASA

In the violent environment near the neutron star, extremely energetic electrons and positrons (the anti-matter equivalent of electrons) are constantly swarming around, guided by the star's magnetic field lines. Because the star's magnetic field lines are so incredible strong, some of the energetic particles are funneled into a jet that streams out along the magnetic axis from each pole at nearly the speed of light.

The beam of energized electrons and positrons sweeps around as the star rotates, just like the beam from a lighthouse beacon. If we here on Earth happen to lie in the path that the jet sweeps out, we see a flash of light, radio waves, x-rays and even gamma rays each time the beam passes by us.

Click on the image below to start a Java animation illustrating the rotation of a pulsar and its beam sweeping past a viewer on the Earth.

Of course, if we view the Crab Pulsar through an optical telescope, we won't actually see it flash, due to its extremely rapid rotation. Our eyes simply aren't equipped to discern flashes of light at 30 times a second!

Electronic instruments, however, which are sensitive to radio waves, infrared radiation, ultraviolet radiation and x-rays and gamma rays, are able to capture the faint, but rapid, flashes as well as the radiation emanating from the expanding nebula.

The images below (from left to right) represent the Crab Nebula as seen in x-rays (by the Chandra X-Ray Telescope), in visible light (from the Palomar Observatory), in infrared light (from the W. M. Keck Observatory) and in radio wavelengths (from the Very Large Array). The three right hand images are all to scale relative to each other. The Chandra X-Ray image on the left, however is a close-up of the central portion of the nebula. It clearly shows the disk of million-degree gas spiraling around the pulsar and the jets spewing out relativistic particles from each magnetic pole.

NASA/CXC/SAO	Palomar Observatory	W. M. Keck Observatory	VLA/NRAO

Crab X-ray & optical Crab X-ray & infrared Crab X-ray, radio & optical Crab X-ray, infrared & optical Crab X-ray, infrared, radio & optical

At right is a window in which you can view composite images of those shown above. Simply choose the combination that you want to see and it will appear in the window.

The Hubble Space Telescope And Chandra X-Ray Telescope Team Up To Peer Into The Heart Of The Crab Pulsar:

To most people, the night sky is virtually unchanging. With the exception of the Moon (which obviously changes from night to night), a few of our planets (which change positions over periods of months or years), and the Constellations (that change with the seasons), everything else pretty much just seems to remain the same, year after year.

To the keen eyes of our orbiting telescopes, however, the Universe is a dynamic and ever changing arena. Between August, 2000 and April, 2001, the Hubble Space Telescope peered into the heart of the Crab Nebula and took 24 separate images. The Chandra X-Ray Telescope captured 8 images of the same area from November, 2000 through April, 2001. A dramatic composite of the visible light image from Hubble and the x-ray image from Chandra is shown below.

X-Ray X-Ray Image Credit: NASA/CXC/ASU/J. Hester, et al. Optical Image Credit: NASA/HST/ASU/J. Hester, et al.

The HST portion of the image is the reddish background that also shows individual stars. The Chandra portion is the bluish and white region that shows the multi-million degree gas swirling in a torus (doughnut) around the neutron star as well as the jet of energetic particles spewing out in opposite directions from it.

The high resolution images produced by the two instruments revealed the changes that had occurred over the 8-month period of observation. Combining the sequence of images, the astronomers were able to produce fascinating time-lapse movies of the changing environment around the neutron star.

HST/Chandra Movie: MPEG Format (4.68 MB)	HST/Chandra Movie: QuickTime Format (6.56 MB)	HST Movie: MPEG Format (4.71 MB)	HST Movie: QuickTime Format (6.05 MB)

X-Ray X-Ray Image Credit: NASA/CXC/ASU/J. Hester, et al. Optical Image Credit: NASA/HST/ASU/J. Hester, et al.

Two versions of the movie are available. The first depicts the wide angle Chandra X-Ray view side by side with the visible light Hubble view. Note the dynamic ripples of energy pulsing outward from the area near the neutron star as well as the stream of energetic particles being shot out at right angles to them.

The second movie is the HST view alone, in which the ripples of energy and the jet of matter and antimatter are quite evident.

Each animation is available in either MPEG or QuickTime formats. Most browsers will handle the MPEG format without any software plug-in. If you don't have the QuickTime Player, it can be downloaded and installed here.

To view the movies, click on the image for the video format you prefer. Please note that these files are large and can take several minutes to download if you have a dial-up (modem) connection to the Internet.