Andromeda Galaxy--M31   We live in the the Milky Way Galaxy, population 400 billion stars. Our closest neighboring system that looks anything like us is the Great Galaxy in the constellation of Andromeda, population 600 billion stars. Its distance from us is about 2.6 million light years. Andromeda and the Milky Way are key players in a small cluster of 34 galaxies called the Local Group. Like the Milky Way, Andromeda has two satellite galaxies. The large starlike object to the left of center, M32, is really a galaxy, as well as the wispy small spiral, M110 in the lower right. They both orbit Andromeda. Even though Andromeda has more stars, the Milky Way has more mass, making it the largest galaxy in the Local Group. Click on the image to make it larger.   SEFICK/Becker photo...

Andromeda Galaxy--M31   Add color to the Andromeda Galaxy and it's possible to see that the internal structure varies. The color of the stars near the bright center appears more yellowish, while out in the spiral arms the color is bluer. The stars in Andromeda's center, called Population II stars, are older--"deader" and redder, while the stars more distant from the center are called Population I stars. They appear bluer and are newer. The sun's location puts it squarely in the suburbs of our galaxy, at the point in the picture where the yellow is fading into the blue. Click on the image to make it larger.   SEFICK/Becker photo...

Whirlpool Galaxy--M51:   M51, located near the end of the handle of the Big Dipper, shows what seems to be a knot of material at the end of one of its spiral arms. In reality, it is a small spiral galaxy which is being torn apart by the gravitational influences of the more massive Whirlpool. The smaller galaxy, NGC 5195, is behind the Whirlpool, but is nonetheless interacting with it. One of the dust lanes of M51 appears to be drawn into it or is superimposed upon it as the two galaxies are passing each other. The mottled appearance in the arm of the Whirlpool closest to NGC 5195 has been caused by new star generation. As the two galaxies have been passing each other, turbulence has caused a burst of star-forming activity in these regions. Click on the image to make it larger.   SEFICK/Becker photo...

Great Globular Cluster in Hercules--M13:   Orbiting the center of our galaxy like miniature galaxies in themselves, globular clusters can contain up to a million stars. M13, about 22,000 light years distant from the sun, is the best example of such a stellar system that can be seen from the Northern Hemisphere. Globular clusters are older aggregates of stars, formed early in the history of galaxies. They are composed of stars like our sun or stars which have less mass than the sun. Gravity keeps the clusters intact. Stellar densities are as high as 100 stars per cubic light year at the centers of these systems. Click on the image to make it larger.   SEFICK/PRINCE/BECKER/Becker photo...

Eagle Nebula/Pillars of Creation--M16:   The Eagle Nebula was made famous by the Hubble Space Telescope (Click on image). The pillars themselves are dust clouds immersed in a glowing cloud of luminous hydrogen gas. They are stellar nurseries. Embedded within their tips are contracting clouds of hydrogen on their way to becoming stars. Radiation from nearby stars (top of photo) is shredding the tips of the pillars, pushing away much of the dust from where stars are forming. "The Pillars of Creation" is a more recent name given to the Eagle Nebula. It lies about 7000 light years from us in the constellation of Serpens, the Snake. Click on the image to make it larger.   SEFICK/Becker photo...

Lagoon Nebula--M8:   The Lagoon is also a stellar nursery. The lavender color results from glowing clouds of hydrogen gas. Invisible ultraviolet radiation from hot, new stars immersed within the Lagoon cause the electrons of the hydrogen atoms to become excited and move to higher energy levels. Sometimes they are ionized or stripped away from their attracting protons. When these electrons are eventually recaptured, the electrons cascade down many different energy levels. Some of these transitions give off light, thereby allowing us to see the hydrogen gas. The dark sinuous strand which characterizes the Lagoon is created by dust within the forming cluster of stars obscuring the light from the glowing hydrogen gas. Click on the image to make it larger.   SEFICK photo...

Dark Nebula:   What appears to be a lack of stars in a very rich portion of the Milky Way is very deceptive. The dark blotches are really large clouds of interstellar dust obscuring the multitude of stars behind them. This galactic pollution is representative of countless supernovae which have seeded the galaxy with heavier elements. In the beginning, the universe was mostly hydrogen and helium. Given enough time, hydrogen and helium can evolve into living things. We humankind are a piece of the universe which has become self-aware. Click on the image to make it larger.   SEFICK photo...

Horsehead Nebula:   Below and slightly to the right of the bottom star in the belt of Orion, the Hunter, lies the Horsehead--probably the most famous cloud of interstellar dust. The horse's body is observed from the rear with its head turned towards the observer. The overall number of stars in the lower half of the photo is less than in the upper half, indicating that an interstellar dust cloud is obscuring them. There is, on average, about one dust particle per 100 cubic yards of space. Click on the image to make it larger.   SEFICK photo...

Trifid Nebula--M20:   The Trifid shows three types of nebulosities in one photo: dark, emission, and reflection. The lavender glow comprising the largest portion of the nebulosity is distinctive of glowing hydrogen gas. This is the emission nebula. The three dark lobes which trisect the glowing hydrogen and give the nebulosity its name are dark obscuring clouds of dust. This is the dark nebula. The smaller blue portion of the Trifid is caused by dust dispersing the blue light of nearby young hot stars. This is the reflection nebula. You may have already guessed, the Trifid is another stellar nursery. Click on the image to make it larger.   SEFICK/Becker photo...

Crab Nebula--M1:   Chacoan priests routinely awoke to greet the sun. On the morning of July 5, 1054 AD, they saw in the east, in what today is called the constellation of Taurus, the Bull, a brilliant new star next to a thin waning crescent moon. The event has been immortalized in a rock art panel (click on image) where it can be seen today near Peņasco Blanco at Chaco Culture National Historical Park. At present, astronomers observe the remnants of an exploded star, called a supernova, and see at its heart a neutron star (pulsar) rapidly spinning at over 30 times per second. Click on the image to make it larger.   SEFICK/Becker photo...

Dumbbell Nebula--M27:   Stars have several ways of dying. One of the least common paths is when stars supernova, or blow themselves apart. The threshold mass for a traditional supernova event is about nine times that of the sun. Stars from several solar masses to the least massive stars in our universe will go through an instability stage near the very ends of their lives. As a red giant star, they will rapidly fluctuate in brightness and energy production, eventually shedding a considerable percentage of their matter into space. This is what has happened in the case of the Dumbbell. Click on the image to make it larger.   SEFICK/Becker photo...

Dumbbell Nebula--M27:   In the center of the Dumbbell is a faint but very hot star called a white dwarf. It is the inert helium or carbon-oxygen core of the once bright red giant that evolved by shedding its outer shells of gas (see above). The white dwarf, about the size of Earth, radiates at a temperature of 150,000 degrees F. Its energy is responsible for causing the ejected gases to glow. The color can identify the fluorescing gases: red for hydrogen, green for oxygen, and blue for nitrogen. M27 is 1250 light years away with the major axis of the hourglass about three light years in length. Click on the image to make it larger.   SEFICK/Becker photo...

Ring Nebula--M57:   Like a smoke ring blown into space, the Ring nebula represents the debris blown off of a red giant star as it died. The ring was thought to have been a bubble of gas ejected by the dying star. Since we were looking through the bubble, its circumference would have appeared denser. However, the Hubble Space Telescope has shown the Ring nebula to be indeed a ring. A hole is being punched out by jets of gas spraying out at right angles to the ring along the paths of least resistance. The white dwarf star seen in the center of the Ring is providing the ultraviolet energy which is causing the gases of the ring to fluoresce or glow. Click on the image to make it larger.   SEFICK/PRINCE/BECKER photo...

Jupiter:   Jupiter is our solar system's largest planet. Measuring 89,000 miles in diameter, it is large enough to accommodate all of the other material of the solar system with the exception of our sun. It is not destined to become a star. In order for Jupiter to initiate hydrogen burning like the sun, one would need to add the mass of about 70 more Jupiters to the planet. Ironically, Jupiter the star would be just a bit smaller than Jupiter the planet. Jupiter, however, is radiating two-and-a-half times more energy than it receives from the sun. It is still cooling from its formation (contraction) five billion years ago. The darker belts are areas of descending gases while the white zones are regions of ascending material. Click on the image to make it larger.   CARL photo...

Moon:   Our nearest neighbor in space, the Moon, can provide hours of enjoyable viewing through telescopes or just with the unaided eye. In this CCD image, it is possible to discern two basic types of landforms: the darker maria and the lighter highlands. The highlands represent the original lunar crust, which cooled and was cratered by leftover debris in the early history of the solar system. The darker maria (seas) resulted when huge meteorites struck the moon about 3.9 billion years ago, gouging basins up to 700 miles in diameter. The basins were eventually filled with lava, covering the first two billion years of lunar history.. Click on the image to make it larger.   CARL photo...