Jupiter from Voyager

Picture Credit: NASA, JPL, NSSDC, Voyager

Explanation: Imagine a hurricane that lasted for 300 years! This picture of the planet Jupiter was taken by the Voyager 1 spacecraft as it passed the planet in 1979. Jupiter, a gas giant planet with no solid surface, is the largest planet in the solar system and is made mostly of the hydrogen and helium. Clearly visible in the photo is the Great Red Spot, a giant, hurricane-like storm system that rotates with the clouds of Jupiter. It is so large three complete Earths could fit inside it. Astronomers have observed this giant storm on Jupiter for over 300 years.

Original material on this page is copyrighted to Robert J. Nemiroff and Jerry T. Bonnell.

The Night Side of Saturn

Picture Credit: NASA, Jet Propulsion Laboratory,Voyager Project

Explanation: This image of Saturn was made in November 1980 by the Voyager 1 spacecraft as it flew past the ringed gas giant planet. From a spectacular vantage point, looking back toward the inner solar system, the robot spacecraft recorded this view of the night side of Saturn casting a sharp shadow across the bright rings. No Earth based telescope could ever take a similar picture. Since Earth is closer to the sun than Saturn, only the day side of the planet is visible from the Earth.

Original material on this page is copyrighted to Robert J. Nemiroff and Jerry T. Bonnell.

NGC 4214: Star Forming Galaxy

Credit: John MacKenty (STScI) et al. & the Hubble Heritage Team (AURA/ STScI/ NASA)

Explanation: Dazzling displays of star formation abound across the face of galaxy NGC 4214, a mere 13 million light-years away in the northern constellation Canes Venatici. While this 1997 Hubble Space Telescope image shows the numerous faint, older stars of NGC 4214, the most eye-catching features are the galaxy’s bright young star clusters surrounded by fluorescent gas clouds. Sculpted into bubbles and filamentary shapes by energetic explosions and stellar winds from massive cluster stars, the clouds fluoresce in the intense stellar ultraviolet radiation. The colorful spectacle of massive young star forming clusters and distinguished presence of a fainter, older stellar population indicate that NGC 4214 has experienced star formation episodes spanning billions of years.

The Cartwheel Galaxy

Picture Credit: NASA, Hubble Space Telescope

Explanation: The Cartwheel Galaxy shows a ring that is the result of a collision between a small and a large galaxy. After a small galaxy has moved through a big galaxy – in this case one that probably resembled our own Milky Way – a star formation wave moves out from the impact point like ripples across the surface of a pond. When galaxies collide it is rare that any two stars actually collide. Gravity, however, causes density waves to move out through the galaxy which in turn triggers the formation of hot, bright young stars, producing the ring that we see in this picture.

Original material on this page is copyrighted to Robert J. Nemiroff and Jerry T. Bonnell.

The Hooker Telescope on Mt. Wilson

Picture Credit: Mount Wilson Observatory

Explanation: In the 1920s, pictures from the Hooker Telescope on Mt. Wilson fundamentally changed our understanding of the cosmos. Astronomer Edwin Hubble, using photographs he took with this telescope, demonstrated that the objects his contemporaries called “spiral nebulae” were actually huge systems of stars – spiral galaxies, similar to our own Milky Way galaxy but incredibly distant. Prior to Hubble’s work it was argued that the spiral nebulae were mere clouds of gas and that they, along with everything else in the universe, were contained in our own galaxy. The Hooker Telescope mirror is 100 inches in diameter which is nearly the size of the mirror of the orbiting Hubble Space Telescope named in Hubble’s honor. The Mount Wilson Observatory offers a “virtual walking tour” of this historic telescope.

Original material on this page is copyrighted to Robert J. Nemiroff and Jerry T. Bonnell.

The Cat’s Eye Nebula

Picture Credit: NASA, Hubble Space Telescope

Explanation: Three thousand light years away, a dying star throws off shells of glowing gas. This Hubble Space Telescope image reveals “The Cat’s Eye Nebula” to be one of the most complex “planetary nebulae” known. In fact, the features seen in this image are so complex that astronomers suspect the visible central star may actually be a double star system. The term planetary nebula, used to describe this general class of objects, is misleading. Although these objects may appear round and planet-like in small telescopes, high resolution images reveal them to be stars surrounded by cocoons of gas blown off in the late stages of evolution.

Original material on this page is copyrighted to Robert J. Nemiroff and Jerry T. Bonnell.