Blue Marble 2000

Credit: R. Stockli, A. Nelson, F. Hasler,
NASA/ GSFC/ NOAA/ USGS

Explanation: This newly released digital portrait of our planet is reminiscent of the Apollo-era pictures of the “big blue marble” Earth from space. To create it, researchers at Goddard Space Flight Center’s Laboratory for Atmospheres combined data from a Geostationary Operational Environmental Satellite (GOES), the Sea-viewing Wide Field-of-view Sensor (SeaWiFS), and the Polar Orbiting Environmental Satellites (POES) with aUSGS elevation model of Earth’s topography. Stunningly detailed, the planet’s western hemisphere is cast so that heavy vegetation is green and sparse vegetation is yellow, while the heights of mountains and depths of valleys have been exaggerated by 50 times to make vertical relief visible. Hurricane Linda is the dramatic storm off North America’s west coast. And what about the Moon? The lunar image was reconstructed from GOES data and artistically rescaled for this visualization.

Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)

Sun Storm: A Coronal Mass Ejection

Credit: SOHO Consortium, ESA, NASA

Explanation: Late last month another erupting filament lifted off the active solar surface and blasted this enormous bubble of magnetic plasma into space. Direct light from the sun is blocked in this picture of the event with the sun’s relative position and size indicated by a white half circle at bottom center. The field of view extends 2 million kilometers or more from the solar surface. While hints of these explosive events, called coronal mass ejections or CMEs, were discovered by spacecraft in the early 70s this dramatic image is part of a detailed record of this CME’s development from the presently operating SOlar and Heliospheric Observatory (SOHO) spacecraft. Near the minimum of the solar activity cycle CMEs occur about once a week, but as we approach solar maximum rates of two or more per day are anticipated. Though this CME was clearly not headed for Earth, strong CMEs are seen to profoundly influence space weather, and those directed toward our planet and can have serious effects.

Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)

Southwest Mercury

Credit: Mariner 10, NASA

Explanation: The planet Mercury resembles a moon. Mercury’s old surface is heavily cratered like many moons. Mercury is larger than most moons but smaller than Jupiter’s moon Ganymede and Saturn’s moon Titan. Mercury is much denser and more massive than any moon, though, because it is made mostly of iron. In fact, the Earth is the only planet more dense. A visitor to Mercury’s surface would see some strange sights. Because Mercury rotates exactly three times every two orbits around the Sun, and because Mercury’s orbit is so elliptical, a visitor to Mercury might see the Sun rise, stop in the sky, go back toward the rising horizon, stop again, and then set quickly over the other horizon. From Earth, Mercury’s proximity to the Sun cause it to be visible only for a short time just after sunset or just before sunrise.

Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)

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.