New Frontiers: Modern Perspectives on Our Solar System

New Frontiers: Modern Perspectives on Our Solar System
(24 lectures, 30 minutes/lecture)
Course No. 1823

Taught by Frank Summers
Space Telescope Science Institute
Ph.D., University of California at Berkeley

In recent years, cutting-edge telescopes, satellite imaging, and unmanned spacecraft have led to a fascinating series of discoveries that have changed our picture of the Sun and the family of objects that orbit it—including Earth. This new perspective has grown out of many intriguing findings such as these:

• The reclassification of Pluto as a dwarf planet, one of countless icy bodies—and not even the largest—in the outer solar system
• The 2005 landing of the Huygens probe on Saturn's moon Titan, which revealed a bizarre world where liquid methane acts like water does on Earth: falling as rain, carving channels in the landscape, and collecting in lakes
• One of the largest radiation and particle storms from the Sun ever recorded, which blasted interplanetary space in 2003 and offered a vivid demonstration of the ferocity of space weather
• The detection since the 1990s of several hundred planets orbiting other stars, allowing us to compare for the first time our solar system with other planetary systems

New Frontiers: Modern Perspectives on Our Solar System is a visually stunning and richly detailed investigation of what we know about the solar system today. Illustrated with insightful diagrams, amazing computer animations, and scores of spectacular images from telescopes and spacecraft, these 24 lectures show you a new and exciting way to view our celestial neighborhood—all under the guidance of astrophysicist and top astronomy educator, Dr. Frank Summers from the Space Telescope Science Institute (STScI).

Welcome to the 21st-Century Solar System

Often cited as the most profound change in our view of the solar system, the Copernican revolution of the 16th century proposed the philosophical shift that Earth and the planets orbit the sun instead of the universe revolving around Earth, as appeared to be the case from our vantage point.

But Dr. Summers, whose work at the STScI's Office of Public Outreach presents the findings of the Hubble Space Telescope and developments in general astronomy to the public through various media and educational outlets, suggests another candidate for the biggest change in our views.

"I think the space age is the most important epoch," he says. "It brought us new ways to observe the solar system in more wavelengths with bigger telescopes, new ways to analyze with better data and faster processing, and also a new way to explore, both with robots and with our own eyes."

Remodeling the Solar System

Not only does New Frontiers allow you to see the solar system with fresh eyes, it also offers you a new model to serve as an organizing guide. Gone is the familiar diagram you find in many old reference books depicting the Sun and nine planets forming a neat, straight line. Dr. Summers provides key points as to why this perspective is so outdated:

• A straight-line alignment of the planets occurs only every three quadrillion years—600,000 times the present age of our solar system!
• The distances between planets and their relative sizes compared to the Sun are wildly out of scale.
• Most importantly, there is so much more to the solar system than just these 10 objects.

You discover what Dr. Summers, an expert astrophysicist who headed the development of exhibits for the opening of the American Museum of Natural History's Rose Center for Earth and Space, calls the "21st-century solar system." He suggests that, instead of a straight line, the solar system is best seen as a bulls-eye with six concentric circles, each of which represents the six families of objects in our solar system. Working outward from the center, you have the following alignment:

• The Sun: The only star in our solar system.
• The rocky planets: Mercury, Venus, Earth, and Mars. Composed of rock, they are close to the Sun and have few or no moons.
• The asteroid belt: A band of small, mostly rocky bodies between Mars and Jupiter.
• The giant planets: Jupiter, Saturn, Uranus, and Neptune. Orbiting far from the Sun, these large planets have gaseous atmospheres, rings, and moons.
• The Kuiper belt: The region beyond Neptune now known to be the reservoir of the short-period comets containing mostly icy bodies (including Pluto).
• The Oort cloud: The reservoir of the Sun's long-period comets, located almost a quarter of the way to the nearest star.

The Usefulness of the Modern View

This modern view of the solar system is useful in many ways. Foremost, it provides you with a bigger picture of the solar system, organizing and classifying its objects based on similar characteristics and offering a better understanding of how they are grouped and structured.

In addition, it underscores the enormity of the solar system. Not only is the recently discovered Kuiper belt object Eris larger than Pluto, its orbit takes it almost twice as far from the Sun. The Oort cloud extends 500 times farther than Eris.

Another advantage to this new model is that it tells you the story of the formation and evolution of the solar system:

• Rocky planets formed near the Sun, where it was too hot for ices and gases to condense.
• Asteroids populate a zone where planet formation was disrupted by Jupiter's gravitational field.
• Jupiter and the other giant planets accreted in the region beyond the "frost line," where gas, ice, and rock were all available.
• The icy objects in the Kuiper belt and Oort cloud coalesced in the super-cold, low-density conditions beyond Neptune.

With a better grasp on this new picture of the solar system, you explore the space-age solar system as we now know it. This approach is comparative, reflecting the way that planetary science is conducted today: where the same phenomena are examined in all their variety from world to world. You consider these and other examples:

• Craters: These are found throughout the solar system. On the moon, craters can be dated to reveal a period of bombardment following the formation of the solar system. On Earth, one recently identified crater is thought to be the smoking gun in the demise of the dinosaurs.
• Weather: Weather on other planets can be markedly more severe than weather on Earth. Jupiter has a gigantic, centuries-old storm that could swallow several Earths, and the air temperature on Venus is more than 460° C.
• Moons: Moons are rich worlds unto themselves. Among the seven large and 160 small moons, our moon is unusual in that it is one-quarter of the size of its planet. Computer simulations show that it probably formed when a Mars-sized body smashed into the forming Earth.

Get Breathtaking Views

New Frontiers is illustrated with the many exhilarating views of the solar system afforded to us by continued advances in space technology. Indeed, there is no better guide for this visually rich journey than Dr. Summers, whose own work with scientific imagery (in the Academy Award–nominated IMAX film Cosmic Voyage and the IMAX short film Hubble: Galaxies Across Space and Time) reflects a deep understanding of and passion for the role that visualizations play in comprehending our universe.

From the celebrated rovers on Mars and the Galileo probe orbiting Jupiter or Cassini at Saturn to the lesser-known missions studying asteroids and comets, the pictures taken from ground-based observatories, space telescopes, and satellite missions help give you a clearer idea of just how critical the technological advancements of the space age have affected our views of the solar system. They also reflect the profoundly sublime nature of its diverse characteristics.

Fittingly enough, the course ends with a stunning movie from the Messenger spacecraft as it left Earth on its mission to Mercury—a movie that captures our slowly rotating planet growing ever smaller and that demonstrates a truly breathtaking new perspective on our solar system.

It is a perspective that continues to evolve as astronomers peer further into our galaxy and continue to explore the hundreds of planetary systems discovered around other stars. The stunning point of view on display in New Frontiers shows you just how much more there is to uncover about your true place among the stars.

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