|
|
|
Technical Notice:
Britannica is adding new external IP addresses to improve delivery of our online services.
For most subscribers, this will not impact access to Britannica Online and requires no action. However, if your network firewall is configured to block access to non-authorized IP addresses, please notify your network administrator of the following changes:
Britannica will add these external address ranges:
63.86.141.210-63.86.141.219
63.86.141.230-63.86.141.239
Britannica will be dropping the following range:
66.117.177.210-66.117.177.219
|
These changes will take place on Friday August, 24th. If you or your network administrator have any questions about these changes, please contact Britannica Technical Support at edsupport@eb.com or (800) 621-3900 x7160.
|
|
insideBritannica
get inside: A Retrospective on Pluto
|
|
 | | Pictured: Pluto and its large moon Charon. (NASA, ESA, H. Weaver (JHU/APL), A. Stern (SwRI), and the HST Pluto Companion Search Team) |
|
The American astronomer Clyde Tombaugh discovered icy Pluto in 1930 during a deliberate search for a ninth planet. By the turn of the 21st century, however, new revelations about this remote object and kindred bodies in the outer solar system were raising doubts about Pluto’s planetary status. A year ago, in August 2006, astronomers at their major triennial meeting in Prague stirred controversy by approving a definition of planet that excluded Pluto while creating a category called dwarf planet, for which Pluto and two other bodies qualified.
Pluto and its Moons
Because of Pluto's remoteness and small size, the best telescopes on Earth and in Earth orbit have been able to resolve little detail on its surface. Indeed, such basic information as its radius and mass have been difficult to determine; most of what is known about Pluto has been learned since the late 1970s as an outcome of the discovery of Charon:
What is a Planet?
The idea of what exactly constitutes a planet of the solar system has been debated for centuries. In August 2006, the general assembly of the IAU approved a definition for a solar system planet that excluded Pluto, instead defining it under a new distinct class of objects called dwarf planets:
Pluto as a Member of the Solar System
Although it is no longer considered a planet, Pluto is still a member of the Milky Way Galaxy that also includes of the following:
|
|
 | | Pictured: One of the discovery photographs of Pluto's moon Charon. (Official U.S. Navy Photograph)
|
|
Before Pluto’s large moon, Charon, was discovered in 1977, astronomers thought the two bodies to be one, and thus Pluto to be significantly larger and more massive than it actually is. Even in the discovery photos, Charon appears only as a bump on the side of Pluto. The nearness of the two objects, their great distance from Earth, and the distorting effects of Earth’s atmosphere made it extremely difficult to distinguish Charon from Pluto, even in the best telescopes of the time.
|
|
|
|
|
|
|
A brief overview of comets, highlighting their origin and their distinction from meteors, or shooting stars.
(Copyright © 2004 AIMS Multimedia)
View Video |
|
|
Learn about the major planetary, solar, and intergalactic phenomena, including galaxies, quasars, pulsars, novas, black holes, and the Big Bang.
(Copyright © 2005 New Dimension Media)
View Video
|
|
|
Asteroids: Is Planetary Armageddon Looming?
by Gregory McNamee
About 4.6 billion years ago, an asteroid bigger than Ceres, perhaps as large as Mars, collided with Earth and sent a vast cloud of sandy fragments and great chunks of rock into the atmosphere. These fragments eventually coalesced into the Moon. Could the heavens have another mega-collision in store for Earth? Could be... (read more)
The Britannica Blog is a place to share smart, lively conversations on just about any topic.
| |
|
Explore Different Countries with Britannica World Data
What is the average household size in Japan? What is the major export of Norway? Use Britannica’s World Data tool to answer these questions and enrich and expand your understanding of the world.
World Data Analyst allows you to create tables, charts, and even export the information to a spreadsheet for data crunching and deeper analysis. It includes easy access to statistics such as demographic, economic, health, literacy, transportation, communication, and military figures.
Easily accessible on the Britannica Online home page under “Research Tools”, World Data is ideal for in depth research, or just to learn more about the world.
Try it now!
| |
|
Encyclopædia Britannica World Atlas
Explore the countries and regions of the world with this complete, all-in-one resource. The new Encyclopædia Britannica World Atlas contains comprehensive content that ranges from stunning satellite images of every continent to detailed plans of the world's greatest cities.
Over 220 pages of mapping provide balanced coverage of all regions of the world, authoritative information, and colorful maps that enrich the learning experience at home, in the office, and in the classroom.
Order Encyclopædia Britannica World Atlas today for only $89, and get free S&H! Please mention promotion code AUGUST when ordering.
Call Britannica at 1-800-621-3900 or go online to www.eb.com to place your order now.
|
|
|
Free Web Training for Britannica Online Subscribers!
Britannica Online subscribers are invited to participate in online Encyclopædia Britannica training sessions! This is provided to see what's new with Britannica Online and learn different ways to use it in your school or library!
Academic Librarians will enjoy these 1-hour online presentations that they can attend without having to leave the library. Pick a date, complete the online registration form at www.eb.com/webcast, and invite your colleagues to join in this live presentation.
Note that there is a registration deadline 1 week before the session.
Space is limited, so please sign up soon!
| |
|
|
|
This message has been sent to %%email%%. This newsletter is a feature of Britannica Online Academic Edition.
Unsubscribe me from this mailing.
To withdraw by postal mail, send your request to:
Encyclopædia Britannica
331 N. La Salle St.
Chicago, IL 60610 USA
ATTN: Customer Service - Newsletter
Please allow up to 10 days for processing.
© 2007 Encyclopædia Britannica, Inc.
Privacy Policy | Help |
|
|
