The Earth screen saver displays an image of the Earth as currently
illuminated by the Sun, from a variety of viewpoints. You can view
the Earth from the Sun (day side), the night side, from the Moon, or
from an arbitrary altitude above any point on the globe specified by
latitude and longitude. Day and night regions of the globe are shown
based on the current date and time. The image of the Earth shifts
location on the screen every 10 minutes to avoid burning in the
phosphor in one location.
The Earth Screen Saver is available exclusively for 32-bit Windows systems
such as Windows 95/98/Me and Windows NT/2000/XP.
The Earth Screen Saver is in the public domain. You can do
anything you like with it. The images are generated based on
the
cloudless Earth
databases created by the
NASA
Goddard Space
Flight Center from the
MODIS
instrument onboard the
Terra
satellite. The image of the Earth by night is based on nine
months of observation by the
Defense
Meteorological Satellite
Program. For further information and additional images, visit
the NASA Earth
Observatory site.
Downloading and Installation
After you've downloaded the program archive, extract the files
in it with
Info-ZIP or a
compatible archive extract program, and follow the instructions
in the included README.TXT file to install, configure, and
activate the screen saver on your system.
Source Code
Experienced C programmers who wish to modify the screen saver or
simply look under the hood to see how it works may download the source
code. You're welcome to use this source code in any way you like, but
absolutely no support is provided for it--you're entirely on your own.
Note that the bitmaps included in the source code archive are
reduced resolution and colour gamut images prepared expressly
for this screen saver. If you're looking for cloudless
Earth images for other applications, you're better off starting
with the higher resolution, 24 bit per pixel images available from
the aforementioned NASA site.
Release 2.0a Remains Available
The current 3.0 release of the Earth Screen Saver is a
large (more than 4 Mb) program which consumes substantial
CPU resources to render the image of the Earth. Users of
older machines with modest memory and CPU capacity by
present-day standards may prefer to install release 2.0a,
which uses a lower resolution topographical map of the
Earth from which it synthesises a subdued night side image,
avoiding the need for a separate night side database.
For further details, please visit the
Release 2.0a
page.
Related Software on this Site
Home Planet
The Earth Screen Saver was developed based on
Home Planet, a
comprehensive Earth and sky simulator for Windows which displays the
Earth, tracks satellites, asteroids, and comets, includes an
extensible multimedia object catalogue, a simulated telescope for
viewing the sky at any magnification or location, a database of more
than a quarter million stars, and a complete hypertext help file and
introduction to astronomy linked to the components of the program.
Displays include the illuminated portion of the Earth, the Sky, the
Telescope, the Earth as viewed from a satellite, the Moon, or the Sun,
an orrery, panels displaying current information about the Moon and
planets, and more. Real-time astronomical information can be exported
to other applications via DDE. There's even a
cuckoo clock
(you can turn it off).
Web Resources
- Earth and Moon Viewer.
- Your Sky: interactive planetarium.
- Solar System Live: interactive orrery.
- Terranova: a new terraformed planet every day.
For Windows:
- Home Planet,
- Moontool,
- an Excel catalogue of the Palomar
Observatory Sky Survey, and
- Craters screen saver,
- Sky screen saver,
- Terranova screen saver,
- Slide Show screen saver,
- Bullets screen saver,
- Millennium screen saver.