... Note: Click here a longer, much more comprehensive overview of the polar aurora . ... Magnetic Field . ... Aurora . ... 3b. Fritz Aurora . ... Electrons . ... Typical aurora (Dick Hutchinson ї) . In Alaska, Canada, Norway, Finland or northern Russia, on a clear night, a greenish glow is often seen in the sky, known as the "Northern Lights." ... Auroral light is produced at a height of about 100 km (60 miles) when fast electrons, arriving from space, slam into atoms and molecules of the atmosphere. ...

... a greenish glow is often seen in the sky, known as the "Northern Lights." ... During magnetic storms, the glow may move southwards, and on occasion it can be seen in much of the US. ... A similar phenomenon is also seen in southern polar regions. ... Auroral light is produced at a height of about 100 km (60 miles) when fast electrons, arriving from space, slam into atoms and molecules of the atmosphere. ... The green light of the aurora puzzled scientists for many years, since it fit no known...

... SUN MOON MERCURY VENUS MARS, JUPITER SATURN . ... Mars . ... Previously understood that magnetic fields were directly related to rotation, so when I read that Mars, like Venus, didn't have one, my understanding crumbled. What exactly causes magnetic fields in planets? ... RELATED TOPICS: MAGNETIC FIELD . Planetary magnetic fields are definitely related to rotation, but directly not so much. ... Get instant access to subscriber content on Astronomy.com! ...

... Apache HTTP Server Version 2.2 . Apache > HTTP Server > Documentation > Version 2.2 > Modules . ... To enable mod_dav , add the following to a container in your httpd.conf file: . ... In addition, a location for the DAV lock database must be specified in the global section of your httpd.conf file using the DavLockDB directive: . ... In order for mod_dav to manage files, it must be able to write to the directories and files under its control using the User and Group under which Apache is running. ...

Modules | ... Apache HTTP Server Version 2.4 . Apache > HTTP Server > Documentation > Version 2.4 > Modules . ... Basic HTTP authentication . ... This module allows the use of HTTP Basic Authentication to restrict access by looking up users in the given providers. ... This module should usually be combined with at least one authentication module such as mod_authn_file and one authorization module such as mod_authz_user . ... Module: . ... Location /demo> AuthBasicFake demo demopass </Location> . ...