Credits
Earth 21st Century is powered by WordPress. Theme used is Victoria.
Images in the header:
- Vistula Planet
- Wee Planet Frisco from The Roof of Bolt | Peters
- Seine planet
- Zurriola espigon planet
- Austin Mini Planet
- Planet 1
- X-Planet 3
- Planet #3
Plugins used:
- Akismet
- AutoMeta
- Contact Form 7
- DoFollow
- Easy Gravatars
- Full Text Feed
- Google Sitemaps Generator
- MCEComments
- No Self Pings
- SEO Slugs
- Simple Tags
- Smart YouTube
- Sociable
- Subscribe to Comments
- Top Posts by Category
- Wordpress Database Backup
- WYSIWYG Plugin For Wordpress
Feeds are 
Feedburner.