1 NASA

www.nasa.gov/

The undisputed world champion of all space sites offers a mind-blowing range of stuff, from photos, celestial maps and in-depth information to the chance to watch shuttle launches and interviews with astronauts on their own NASA television channel

2 Hubble

hubblesite.org/

Videos and stunning high-resolution pictures from the galaxy's most famous telescope

3 Google Sky

earth.google.com/sky/skyedu.html

Download the much-hyped sister app to Google Earth to zoom in to distant galaxies and view constellations and the movements of the planets

4 Spacejunk

www.space.com/spacewatch/space_junk_list.html

An alarming 8,000-odd pieces of discarded satellite and general rubbish are orbiting the earth at any time - and that's just the ones that are being monitored. Find out who the space litterbugs are with this country-by-country ranking

5 More space junk

orbitaldebris.jsc.nasa.gov/

OK, so it's another mention for NASA, but this spin-off site shows the seriousness of the space junk problem, with compelling images that show all the rubbish spinning around the globe like a cross between Saturn's rings and a salvage yard

6 Debunking space myths

www.badastronomy.com/bad/misc/

Were the Apollo landings faked? Can you really stand an egg on one end during the vernal equinox? These and other space misconceptions are comprehensively debunked here

7 Profiting from space

www.spacemart.com/

Be amazed at the proliferation of commercial opportunities in the skies above you - and find out how to grab a slice of the action

8 Satellite tracker

www.heavens-above.com/

Is that moving object in the night sky a plane or the international space station? Detailed star charts and times of visibility mean you can track satellites from your back garden

9 Black holes

cosmology.berkeley.edu/Education/BHfaq.html

For anyone who's ever wanted to understand the physics behind these strange objects, Ted Bunn of Berkeley University has put together an easy-to-understand FAQ

10 UFO sightings

http://www.ufowatch.com/

If you've ever seen a UFO or believe you've been abducted by aliens, this is the place to visit. Apparently.

11 Mars map

WWW.GOOGLE.COM/MARS

Essentially, Mars is a rocky, barren lump of brownfield site. That hasn’t stopped it from being endlessly fascinating. Here, Google and Nasa collaborate to provide a map of the planet with enhanced colour, zoom and all that jazz. A highlight is the immense Valles Marineris rift, which will compete with the Grand Canyon come the day of space tourism.

12 Mapping the cosmos

WWW.WIKISKY.ORG

The sky may seem like a great big bag of nothingness. In fact, it’s full of stuff, which the Wikisky site makes apparent. Viewers can soar into the heavenly firmament, surrounded by the half a billion astronomical objects so far recorded by the Sloan Digital Sky Survey, a project that has been mapping the cosmos from a New Mexico observatory since 1998.

13 Envisat satellite

WWW.EARTH.ESA.INT

Launched in 2002, the European Space Agency’s Envisat satellite circles the globe making continuous observations of the land, sea and atmosphere. The Esa site makes it plain that it’s doing us good: the section called Benefits for Europe shows how “space technology can be turned into business opportunities in non-space sectors”. Very worthy.

14 Virtual Martian habitat

WWW.EXPLOREMARSNOW.ORG

In 2004, George W Bush reiterated his father’s dream to make a manned mission to Mars a reality. The creators of this website think it’ll happen by 2015. Eager to be the first off the mark, they’ve built a virtual Martian habitat, based on input from engineers and designers. A feature allows an imaginary Mars base with living room, bedroom and a bit called “personal hygiene”.

15 Solar System Simulator

SPACE.JPL.NASA.GOV

Stars, comets, black holes… This collaboration between the Nasa-sponsored Jet Propulsion Laboratory and the California Institute of Technology has created the Solar System Simulator, in which hours can be spent gazing at planets from a multitude of different viewpoints. Now you can see what the sun looks like from Mars without having to go blind.

16 Easy science

WWW.SPACE.COM

This is the popular science end of space. You don’t need to know about magnetic loop fields to enjoy it. It’s easier, cheaper and possibly more punctual than Sir Richard Branson’s Virgin Galactic. And somehow it reminds you that, like a riot or a football match in winter, it’s probably better to watch space on a screen at home rather than to be up there in a tin can, eating bad food and inhaling recycled air.

17 UK space research programme

WWW.SUNEARTHPLAN.NET

Don’t forget us, pleads this British website. The UK’s space research programme gives us yet more space, and would like to emphasise the UK’s pivotal role in space science. We Brits may be earthbound lummoxes, but we host a “vibrant solar-terrestrial physics community” whom we should salute. This site is an action-packed, science-oriented romp, co-ordinated by Dr Jim Wild of Lancaster University.

18 Planet hopping

WWW.SOLARVIEWS.COM

Once upon Earth, we had “island hopping”. Soon we shall have planet hopping, and this site should be the brochure. The content is written like an idiot-proof guidebook (“Saturn is the sixth planet from the sun,” runs a typical opener), with crowd-pleasing pictures and quizzes. On one game, you can find out how old you would be had you been born on another planet: anyone aged 57 would be just 30 on Mars.

19 Night Sky Observer

WWW.NIGHTSKYOBSERVER.COM

The Night Sky Observer (NSO) is an astronomy and space news website. Most pages (especially news and podcasts) are updated several times a day.

20 Moon phase calendar

WWW.MOONPHASEINFO.COM

Check out what phase the moon is in with this interesting site.