 The Astronomy across time.- Dimensions and distances in Astronomy.
- Galaxies and clusters. The Milky Way and the Local Group.
- The Stars and the constellations.
- The Solar System: the Sun, the planets, the dwarf planets and the SSSBs.
- The movements of the Earth and their effects.
- The Moon and its phases.
- The eclipses.
- The Ecosphere.
Miscellaneous Astronomy Visual Dictionary.Definitions, images and pronunciation for almost everything in celestial bodies, astronomical observations and astronautics.
 Eath and Space.Excellent anvanced presentation on the Universe, the stars, the Sun, the planets of the Solar system, the Moon, eclipses, seasons, black holes, comets, asteroids, meteorites and space exploration.
 Cosmos4kids.com.The Universe, the galaxies, the stars, the Solar System, and more.
Journey through the galaxy.A very comprehensive and well organized overview of the Solar System, the stars, the galaxies… Basic course of Astronomy.The University of Hong Kong provides a short introduction to all major topics in Astronomy: History, planets, stars, black holes, eclipses and more. Brief history of Astronomy.This a chapter from the previous website, that explains how our ancestors interpreted the Universe across time. Top 10 moments in Astronomy.From Galileo's first use of the telescope to the discovery of the Big Bang. Living in space.20 things you probably didn't know about living in space. How long would it take to walk a light-year?To read carefully if you are used to plan weird backpacker summer trips. Exploring the Universe PlanetQuest.An historic timeline of Mankind's awareness and discovery of other planets. A most excellent resource by NASA.
5 unforgettable moments in the History of spaceflight and space exploration.Encyclopaedia Britannica's pick of the greatest hits in space exploration. We choose the Moon.2009 was the 40th anniversary of the first lunar landing. This superb website was set up to commemorate that historic event. The mission is recreated in precise detail right from pre-launch with actual voiceovers. You can change the views and also click on hotspots to view related media galleries. The site is divided into 11 sections where you can watch photos, videos, and other archival content.  Apollo 11.Google Earth Tour that describes the landing, moon walks, and the return to space of Apollo 11 with excellent visual aids and great narrations.
The Apollo missions on the Wikipedia.Don't forget to check the links to the Apollo 11 and Apollo 13 missions. The top 10 failed NASA missions.A look back at the top 10 American space missions that didn't make it. Satellites.Learn how satellites stay in orbit around the Earth. Interactive lesson at Skoool.co.uk. Uses of satellites.Learn some uses of artificial satellites. Interactive lesson at Skoool.co.uk. Ten amazing telescopes.A look at 10 of the most amazing telescopes of our time, including several that are still on the drawing board and promise to reveal images of the Big Bang itself.  NASA images.A wonderful collection of images taken by many of the NASA spacecrafts since 1958. You can browse them either by category or by spacecraft.
The International Space Station turns 10.A great collection of 32 high quality photos of the IIS, compiled for its tenth birthday. Stars, Galaxies, Nebulas and ConstellationsThe Planets Revolving planets.Amazing animation showing the movements of the planets from different perspectives.
Saturn.Sensational images of Saturn showing the ringed planet in incredible detail. The Big Picture: Saturn at equinox.During the equinox, the sunlight casts long shadows across Saturn's rings, highlighting previously known phenomena and revealing a few never-before seen images. The Big Picture: Martian skies.A wonderful selection of some of the best martian images ever made. Landscapes of Mars.Stunning satellite images of the Red Planet reveal avalanches, sand dunes and more. Explore Mars now.Landing on Mars is an inevitability. This website simulates a tour through the Martian landscape and a human colonized habitat. The walkthrough is a lesson in the science, technology, and design challenges that will be required to land man on the Red Planet. The EarthExamine evidence of Earth turning about an axis.Visualize an animation that demonstrates that the Earth rotates around itself at Exploring Earth online book. Explore a model of Earth's daily rotation.Visualize an animation that shows how the Earth rotates around itself at Exploring Earth online book. Day and night.Understand how the movement of the Earth causes day and night and the apparent daily movement of the Sun. Interactive lesson at Skoool.co.uk. Investigation: What time is it?A great series of activities to learn why and where it is daytime or night-time in any given moment.  Earth view.Want to know how the Earth looks like right now?
Explore a model of Earth's yearly revolution around the Sun.Visualize an animation showing how the Earth revolves around the Sun at Exploring Earth online book. The Seasons and day length.Understand how the tilt and movement of the Earth causes the seasons. Interactive lesson at Skoool.co.uk. The Seasons in Geography4kids.Learn how the relative position of the Earth to the Sun conditions the climate and the daylength. NASA's view of Earth.Selected collection of photos on the Earth taken by NASA's space missions. Examine Earth from a new perspective.Observe the Earth's maps of temperatures, volcanoes, earthquakes, water vapor and more, at Exploring Earth online book. Observe a visual model of Earth's spheres.Visualize the Earth system as a set of four overlapping and interacting spheres, at Exploring Earth online book. Investigation: How are Earth's spheres interacting?A great series of activities to study how the four spheres of the Earth interact, at Exploring Earth online book. Ten things you don't know about the Earth.Fantastic article that unravels some of the most significant facts about our planet... or did you already know that the Everest is not the biggest mountain? Our amazing planet: top to bottom.A huge panoramic view of our planet, from the highest peaks to the mysterious depths. What makes Earth special compared to other planets.A number of very special features are necessary for Life to exist on Earth. Learn about them in an article from LiveScience.com. Gravity satellite yields 'Potato Earth' view.The geoid is the Earth depicted according to the gravty of its surface. ESA's GOCE satellite shows it with an unprecedented accuracy. June 19, 240 B.C.: the Earth is round, and it's this big.Those were the great news more than 2,200 years ago. They took a time to spread around the globe, though. Stars, Galaxies, Nebulas and Constellations
The Star of Bethlehem
At this time of year it seems almost traditional for stargazers to ponder the age-old question of the origin of the Star of Bethlehem. The Star's appearance some 2,000 years ago is quite possibly one of the best-known celestial events in all of recorded history.
The topic has universal fascination, and is why Christmas Star shows still play to packed planetarium houses.
Perhaps the simplest answer that can be offered is that the Star might have been a nova: a new star suddenly blazing forth where no star had previously been seen. While for the most part such objects are really dying stars having a final fling of glory before descending the long road to ultimate extinction, there are some stars that go through such contortions more than once.
One such star is long overdue to pop and could do so at anytime.
Stargazing
The star in question is T Pyxidis, in the constellation of Pyxis, the Mariner's Compass. T Pyxidis is about 6,000 light years away and belongs to a small and seemingly exclusive group of cataclysmic variable stars called recurrent novae (NR). Astronomers have been patiently waiting for T Pyxidis's next outburst for more than 20 years.
Normally this star shines at magnitude 14: that's about a thousand times dimmer than the faintest star that can be perceived by most human eyes on a dark, clear night. But on five occasions, in 1890, 1902, 1920, 1944 and 1967, this star brightened dramatically to magnitudes between 6.5 and 7 (a 1,000-fold increase in brightness in the most extreme case) making T Pyxidis just bright enough to be glimpsed without any optical aid. These eruptions came at an average of just over 19 years apart, and the longest stretch of time between them was 24 years.
But this month marks 40 years since the last outburst.
It was back on Dec. 7, 1966 that the most recent eruption was first noticed by New Zealand amateur astronomer, Albert Jones. The star had more than doubled in brightness to magnitude 12.9. Just two nights later it was almost four magnitudes brighter and after a month it was glowing at magnitude 6.3 before slowly fading back to normal.
Nobody knows exactly why T Pyxidis has remained quiet for so long, but the general consensus is that it may have accumulated an extra-thick coating of nuclear fuel on its surface over these past 20 years, which would make it appear extra bright when it finally blows its next surge of gaseous debris out into space.
Who knows? That night could be tonight!
Key vocabulary
Analyse the text
- · What are astronomers expecting to happen and to what?
- · What is a nova?
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