• Venus

No living person has ever seen this unusual phenomenon which last took place over one hundred and twenty years ago in 1882.

The University astronomers are setting up telescopes and live web links at two sites in the city centre, offering local people an opportunity to experience the transit first hand rather than watching it on television. 

They will also be giving out special scientific solar viewers so that the transit can be viewed safely without damage to eyes.

Venus will be seen as a black dot passing across the surface of the sun between approximately 7.00am and 12.30pm, visible to the naked eye as a black dot even without the use of a telescope.

At the Bargate there will be several telescopes set up for viewing and solar viewers will be available from 8.30am until 1.00pm. 

In WestQuay from 9.00am visitors will be able to watch the event on a large screen via a live Internet link to a professional telescope situated in another part of the world. 

During the afternoon the screen, which will be on the lower shopping level, will remain in situ to repeat pictures of the event. 

At both venues, the University's expert astronomers will be on hand to explain exactly what is happening and why it is important.

Transits of Venus occur when the planet lies on a straight line between the Earth and the Sun. 

On average, there are just four Venus transits in about 243 years. 

The first astronomers to use telescopes to observe the transit of Venus were Englishmen Jeremiah Horrocks and William Crabtree in 1639.

Malcolm Coe, Senior Lecturer in Astronomy at the University, explains: 'In 1882 planetary transits were very important to astronomers because, at a time when there was little knowledge of the size of the solar system, they enabled accurate measurements of the distance of the Sun from Earth. 

Of course, our knowledge of the solar system has increased substantially since then, but the transit is still a spectacular sight and a once-in-a-lifetime event. 

What we hope to do is to help people find out more about what's happening and experience it first hand.'

Experts will also be visiting Cantell School at 9.00 am to set up a live web link to a telescope and talk to about 100 pupils between the ages of 11 and 16.

The planet Venus is the second closest planet to the Sun and our nearest planetary neighbour. 

Named after the Roman goddess of love and beauty, it is one of the most beautiful objects in the sky.  Viewed from Earth, it can outshine every celestial body except the Sun and the Moon. 

At its brightest, it may be seen in the daytime sky.  Astronomers refer to Venus as Earth's sister planet because both are similar in size, mass, density and volume. 

Both formed at the same time and condensed out of the same nebula.