CAIRO, June 7 (IslamOnline.net) - On Tuesday, June 8, around five billion people may be able to watch a celestial alignment that no human alive today has ever seen.

The phenomenon is "Venus Transit," where we "earthlings" will be able to see the planet cross the face of the Sun, a rare phenomenon that last occurred in 1882, according to Agence France-Presse (AFP).

The Venus Transit Animation  begins at the surface of Venus where heat ripples distort the scene in a shimmering heat bath. As we leave Venus and move off into space, we arrive at Earth and watch as Venus falls behind us and finally passes across the face of the Sun.

Unlike a solar eclipse, no-one will note any perceptible darkening: the Sun's light will dim by just a tenth of one percent, and Venus will appear as a small black disc inching its way, from about 0513 to 1126 GMT, across the star's surface.

People should view it indirectly by projecting the image through binoculars or a telescope onto paper, or by watching it on television or the Internet, AFP said.

Anyone looking at it directly must wear proper filters. To look at the Sun without protection can cause blindness.

"During a little more than six hours, planet Venus will cross the face of the Sun, offering a wonderful show for everybody to admire," the European Southern Observatory (http://www.vt-2004.org/) said.

"Nobody should miss the opportunity to witness this great event. And -- good luck! -- it appears that the observing condition prospects are rather favorable in large areas of the world."

Only six transits have ever been recorded: in 1631, 1639, 1761, 1769, 1874 and 1882. The next will be in 2012, but the one after it will be in 2117.

"It's an extremely rare event," said Gordon Bromage, a professor of Astrophysics at the University of Central Lancashire, a focal point for British observations about the transit (http://www.transit-of-venus.org.uk/vt-2004/).

The reason is because Venus, the second planet from the Sun, has an orbital plane that is slightly tilted to Earth, the third planet.