When Mercury crossed the Sun
Posted on
On Wednesday, 7 May, the planet Mercury passed in front of the Sun, giving
astronomers - amateurs and professionals - a great opportunity to observe a
splendid phenomenon called ""transit"". This phenomenon is very similar to solar
eclipses, and Mercury appeared as a tiny black dot slowly crossing the Sun""s
disc.
The transits of Mercury occur at intervals between 3 and
13 years, the coming one will be on 8 November 2006. The transit lasted about 5
hours and 20 minutes, and it was globally visible from Asia, Europe and
Africa.
Egypt was one of the most favorable places to observe the entire
stages of the transit.
Observations from
Alexandria
Astronomer Aymen Ibrahim, the Planetarium
Astronomy Specialist at the Bibliotheca Alexandrina, observed the transit from
the Planetarium using a Sun-spotter, a special optical instrument that projects
a magnified image of the Sun onto a screen. Mercury and some other spectacular
solar features (sunspots and white-light faculae) were clearly observed in all
of the phases of the transit.
Mr. Ibrahim invited the interested
public to enjoy watching the heavenly wonder through the
Sun-spotter.
Space observations
The
event was even observed from space with auxiliary equipment onboard the
Euro-American SOHO spacecraft, a solar observatory that orbits the Sun at a
distance of 1.6 million km from Earth. The spacecraft tracked the advance of
Mercury across the Sun and broadcast it live on its
website.
The Planet Mercury
Mercury
is the nearest planet to the Sun. With a diameter of about 5000 km, it is less
than half the size of Earth, and is somewhat bigger than our Moon. Mercury also
is the fastest planet, its year (the time it takes to orbit the Sun once), is
only 88 days, but its day is 58 Earth days long!
A Coming
Spectacle
Like Mercury, Venus is closer to the Sun than
Earth, and gracefully it also passes in front of the Sun. But the transits of
Venus are very rare, recurring in periods between 105 and 121 years; and since
its orbit is considerably larger than that of Mercury. The last transit of Venus
was observed in 1882, and fortunately a transit of Venus is due, on 8 June 2004;
again Egypt will be one of the most favorable observing sites for the eagerly
anticipated spectacle!
Bibliotheca Alexandrina, the leader of an
ancient, glorious era in the history of astronomy invites you to enjoy the
coming spectacle - it""s a lifetime experience.