What is . . the transit of venus ?
The Transit of Venus The
What is a transit of venus?
Definition :: transit
- An act, process, or instance of passing through or over;
the conveyance of something from one place to another
There are nine planets in our Solar System which journey
around the Sun (note that the image below is not to scale).
The order is : sun, mercury, venus, earth, mars, jupiter,
saturn, uranus, neptune, pluto.
Venus is the second planet from the Sun while we live on
the third planet, Earth.
On 8th June 2004 a transit of venus will be observed from
Earth when Venus comes directly between the Sun and our planet
and it will be seen to move across the bright solar disk.
What will I see?
Viewed from Earth, Venus will appear as a black dot moving
slowly from left to right across the southernmost part of
the Sun’s bright disk. With a diameter of
approximately 12, 103 km, 114 Venus sized circles could fit
across the full width of the Sun.
One aspect to watch out for is the famous “black drop” effect
which can be observed just as the planet proceeds fully onto
the solar disk. This is due to the fact that light from the
Sun is bent around the planet (refracted by the atmosphere
of Venus). So at the edge of the Sun (the solar limb),Venus
appears to be slightly “larger”, giving the optical
illusion of a stretched out black drop.
How long will it last?
Well that depends where you are in the world! Not everyone
on Earth will be able to view the transit. NASA has produced
what countries will be in the path of the transit. Also,
NASA has provided information on the start
and end times of the event for many major cities across
As an example, take the location where Jeremiah Horrocks
first predicted and observed a transit of Venus on 1639 – that
is Much Hoole, near Preston, Lancashire, United Kingdom.
The transit will start at 06:19am and end
at 12:23pm having lasted
for just over 6 hours.
How can I observe it safely?
All observations that involve looking at the Sun are dangerous.
Precautions must be taken to avoid permanent eye damage.
If you are planning to observe the transit of Venus in
June 2004 then
NEVER LOOK DIRECTLY AT THE SUN WITH THE UNPROTECTED EYE – THIS
CAN CAUSE BLINDNESSWITHIN SECONDS.
NEVER OBSERVE THE SUN DIRECTLY THROUGH A TELESCOPE OR BINOCULARS
WITHOUT PROPER OPTICAL FILTERS FITTED TO PROTECT YOUR EYES.
Follow the simple rules on this website so that you
can enjoy being part of this rare astronomical event in safety.
After June 2004, when is the next transit of Venus?
You do not have to wait too long as the next transit of
Venus is in 8 years time (6th June
2012). However, after that there
will not be another one in your lifetime.
Occurrences of Transits of Venus follow an unusual pattern.
The last one was in 1882, a gap of 121 years until the event
in 2004. Then in 2012, Venus will be in transit again (8
years later). However, we are going to have to wait 105 years
until the next transit of Venus in 2117, then 2125 and then
The reason for this strange behaviour is that the journey
of Venus around the Sun (its orbit) is slightly at an angle
(or inclined) to the path that the Earth makes around the
Sun. For that reason, we do not see a transit of Venus
every time in 1.6 years that Venus comes between the Sun
and the Earth.