Archived from: Mt. Wilson Observatory Museum Exhibit:
MWO Museum Exhibit: Halley's Comet
Information originally compiled to prepare for the 1986 return of the comet.
The comet has been observered
on 27 returns in intervals of 76 years. It was last seen in 1910
and will be seen again in 1986. The head of a comet is composed
of gases and small particles, possible no larger than grains of
sand. Probably no harm would result to the Earth from colliding with a
The comet's next return is scheduled for AD 2061. The last sentence
is no longer thought to be true. Analysis of several impact
craters on the Earth show that the effects of comet collisions
can be devastating. Even near-collisions, as is thought to have
been the case in Tunguska in 1908 can cause widespread damage.
The orbit of the comet is very elliptical (e = 0.97), almost parabolic.
At closest approach, it is 0.59 A.U. from the Sun (just under 90 million km,
or 55 million miles), and its orbit extends out to beyond the planet Neptune.
A close-up image of the comet's nucleus. Note the different jets of material
that make up the beginning of the tail. The tail is blown away from the comet
by the solar wind, thus, it always points away from the Sun.
The stars in this photograph are elongated because the camera was tracking the
comet, which moved perceptibly against the background stars.
An image of the whole tail.
Text and images after: Mt. Wilson Observatory Museum Exhibition.
[Comet Halley Page]