Eclipses of the Sun
ATLAS OF THE UNIVERSE
SOLAR ECLIPSES, 2003–2010
Date Type Duration % eclipsed Area
(if total or annular) (if partial)
min. sec.23 Nov 2003 T 1 57 – Antarctic
19 Apr 2004 P – 74 Antarctic
14 Oct 2004 P – 93 Arctic
8 Apr 2005 T 0 42 – Pacific America, northern
S. America
3 Oct 2005 A 4 32 – Atlantic, Spain, Africa,
Indian Ocean
29 Mar 2006 T 4 07 – W. and N. Africa, Turkey,
Central Asia
22 Sep 2006 A 7 09 – northern S. America,
S. Atlantic
19 Mar 2007 P – 39 E. Asia
11 Sep 2007 P – 70 southern S. America,
Antarctic
7 Feb 2008 A 2 12 S. Pacific, Antarctic
1 Aug 2008 T 2 27 – N. Canada, Greenland
Siberia, China
26 Jan 2009 A 7 54 – Indonesia, Indian Ocean
22 Jul 2009 T 6 39 – India, China
15 Jan 2010 A 11 08 – Central Africa, India, China
Indian Ocean
11 Jul 2010 T 5 20 – S. Pacific, Easter Islandare known as the nodes, so that to produce an eclipse
the Moon must be at or very near a node. Because of the
gravitational pull of the Sun, the nodes shift slowly but
regularly. After a period of 18 years 11.3 days, the Earth,
Sun and Moon return to almost the same relative positions,
so that a solar eclipse is likely to be followed by another
eclipse 18 years 11.3 days later – a period known as
the Saros. It is not exact, but it was good enough for
ancient peoples to predict eclipses with fair certainty.
For example, the Greek philosopher Thales is said to have
forecast the eclipse of 25 May 585 BC, which put an abrupt
end to a battle being fought between the armies of King
Alyattes of the Lydians and King Cyraxes of the Medes;
the combatants were so alarmed by the sudden darkness
that they made haste to conclude peace.
From any particular point on the Earth’s surface, solar
eclipses are less common than those of the Moon. This is
because to see a solar eclipse, the observer has to be in
just the right place at just the right time, whereas a lunar
eclipse is visible from any location where the Moon is
above the horizon. England had two total eclipses during
the 20th century, those of 29 June 1927 and 11 August- The track of the 1927 eclipse crossed North
England, but at the ‘return’ at the end of the Saros (9 July
- the track missed England altogether, though it
crossed Canada, Greenland and North Europe. The 11
August 1999 total eclipse crossed the Scilly Isles, Corn-
wall, South Devon and Alderney, and thence across Europe.
The main phenomena seen during totality are the
chromosphere, the prominences and the corona. The chro-
mosphere is from 2000 to 10,000 kilometres (1250 to
6250 miles) deep, with a temperature which reaches 8000
degrees C at an altitude of 1500 kilometres (950 miles)
and then increases rapidly until the chromosphere merges
with the corona. Prominences – once, misleadingly, called
Red Flames – are masses of red, glowing hydrogen.
T
he Moon moves round the Earth; the Earth moves round
the Sun. Therefore, there must be times when the three
bodies line up, with the Moon in the mid position. The
result is what is termed a solar eclipse, though it should
more properly be called an occultation of the Sun by the
Moon.
Eclipses are of three types: total, partial and annular.
At a total eclipse the photosphere is completely hidden, and
the sight is probably the most magnificent in all Nature.
As soon as the last segment of the bright disk is covered,
the Sun’s atmosphere flashes into view, and the chromo-
sphere and corona shine out, together with any prominences
which happen to be present. The sky darkens sufficiently
for planets and bright stars to be seen; the temperature falls
sharply, and the effect is dramatic by any standards. Unfort-
unately, total eclipses are rare as seen from any particular
locality. The Moon’s shadow can only just touch the Earth,
and the track of totality can never be more than 272 kilo-
metres (169 miles) wide; moreover, the total phase cannot
last more than 7 minutes 31 seconds, and is generally shorter.
To either side of the main cone of shadow the eclipse
is partial, and the glorious phenomena of totality cannot be
seen; many partial eclipses are not total anywhere. Finally
there are annular eclipses, when the alignment is perfect
but the Moon is near its greatest distance from Earth; its
disk is not then large enough to cover the photosphere
completely, and a ring of sunlight is left showing round
the dark mass of the Moon (Latin annulus, a ring).
For obvious reasons, a solar eclipse can happen only
when the Moon is new, and thus lies on the Sun-side of
the Earth. If the lunar orbit lay in the same plane as that
of the Earth, there would be an eclipse every month, but in
fact the Moon’s orbit is tilted at an angle of just over five
degrees, so that in general the New Moon passes unseen
either above or below the Sun in the sky.
The points at which the Moon’s orbit cuts the ecliptic▼ The Moon’s shadow is
divided, like any other, into
two regions, the dark central
‘umbra’, and the lighter
‘penumbra’, within which
part of the Sun remains
visible. A total eclipse of the
Sun occurs when the Earth
passes into the shadow cast
by the Moon. However, the
eclipse only appears total
from the limited region of
the Earth’s surface which is
covered by the umbra; from
inside the penumbra the
eclipse is partial. An annular
eclipse occurs when the
Moon is near apogee, and its
shadow cone does not reach
the Earth. The angular size
of the Moon as seen from
Earth is therefore too small
to cover the Sun’s disk,
so that a thin ring of light
remains visible around the
black disk of the Moon.Total solar eclipsePenumbraUmbraEarthMoonSunAnnular solar eclipseE Atl of Univ UK page 160 23/4/03 5:09 pm Page 160