(Continued from previous message)

The European Southern Observatory grew this month with the addition of its
11th member: Finland. The move gives Finland access to all ESO facilities
including the Very Large Telescope suite of four instruments in Chile, and
gives Europe an even stronger presence in the field of astronomy.

Sir Patrick Moore on the Mend

Famed British astronomer Sir Patrick Moore wasn't seen on BBC TV this
month for the first time since his SKY AT NIGHT program debuted in 1957.
According to reports from BBC News, the 81-year-old astronomer fell ill
from food poisoning. He will miss next month's SKY AT NIGHT as well as he
recovers and is expected to be released from the hospital later this week.

Mercury's Mysterious Orbit

Mercury spins on its axis three times for every two of its orbits around
the Sun. How the tiny, baked world got locked in such a spin-orbit
resonance has remained somewhat mysterious; accepted models gave the
planet a seven percent chance of orbiting the Sun the way it does. Now a
paper by Alexandre C. M. Correia (University of Aveiro, Portugal) and
Jacques Laskar (Paris Observatory) published in the June 24th issue of
NATURE makes the resonance seem more plausible.

Their research focused on long-term changes in the shape of Mercury's
orbit. New models demonstrate that over millions of years the planet's
eccentricity ranges chaotically between nearly zero (a circular orbit) and
0.45 (very distinctly elliptical). When the eccentricity of Mercury's
orbit increases, the probability of landing in a 3:2 spin-orbit resonance
increases. Assuming that the planet's eccentricity has changed this way
during the last 4 billion years, their models suggest that Mercury has
better than even odds -- 55 percent -- of locking into a 3:2 state.

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HIGHLIGHTS OF THIS WEEK'S SKY

* At dusk on Saturday evening Mercury and Mars have a close conjunction,
appearing only about 0.2 degrees apart. Use binoculars to look for them
low above the west-northwest horizon 40 or 50 minutes after sunset.
Mercury is the brighter of the two, on top.
* Delta Scorpii brightened unexpectedly in July 2000 and has remained
bright ever since. It is now high in the south after nightfall.
* New Moon on Saturday, July 17th.

For details, see This Week's Sky at a Glance and Planet Roundup:

> http://SkyandTelescope.com/observing/ataglance/

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