Photo of the Week. Planet Earth. Is there anything
else like us? (Torres del Paine National Park, Chile, Patagonia,
photo courtesy of Lauren Brewer, with thanks. See full resolution.)
Astronomy news for the two weeks starting Friday, June 17,
2016.
The next skylights will appear July 1.
The Moon starts off toward the end of its waxing gibbous phase, which abruptly ends at full Moon the morning of Monday, June 20,
about the time of Moonset in North America. It then reverses
itself in the waning gibbous phase,
which terminates at last quarter on
Monday the 27th, after which we see it as a waning crescent. The night of Friday the
17th, the Moon will shine to the northeast of Mars and to the
northwest of Saturn, above
the line that connects the two planets and above Antares in Scorpius. The following night the Moon will appear
just to the left of the ringed planet, the Moon, Saturn, and
Antares falling into a nice line.
Jupiter,
well to the west as the sky darkens, sets shortly before 1 AM
Daylight Time as we open our fortnight and about midnight as we
conclude. The Big Show is off to the south, where in mid-evening
we can see astonishingly bright Mars (though fading, still nearly
as bright as Jupiter) followed by Saturn to the east and Antares
down below. It's a remarkable sight, especially in a dark sky,
which allows one to see Scorpius and the Milky Way. Be sure to note the strong
color contrast between the yellow-white Jupiter/Saturn pair and
reddish Mars. The color of the two giant planets comes from
reflection of sunlight off ammonia clouds floating in a hydrogen-
helium atmosphere loaded with hydrocarbons, whereas Mars's color
comes largely from iron oxide: rust. The group begins to set
around 3 AM.
At 5:34 PM CDT (6:34 EDT, 4:34 MDT, 3:34 PDT) on Monday, June 20,
the
Sun passes the Summer
Solstice, when and where it is as far to the north as it can
get, 23.4 degrees north of the celestial
equator. On that day the Sun rises and sets as far to the
north of east and west as possible, is overhead at the Tropic of
Cancer, and the midnight Sun stretches as far to the south of the
North Pole as the Arctic Circle. In the northern hemisphere,
daylight hours are longest and night is shortest. The Sun
thereafter begins its slow trek to the south toward the Autumnal Equinox, which it will
pass on the first day of autumn.
With the Sun at the Summer Solstice, the Winter Solstice will
cross the celestial meridian to the
south at local midnight, the main figure of Sagittarius to the east (the Solstice within its
border) and Scorpius to the west. North of Scorpius stands great
Ophiuchus, the Serpent Bearer,
while farther north we find Hercules, who needs no introduction and who stands
between orange Arcturus (to the
south as the sky darkens) and almost-as-bright Vega to the northeast. To the right of
the Hero is the charming semi-circular pattern of Corona Borealis, the Northern Crown.
