MAINE SKIES

Water possibly not as scarce in solar system as once thought

Posted April 30, 2014, at 10:02 a.m.
Last modified April 30, 2014, at 2:29 p.m.

On Oct. 15, 1998, the Cassini-Huygens spacecraft was launched as a joint effort of NASA and the European Space Agency. It was, at over two tons, one of the biggest and most complex spacecraft ever built.

It consisted of a planetary orbiter (Cassini) and an atmospheric probe/lander (Huygens). Its primary mission was a study of Saturn, but it also did flybys of Venus (1998) and Jupiter (2000) before going into orbit around the ringed planet on July 1, 2004.

The Huygens lander descended to the surface of Titan, Saturn’s major moon, on July 14, 2005, making it the first landing ever accomplished in the outer solar system. It sent back large amounts of data, including the surprising fact that Titan is thought to harbor a large body of water beneath its surface, leading to speculation that it may be the leading candidate for life in the solar system other than Earth.

Now Cassini is making the news with the announcement on April 3, 2014, that a minor moon, Enceladus, also has a body of water, about the size of Lake Superior, sandwiched between miles of surface ice and a rocky core. Water, it is beginning to appear, is not as scarce a commodity in the solar system as once thought. Cassini will continue to study the rings and surface of Saturn until the end of its functional life in 2017.

Focus on the planets

Mercury rises in the northwest at dusk, but will be difficult to spot until mid-month, when it is at its highest for the year and does not set until two hours after the sun.

Venus rises nearly two hours before the sun in May and sparkles on the eastern horizon until a half hour before sunrise. Look for a close meeting on May 25 between Venus and the crescent moon in the east an hour before sunrise.

Mars was closest to Earth in April and is now receding rapidly, with the result that both its brightness and size is diminishing. On May 10, Mars is close to and to the left of the nearly full moon, and telescopes will still reveal features such as the white polar cap.

Jupiter is still brighter and larger than any other planet as it rises high in the west an hour after sunset. Surface features are still prominent and the four major moons continue to put on a display. Jupiter remains in the sky until 1 a.m. as May opens but sets around 11 p.m. by month’s end.

Saturn rises in the southeast at sunset, is highest after midnight, and sets just before sunrise. It is near its peak brightness for 2014 in May and the ring tilt allows for seeing them in close detail. Titan and some smaller moons are also visible with a moderately powerful telescope.

Uranus is extremely dim but its blue-green disk may be spotted very near Venus on May 15.

Neptune rises in the southeast about three hours before the sun but its blue-gray disk will be hard to spot even with a powerful telescope.

May events

1 Sunrise, 5:26 a.m.; sunset, 7:40 p.m. Aldebaran, the “Red Eye of the Bull,” is just below the crescent moon about an hour after sunset tonight. This is May Day or Beltane, a cross-quarter day marking the midpoint between the spring equinox and summer solstice.

3 Brilliant Jupiter towers above the moon on the western horizon as darkness falls.

6 This is the peak night for the Eta Aquarid meteor shower derived from Halley’s comet. The 2013 display produced an exceptional display of about 140 meteors per hour, but viewers this year can expect up to 40 per hour after the moon sets around 1:30 a.m. The moon is at apogee, or farthest distance from Earth.

7 First quarter moon, 11:16 p.m.

10 Astronomy Day. Celebrate by checking out Mars in the southeast, just to the lower left of the moon about an hour after sunset.

13 Look for golden Saturn, which is now in view all night, just to the lower left of the moon an hour after sunset.

14 The sun enters Taurus on the ecliptic. Full moon, 3:18 p.m. The full moon of May is the Flower Moon and is also called the Milk Moon and Corn Planting Moon.

18 The moon is at perigee or closest approach to Earth today.

21 The sun enters the astrological sign of Gemini; however, astronomically is still in Taurus. Moon in last quarter, 9 a.m.

25 A thin crescent moon lies just above brilliant Venus on the eastern horizon an hour before sunrise.

28 New moon, 2:43 p.m.

31 Jupiter is to the upper right of the moon an hour after sunset with Mercury, all but invisible, far to the moon’s lower right. Sunrise, 4:53 a.m.; sunset, 8:13 p.m.

Send astronomical queries to Clair Wood at cgmewood@aol.com.

 

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