Saturday, May 9, 2009


SATURN AND HER ENCHANTING RINGS--

NASA’s Cassini spacecraft is giving scientists extraordinary glimpses of the ringed planet Saturn and its moons with the most incredible detail ever obtained. The above view was done as the unmanned spacecraft moved above the dark side of the planet.

As very little light makes it way through the rings, they appear somewhat dark compared with the reflective surface of the planet. This view combines 45 images taken over the course of about two hours according to a recent article on the British Daily Mail web site.

The spacecraft was launched from Earth in 1999 and in its first five years photographed the moon, Mars and Jupiter, only approaching Saturn in June of 2004.

That first-ever close-up study of the ringed planet which ended in June of last year provided such opportunities for exploration and discovery NASA extended it for another two years.

In the smaller photo below one of Saturn’s moons, Rhea, passes in front of the planet’s largest moon, Titan, as it is lit from behind by the sun.

Saturn is second to Jupiter in size of the nine planets including Earth that orbit our sun. It has a diameter of some 75,000 miles while the Earth is a relatively puny 7,926 miles in diameter.

While the Earth orbits the sun about 93 million miles away, Saturn is approximately 800 million miles from the sun. These numbers are given as approximations because the planets have elliptical, not round, orbits.

Ironically, Saturn is right now nicely positioned for viewing by the naked eye. High overhead and slightly to the south just after dark you can see the constellation Leo. Leo’s (The Lion) head is clearly represented by an arrangement of stars that look like a reversed question mark. It is facing west.

To the left you will see a triangle of stars that represent the lion’s rear haunches and tail. That looks like a triangle lying on its side. Extend an imaginary line downward through the stars of the triangle’s base and you will see a very bright “star”

That’s not a star at all, that’s Saturn!*

With the naked eye, or even with binoculars, you will not be able to see the rings. That takes a good telescope and at least a 50 power eyepiece. Even then, your viewing image will be quite small and the rings barely visible because they are now edge-on toward the Earth, not being seen obliquely as the spacecraft did above.

Regardless, it’s a nice experience to stand in your backyard and see a recognizable object 800 million miles out in space—with the naked eye.
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*Please see Wednesday’s blog for a celestial map.

3 comments:

The Boca Beagle said...

Terry:

FYI

First,
Atlantis and the STS-125 crew are set to launch at 2:01 pm EDT on Monday, May 11, on a mission to upgrade the Hubble Space Telescope.

The launch can be viewed on NASA Selrct TV over the Internet.

Second,
Pluto is no longer considered a planet. It is one of thousands of Plutoids orbiting in the Kuiper Belt.

So there are now only eight planets in the solar system.

Terry Wolf said...
This comment has been removed by the author.
Terry Wolf said...

Hi Bill: Great to hear from you and, yes, I am aware of the approaching Hubble repair launch.

I also am very much aware of Pluto's recent demotion to mere cosmological dust. Even though Pluto is quite Goofy in her size, shape, etc., I haven't been quite so quick to accept her humiliation.

Heavens, that's akin to learning Santa Claus is just make believe.