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Dim but Visible: Seeking Out Uranus
Space.com ^ | 03 October 2008 | Joe Rao

Posted on 10/06/2008 8:18:07 PM PDT by Excuse_My_Bellicosity

Here is a trivia question: How many planets are visible without a telescope? Most will answer "five" (Mercury, Venus, Mars, Jupiter and Saturn). Some might answer "six" and include the Earth in the mix. Six, in fact, is the correct number, but if you exclude our own world, there is indeed one other planet that can be spied without optical aid: the planet Uranus.

This week will be a fine time to try and seek it out, especially since it is now favorably placed for viewing in our evening sky and the waxing moon is not overly bright.

Of course, you'll have to know exactly where to look for it. Barely discernable by a keen naked eye on very dark, clear nights, Uranus — currently shining at magnitude +5.7 — is now visible during the evening hours among the stars of Aquarius, the Water Carrier. On this scale, larger numbers are dimmer, with magnitude 6.0 being about the dimmest object visible under ideal, dark-sky conditions.

Tilted giant

It is best to study the accompanying chart first, and then scan that region with binoculars. Using a magnification of 150 power with a telescope of at least three-inch aperture, you should be able to resolve it into a tiny, pale-green featureless disk.

Uranus, which currently lies 1.868 billion miles (3.005 billion kilometers) from the sun, has a diameter of about 31,700 miles (51,120 kilometers) and according to flyby magnetic data from Voyager 2 in 1986, has a rotation period of 17.4 hours.

At last count, Uranus has 27 moons, all lying in orbits around the planet's equator in which there is also a complex of nine narrow, nearly opaque rings, which were discovered in 1978.

Uranus likely has a rocky core, surrounded by a liquid mantle of water, methane, and ammonia, encased in an atmosphere of hydrogen and helium. A bizarre feature is how far over Uranus is tipped. Its north pole lies 98 degrees from being directly perpendicular to its orbit plane. Thus, its seasons are extreme: When the sun rises at its north pole, it stays up for 42 Earth-years; then it sets and the north pole is in darkness for 42 Earth-years.

Fortuitous find

The British astronomer Sir William Herschel discovered Uranus on March 13, 1781, noting that it was moving slowly through the constellation Gemini. Initially, however, Herschel thought he had discovered a new comet.

Soon the name of Herschel became known over all of Europe together with the news of his discovery. King George III, who loved the sciences, had the astronomer presented to him, and bestowed upon him a life pension and a residence at Slough, in the neighborhood of Windsor Castle.

Eventually it was determined that Herschel's "comet" was, in fact, a new planet. For a while, it actually bore Herschel's name. Herschel himself proposed the name Georgium Sidus — "The Star of George," after his benefactor. However, the custom of using mythological names ultimately prevailed and the new planet was finally christened Uranus. Prior to its discovery, the outermost planet was considered to be Saturn, named for the ancient god of time and destiny, but Uranus was the father of Saturn and considered the most ancient deity of all.

It probably was for all for the best. After all, if Herschel's request was granted, just think of how we might have listed the planets in order from the sun: Mercury, Venus, Earth, Mars, Jupiter, Saturn and . . . George?


TOPICS: Astronomy; Science
KEYWORDS: astronomy; moonsofuranus; ringarounduranus; science; sirwilliamherschel; uranus; williamherschel
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1 posted on 10/06/2008 8:18:07 PM PDT by Excuse_My_Bellicosity
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To: Excuse_My_Bellicosity
Dim but Visible: Seeking Out Uranus

...and knowing it from a hole in the ground...

2 posted on 10/06/2008 8:19:52 PM PDT by xjcsa (McWhatshisname-Palin 2008)
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To: Excuse_My_Bellicosity

Dim and Uranus in the title - thought this was another Barney Frank thread!


3 posted on 10/06/2008 8:20:02 PM PDT by ikka
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To: Excuse_My_Bellicosity
Does Uranus have rings ?
4 posted on 10/06/2008 8:20:05 PM PDT by kbennkc (For those who have fought for it freedom has a flavor the protected will never know F/8 Cav)
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To: Excuse_My_Bellicosity

Are you warning us about Barney Frank?


5 posted on 10/06/2008 8:20:10 PM PDT by LeonardFMason
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To: KevinDavis

Ping.


6 posted on 10/06/2008 8:20:38 PM PDT by Army Air Corps (Four fried chickens and a coke)
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To: Excuse_My_Bellicosity

Is it pronounced “Yer-anus” or “Urine-us”?


7 posted on 10/06/2008 8:20:43 PM PDT by Dilbert San Diego
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To: Excuse_My_Bellicosity

Is that pronounced “Your Anus” or “Your In Us”...?


8 posted on 10/06/2008 8:21:15 PM PDT by freebilly
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To: Excuse_My_Bellicosity

Bwaney isn’t waughing.


9 posted on 10/06/2008 8:21:35 PM PDT by hsrazorback1 (To get what you had, do what you did.)
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To: LeonardFMason
I hope their was no pork in the Bail out Bill to a Mass Space firm to send Gerbils in Space....
10 posted on 10/06/2008 8:22:27 PM PDT by taildragger (The Answer is Fred Thompson, I do not care what the question is.....)
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To: Excuse_My_Bellicosity

More discussion here:

______________________________

Hubble spots dark spot on Uranus (picture)

http://freerepublic.info/focus/f-chat/1715170/posts


11 posted on 10/06/2008 8:22:37 PM PDT by Mr. Brightside
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To: Excuse_My_Bellicosity
At last count, Uranus has 27 moons, all lying in orbits around the planet's equator in which there is also a complex of nine narrow, nearly opaque rings, which were discovered in 1978.

Sounds serious...I'd better go see a doctor.

12 posted on 10/06/2008 8:23:43 PM PDT by xjcsa (McWhatshisname-Palin 2008)
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To: hsrazorback1

I am frustrated with Barney Frank, because he said families of candidates are fair game. He said it was ok to go after Sarah’s pregnant daughter as part of the campaign. He’s shameless.

Okay, Barney, we know you and the politically correct crowd got a nice laugh about Sarah’s daughter being pregnant. What would your reaction have been if the daughter was a lesbian? Would it still be ok to go after her then? Just wondering where the politically correct boundaries are. I’m betting a lesbian daughter of a prominent Republican or conservative would be praised for the courage of coming out of the closet and all that.


13 posted on 10/06/2008 8:27:25 PM PDT by Dilbert San Diego
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To: Dilbert San Diego
Oh here we go again. Another thread of one liners about Uranus.

Who has the Uranus ping list?

14 posted on 10/06/2008 8:40:27 PM PDT by FreeReign
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To: xjcsa

Especially watch out for Klingons around Uranus.


15 posted on 10/06/2008 8:41:51 PM PDT by dfwgator
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To: dfwgator

If Uranus has asteroids, there’s a cream for that.


16 posted on 10/06/2008 8:50:44 PM PDT by Uncle Miltie (Bushonomics: Privatize Gains, Socialize Losses......."PAULSON'S THEFT")
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To: FreeReign

For those Connecticut Freepers: Your head might be in Uranus..., but your heart is in Mianus....


17 posted on 10/06/2008 9:14:46 PM PDT by freebilly
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To: hsrazorback1

You mean Elmer Fudge?


18 posted on 10/06/2008 9:17:58 PM PDT by beethovenfan (If Islam is the solution, the "problem" must be freedom.)
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To: Excuse_My_Bellicosity

If Urananus is dim, bend over in front of a mirror and shine a flashlight on it.


19 posted on 10/06/2008 9:24:21 PM PDT by MadMax, the Grinning Reaper
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To: MadMax, the Grinning Reaper
If Urananus is dim, bend over in front of a mirror and shine a flashlight on it.

You really botched that joke. Good work!

20 posted on 10/06/2008 9:30:40 PM PDT by Chunga (Vote Republican)
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