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 Post subject: Venus...visible with the naked eye
Unread postPosted: Thu Aug 06, 2009 10:50 am 
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The Brightest Planet

It is visible with the naked eye in the southern skies of Africa and I'm sure for many other continents, in South Africa you can spot it in the eastern sky from as early as 7:15 pm and looks like a bright shining star.

Venus and Earth are similar in size, mass, density, composition, and distance from the sun and that is about it in comparison.

Venus is covered by a thick & rapidly spinning atmosphere, creating a world with temperatures hot enough to melt lead and a surface pressure 90 times that of Earth. Because of its proximity to Earth and the way its clouds reflect sunlight, Venus appears to be the brightest planet in the sky.

Like Mercury, Venus can be seen periodically passing across the face of the sun using a telescope and with the correct attachments in place to protect a person/s eye sight. These transits occur in pairs, with more than a century separating each pair and have been observed on 6 occasions according to my knowledge, approximate calculations reakon it will be visible again in June 2012.

Toxic Atmosphere

Venus's atmosphere consists mainly of carbon dioxide, with clouds of sulfuric acid droplets and only trace amounts of water have been detected in it's atmosphere. The thick atmosphere allows the sun's heat to enter but does not release it, resulting in surface temperatures over 880 degrees Fahrenheit (470 degrees Celsius). Probes that have landed on Venus have not survived more than a few hours before being destroyed by the incredibly high temperatures.

The Venusian year (orbital period) is about 225 Earth days long, while the planet's rotation period is 243 Earth days, making a Venus day about 117 Earth days long. Venus rotates retrograde (east to west) compared with Earth's prograde (west to east) rotation. As Venus moves forward in its solar orbit while slowly rotating "backwards" on its axis, the cloud-level atmosphere zips around the planet in the opposite direction from the rotation every four Earth days, driven by constant hurricane-force winds. How this atmospheric "super rotation" forms and is maintained continues to be a topic of scientific investigation.

About 90 percent of the surface of Venus appears to be recently solidified basalt lava; it is thought that the planet was completely resurfaced by volcanic activity 300 million to 500 million years ago.

Sulfur compounds, possibly attributable to volcanic activity, are abundant in Venus's clouds. The corrosive chemistry and dense, moving atmosphere cause significant surface weathering and erosion. Radar images of the surface show wind streaks and sand dunes. Craters smaller than 0.9 to 1.2 miles (1.5 to 2 kilometers) across do not exist on Venus, because small meteors burn up in the dense atmosphere before they can reach the surface.

Geological Features

More than a thousand volcanoes or volcanic centers larger than 12 miles (20 kilometers) in diameter dot the surface of Venus. Volcanic flows have produced long, sinuous channels extending for hundreds of kilometers.

Venus has two large highland areas: Ishtar Terra, about the size of Australia, in the north polar region, and Aphrodite Terra, about the size of South America, straddling the equator and extending for almost 6,000 miles (10,000 kilometers). Maxwell Montes, the highest mountain on Venus and comparable to Mount Everest on Earth, is at the eastern edge of Ishtar Terra.

Venus has an iron core about 1,200 miles (3,000 kilometers) in radius. Venus has no global magnetic field; though its core iron content is similar to that of Earth, Venus rotates too slowly to generate the type of magnetic field that Earth has.

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 Post subject: Re: Venus...visible with the naked eye
Unread postPosted: Thu Aug 06, 2009 7:04 pm 
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At present from South Africa , Venus is the "Morning Star" , and it is well up in the early morning , say from 2 or 3 am , and very visable because of it's proximity until sunrise , and even after that - if you can focus your eyes at the spot .

Saturn is also close ( since last year ) and very visable all night - being an outer planet from us . And a couple of the others too .

Nice Photo of Venus , Bentley , as it not only a sickle but almost full .
They say that children whose corneas are still perfect (unlike us adults) can see and describe venus with the naked eye (ie. no optics) . And now would be thew perfect time .


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 Post subject: Re: Venus...visible with the naked eye
Unread postPosted: Fri Aug 07, 2009 9:53 am 
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They say that children whose corneas are still perfect (unlike us adults) can see and describe venus with the naked eye (ie. no optics)


:big_eyes: I wish I could...star gazing without optics :hmz: .
Your comments about Saturn are also very true, with the naked eye it gives off a pale pastel greenish-yellow colour. Looking at it with a scope is also something else - it looks like a high definition picture stuck up in the sky, the rings surrounding the planet made up of meteors, dust and ice.
:thumbs_up:

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 Post subject: Re: Venus...visible with the naked eye
Unread postPosted: Fri Aug 07, 2009 10:54 am 
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Last night Jupiter moved in conjunction with the 1 day old almost Full Moon through the night sky . They were very close to each other and Jupiter was very bright .


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 Post subject: Re: Venus...visible with the naked eye
Unread postPosted: Fri Aug 07, 2009 11:07 am 
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Interesting facts bentley!! :thumbs_up: :thumbs_up:


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 Post subject: Re: Venus...visible with the naked eye
Unread postPosted: Fri Aug 07, 2009 6:53 pm 
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:wink: Only a pleasure, not totally clued up as yet but will share the bits 'n pieces as I go along :thumbs_up:

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 Post subject: Re: Venus...visible with the naked eye
Unread postPosted: Thu Aug 13, 2009 1:48 pm 
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bentley wrote:
It is visible with the naked eye in the southern skies of Africa and I'm sure for many other continents


Nice post bentley. I just thought I'd make a quick comment on the above. Venus is indeed visible to the naked eye from South Africa and many other continents. In fact, it is visible to the naked eye from most locations on earth (with some exceptions, I'll get to that just now).

I'm not sure what you mean by "in the southern skies of Africa" but in southern Africa (or anywhere in the southern hemisphere) Venus will be visible in the northern skies. That is because, even though Venus does not have a fixed position in the sky (being a planet, not a star), it will always be situated on or very close to the ecliptic plane. If you can visualise the solar system the ecliptic plane is the plane in which all of the planets' orbits lay. All the orbits aren't exactly in the same plane but they're quite close and the ecliptic is defined as the plane in which earth's orbit lays.

For this reason, the sun follows the ecliptic plane through the sky and Venus, the other planets and any object that orbits the sun close to that same plane will move through the sky near the same line that the sun is tracing.

In the southern hemisphere (at least south of the Tropic of Capricorn) the sun (and Venus) will always follow an arc through the northern skies while in the northern hemisphere (north of the Tropic of Cancer) the sun (and Venus) will always follow an arc through the southern skies.

Finally, there are some locations and times when Venus is not visible.
1. For the same reason that the sun is not visible north of the arctic circle or south of the antarctic circle at certain times of the year, Venus will also not be visible.
2. Venus orbits the sun at a different speed than us which means that at times it appears to be far from the sun while at other times it appears to be very close to the sun. In fact, from time to time Venus moves directly in front of the sun. When Venus is very close to the sun (near conjunction or opposition) it is not visible to the naked eye. This is because the sunlight is just too bright and, like we can't see other stars we can also not see Venus but also because Venus goes through phases like the moon and when it is at conjunction we only see the dark side of Venus.

Lots of rambling but what I wanted to say is:
1. Venus is indeed visible to the naked eye from every location on earth but not at all times.
2. Venus is visible in the northern skies if viewed from southern Africa.

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 Post subject: Re: Venus...visible with the naked eye
Unread postPosted: Fri Aug 14, 2009 9:35 am 
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:thumbs_up: Hit the nail on the head there Deefstes...
Your assumption of rambling is actually very interesting & many points taken in on my side :wink:

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