[petuniasevan]

Vacation Announcement

I will be on vacation from June 2nd through June 9th.
If anyone would like to volunteer to post APOD during that time, please FReepmail me.
Otherwise the APOD will not be posted as I will be visiting relatives in California.

Venus has a few similarities to Earth. It's nearly the same size, is a rocky planet, and has an atmosphere. There the similarities end.

Compare the tables below.

Venus Statistics
Mass (kg)	4.869e+24
Mass (Earth = 1)	.81476
Equatorial radius (km)	6,051.8
Equatorial radius (Earth = 1)	.94886
Mean density (gm/cm^3)	5.25
Mean distance from the Sun (km)	108,200,000
Mean distance from the Sun (Earth = 1)	0.7233
Rotational period (days)	-243.0187
Orbital period (days)	224.701
Mean orbital velocity (km/sec)	35.02
Orbital eccentricity	0.0068
Tilt of axis (degrees)	177.36
Orbital inclination (degrees)	3.394
Equatorial surface gravity (m/sec^2)	8.87
Equatorial escape velocity (km/sec)	10.36
Visual geometric albedo	0.65
Magnitude (Vo)	-4.4
Mean surface temperature	482°C
Atmospheric pressure (bars)	92
Atmospheric composition Carbon dioxide Nitrogen Trace amounts of: Sulfur dioxide, water vapor, carbon monoxide, argon, helium, neon, hydrogen chloride, and hydrogen fluoride.	96%  3+%

Earth Statistics
Mass (kg)	5.976e+24
Mass (Earth = 1)	1.0000e+00
Equatorial radius (km)	6,378.14
Equatorial radius (Earth = 1)	1.0000e+00
Mean density (gm/cm^3)	5.515
Mean distance from the Sun (km)	149,600,000
Mean distance from the Sun (Earth = 1)	1.0000
Rotational period (days)	0.99727
Rotational period (hours)	23.9345
Orbital period (days)	365.256
Mean orbital velocity (km/sec)	29.79
Orbital eccentricity	0.0167
Tilt of axis (degrees)	23.45
Orbital inclination (degrees)	0.000
Equatorial escape velocity (km/sec)	11.18
Equatorial surface gravity (m/sec^2)	9.78
Visual geometric albedo	0.37
Mean surface temperature	15°C
Atmospheric pressure (bars)	1.013
Atmospheric composition Nitrogen Oxygen Other	77% 21% 2%

This picture shows two different perspectives of Venus. On the left is a mosaic of images acquired by the Mariner 10 spacecraft on February 5, 1974. The image shows the thick cloud coverage that prevents optical observation of the planet's surface. The surface of Venus remained hidden until 1978 when the Pioneer Venus 1 spacecraft arrived and went into orbit about the planet on December 4th. The spacecraft used radar to map planet's surface, revealing a new Venus. Later in August of 1990 the Magellan spacecraft arrived at Venus and began its extensive planetary mapping mission. This mission produced radar images up to 300 meters per pixel in resolution. The right image show a rendering of Venus from the Pioneer Venus and Magellan radar images.

The above image comes from the Solarviews Venus image and movie gallery. Here's the URL for page one of seven:

http://www.solarviews.com/cap/index/venus1.html

[petuniasevan]

[RightWhale]

Some say that Venus is tectonically inert, compared to Mars. Venus has very little deep energy input anymore. Tidal forces from the sun would be strong if Venus rotated more quickly, but all Venus has is an interaction with its atmosphere and a good amount of surface heating. At depth it is quiet.

All the same, Venus is an excellent candidate for terraforming some day. It would need to be moved to an orbit farther from the sun, and it should have a good-sized moon of its own. How to do that and drive real estate agents to a marketing frenzy?

[RadioAstronomer]

Thanks for posting this one. I was at JPL in the flight control room, flying the Magellan.

An interesting note; if you look at a picture of the spacecraft, you will notice it is almost all white. You are looking at a multilayer insulation (MLI) of metalized Mylar, Dacron net, and Kapton with an outer layer of white woven quartz. The quartz is the white you see in the pics.

[BradyLS]

Great pics, petuniasevan!

Whenever I hear talk of Venus' hostile surface, I'm always reminded of the episodes of the $6 Million Man where Steve does battle with the Soviet probe that was supposed to land on Venus, but wound up wreaking havoc on Earth, instead.

You see, the lander was equipped to deal with the extreme temperatures and pressures, as mentioned above, and could move independently, so it was basically a tank that used its sampling arms to tear up anything that approached. And shooting it was supposed to be "impossible."