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Venus Express
tedstryk
post Apr 12 2005, 06:56 PM
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If all goes well, Venus Express will be a major topic for discussion in this forum a year from now. Does anyone know how good the surface coverage will be from VIRTIS and VMC? My understanding is that VIRTIS will obtain low resolution multispectral maps, and that VMC will, in addition to cloud monitoring, have one channel that can see the surface, but I don't know at what resolution or at what quality. It will be nice to have some non-radar images of Venus' surface besides the Venera snapshots and the shadowy images from Earth and Galileo's NIMS.

Ted


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RNeuhaus
post Nov 7 2005, 03:54 PM
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Besides, the other intrigating thing is that Venus sluggishly rotates on its axis once every 243 Earth days, while it orbits the Sun every 225 days - its day is longer than its year!

On the other hand, Venus rotates retrograde, or "backwards," spinning in the opposite direction of its orbit around the Sun. From its surface, the Sun would seem to rise in the west and set in the east.

The other odd thing is that its Equatorial Inclination to Orbit is 177.3 degrees. By comparison, it is: 7.56 x Earth. That is its north pole is almost pointing to the south pole.

These are at least one of the oddies things that I would like to understand:

Why does the day is longer than a year?
Why the planet rotates on backwards?

Rodolfo
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ljk4-1
post Nov 7 2005, 04:03 PM
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QUOTE (RNeuhaus @ Nov 7 2005, 10:54 AM)
Besides, the other intrigating thing is that Venus sluggishly rotates on its axis once every 243 Earth days, while it orbits the Sun every 225 days - its day is longer than its year!

On the other hand, Venus rotates retrograde, or "backwards," spinning in the opposite direction of its orbit around the Sun. From its surface, the Sun would seem to rise in the west and set in the east.

The other odd thing is that its Equatorial Inclination to Orbit is 177.3 degrees. By comparison, it is: 7.56 x Earth. That is its north pole is almost pointing to the south pole.

These are at least one of the oddies things that I would like to understand:

Why does the day is longer than a year?
Why the planet rotates on backwards?

Rodolfo
*


A whomping big celestial impact is my guess.


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"After having some business dealings with men, I am occasionally chagrined,
and feel as if I had done some wrong, and it is hard to forget the ugly circumstance.
I see that such intercourse long continued would make one thoroughly prosaic, hard,
and coarse. But the longest intercourse with Nature, though in her rudest moods, does
not thus harden and make coarse. A hard, sensible man whom we liken to a rock is
indeed much harder than a rock. From hard, coarse, insensible men with whom I have
no sympathy, I go to commune with the rocks, whose hearts are comparatively soft."

- Henry David Thoreau, November 15, 1853

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RNeuhaus
post Nov 7 2005, 04:26 PM
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QUOTE (ljk4-1 @ Nov 7 2005, 11:03 AM)
A whomping big celestial impact is my guess.
*

Interesting but...why no a moon. After an impact to Venus and that should have a moon like the Earth's case.

I thought that the Venus' slow rotation might be caused by a very heavy atmosphere that circulates the planet in the opposite side to its rotation.

Or perhaps that is a normal for physics' law since its neigboor planet Mercury rotates around 58 Earth days and orbits around the Sun 88 Earth days. That is more or less a very long day that approach to a "planet of close one year" for both Mercury (less days) and Venus (more days).

Rodolfo
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ljk4-1
post Nov 7 2005, 04:30 PM
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QUOTE (RNeuhaus @ Nov 7 2005, 11:26 AM)
Interesting but...why no a moon. After an impact to Venus and that should have a moon like the Earth's case.

I thought that the Venus' slow rotation might be caused by a very heavy atmosphere that  circulates the planet in the opposite side to its rotation.

Or perhaps that is a normal for physics' law since its neigboor planet Mercury rotates around 58 Earth days and orbits around the Sun 88 Earth days.  That is more or less a very long day that approach to a "planet of close one year" for both Mercury (less days) and Venus (more days).

Rodolfo
*


Actually, should a large impact create a moon? My guess is that if Venus did get hit by something massive and powerful enough to practically flip it over, slow down its spin rate, and have it rotate in the opposite direction of most other major worlds, Venus was lucky enough to have survived intact, forget having a moon in the outcome.

Or maybe Venus was hit BY its own moon.


--------------------
"After having some business dealings with men, I am occasionally chagrined,
and feel as if I had done some wrong, and it is hard to forget the ugly circumstance.
I see that such intercourse long continued would make one thoroughly prosaic, hard,
and coarse. But the longest intercourse with Nature, though in her rudest moods, does
not thus harden and make coarse. A hard, sensible man whom we liken to a rock is
indeed much harder than a rock. From hard, coarse, insensible men with whom I have
no sympathy, I go to commune with the rocks, whose hearts are comparatively soft."

- Henry David Thoreau, November 15, 1853

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JRehling
post Nov 7 2005, 05:26 PM
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QUOTE (ljk4-1 @ Nov 7 2005, 09:30 AM)
Actually, should a large impact create a moon?  My guess is that if Venus did get hit by something massive and powerful enough to practically flip it over, slow down its spin rate, and have it rotate in the opposite direction of most other major worlds, Venus was lucky enough to have survived intact, forget having a moon in the outcome.

Or maybe Venus was hit BY its own moon.
*


There are good sources on the Net for things being wildly speculated about here.

To pick just one: the angular momentum of a planet-moon system would remain the same after an impact as before. Such a collision couldn't make the system go backwards unless it was going backwards in the first place.

For the Moon to be created from a collision, it had to be a glancing blow. A straight-on punch would not liberate a lot of material.

A collision would be necessary if Venus's rotation was set in place as its formation concluded. But there are suggestions that tidal and thermal dynamics of its massive atmosphere may have "set" the rotation at the current rate. If so, the initial rotation is irrelevant/unknowable. In fact, the low inclination suggests that there is some sort of sun-driven factor: a collision that reordered Venus's rotation radically would be unlikely to leave the axis so nearly perpendicular to its orbit -- although that kind of coincidence is not impossible.

The rotation is only one oddity, not two or more. Given that the rotation is so slow, the reversal is not so odd -- the difference between rotating slowly E-W or slowly W-E is not nearly so big a difference as the slow rotation in the first place. Consider that a point on Venus's equator is rotating at about the speed of a fast *walk*!!! If it were moving the other direction, but just as slowly, that would only be a difference of a few km/h.

Also, the relative relationship between the day and year of Venus is not an "extra" oddity. Given the slow rotation, that follows as a logical consequence.

There is a second mystery regarding Venus's rotation, however, and that is why it is [almost] synchronized so as to show [almost] the same face towards the Earth at every conjunction. Mathematically, it would seem impossible for the tidal attraction to make this happen... but if this is a coincidence, it is a remarkable one.
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ljk4-1
post Nov 7 2005, 10:08 PM
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QUOTE (JRehling @ Nov 7 2005, 12:26 PM)
There are good sources on the Net for things being wildly speculated about here.

*


There was this guy a long time ago named Aristarchus who wildly speculated that Earth went around the Sun and that the stars were other suns very far away.

The powers that be of his era accused him of religious impiety. His ideas were effectively buried for 1,500 years.

These ideas may "just" be speculation, but they are not wild. Uranus has been thought by many sober, rational astronomers to be in its present state due to major collisions by natural objects in its past, so why not for Venus to explain its current different state?


--------------------
"After having some business dealings with men, I am occasionally chagrined,
and feel as if I had done some wrong, and it is hard to forget the ugly circumstance.
I see that such intercourse long continued would make one thoroughly prosaic, hard,
and coarse. But the longest intercourse with Nature, though in her rudest moods, does
not thus harden and make coarse. A hard, sensible man whom we liken to a rock is
indeed much harder than a rock. From hard, coarse, insensible men with whom I have
no sympathy, I go to commune with the rocks, whose hearts are comparatively soft."

- Henry David Thoreau, November 15, 1853

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imran
post Nov 9 2005, 02:41 AM
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Less than one hour from launch!

Live webcast should be here:
http://www.starsem.com
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jamescanvin
post Nov 9 2005, 03:11 AM
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QUOTE (imran @ Nov 9 2005, 01:41 PM)
Less than one hour from launch!

Live webcast should be here:
http://www.starsem.com
*


Anybody getting a feed from here yet?

Just wondering if the error message I'm getting is because it hasn't starting or if there is an incompatibilty with the OSX version of Media Player.

James


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imran
post Nov 9 2005, 03:22 AM
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Both webcasts are working now although you get better resolution from the Starsem site.
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Posts in this topic
- tedstryk   Venus Express   Apr 12 2005, 06:56 PM
- - BruceMoomaw   See my new note on the "Radar on Venus Expres...   Apr 20 2005, 10:31 AM
|- - tedstryk   Actually, VMC will have some limited capabliity to...   Apr 21 2005, 03:16 AM
- - BruceMoomaw   You've caught me -- I was completely unaware o...   Apr 21 2005, 05:34 AM
- - Mode5   To the powers that be, thank you for creating this...   Apr 21 2005, 05:53 AM
- - Gsnorgathon   Ted - do you have a link for the ESA mission doc(s...   Apr 21 2005, 07:08 AM
|- - tedstryk   http://megasn.obspm.fr/VEX_MDR51.doc It is a bit ...   Apr 21 2005, 09:17 AM
- - djellison   I wonder if the effects of looking thru narrow spe...   Apr 21 2005, 09:26 AM
- - tedstryk   Hard to tell. It is sort of like Pre-Cassini Tita...   Apr 21 2005, 09:51 AM
|- - Richard Trigaux   QUOTE (tedstryk @ Apr 21 2005, 09:51 AM)It is...   Jun 26 2005, 08:06 AM
- - BruceMoomaw   I can dig up some stuff on this for you, given a l...   Jun 23 2005, 12:06 AM
- - remcook   I believe the spectral 'windows' are much ...   Jun 25 2005, 08:28 PM
- - edstrick   My understanding is that the topographically relat...   Jun 26 2005, 07:02 AM
- - edstrick   On Cassin, the VIMS is the best instrument we coul...   Jun 26 2005, 10:31 AM
|- - Bob Shaw   QUOTE (edstrick @ Jun 26 2005, 11:31 AM)On Ca...   Jul 8 2005, 01:59 PM
|- - JRehling   QUOTE (edstrick @ Jun 26 2005, 03:31 AM)On Ca...   Jul 8 2005, 02:23 PM
|- - Gsnorgathon   I suppose it's possible, if not easy, to subtr...   Jul 9 2005, 04:10 AM
|- - JRehling   QUOTE (Gsnorgathon @ Jul 8 2005, 09:10 PM)I s...   Jul 9 2005, 05:09 AM
- - maycm   An update....though not much new information. htt...   Jul 8 2005, 12:49 PM
- - TheChemist   Venus Express arrives in Baikonur She's got i...   Aug 10 2005, 04:33 PM
|- - Bob Shaw   QUOTE (TheChemist @ Aug 10 2005, 05:33 PM)Ven...   Aug 10 2005, 07:42 PM
- - BruceMoomaw   Here's my long-promised entry on whatever I...   Aug 29 2005, 02:10 AM
- - BruceMoomaw   Two more notes: (1) The VIRTIS team is fully re...   Aug 29 2005, 02:15 AM
- - tedstryk   http://messenger.jhuapl.edu/the_mission/im...ine_f...   Sep 11 2005, 01:35 PM
|- - 4th rock from the sun   QUOTE (tedstryk @ Sep 11 2005, 02:35 PM)... ...   Sep 12 2005, 08:46 PM
|- - tedstryk   Well, I doubt there would be time-lapse images. T...   Sep 12 2005, 09:59 PM
- - mike   America will just have to make a new probe that re...   Sep 12 2005, 07:08 PM
|- - Bob Shaw   QUOTE (mike @ Sep 12 2005, 08:08 PM)America w...   Sep 12 2005, 09:04 PM
- - TheChemist   QUOTE Oh, and the thing that the ESA Press Office ...   Sep 13 2005, 11:52 AM
|- - tedstryk   QUOTE (TheChemist @ Sep 13 2005, 11:52 AM)...   Sep 13 2005, 03:01 PM
- - RNeuhaus   New update. Now it is less than 14 days from launc...   Oct 12 2005, 04:09 AM
|- - ljk4-1   Preparations for ESA's Venus Express mission p...   Oct 13 2005, 01:50 PM
- - RNeuhaus   The spacecraft Technical details Spacecraft fact...   Oct 13 2005, 02:45 PM
|- - um3k   QUOTE (RNeuhaus @ Oct 13 2005, 10:45 AM)The p...   Oct 13 2005, 03:03 PM
||- - Rakhir   QUOTE (um3k @ Oct 13 2005, 05:03 PM)I'm n...   Oct 14 2005, 08:23 AM
|- - Rakhir   QUOTE (RNeuhaus @ Oct 13 2005, 04:45 PM)The s...   Oct 13 2005, 04:03 PM
|- - RNeuhaus   QUOTE (Rakhir @ Oct 13 2005, 11:03 AM)From ht...   Oct 13 2005, 04:46 PM
|- - tedstryk   QUOTE (RNeuhaus @ Oct 13 2005, 04:46 PM)Thank...   Oct 13 2005, 05:06 PM
|- - ugordan   QUOTE (RNeuhaus @ Oct 13 2005, 06:46 PM)Thank...   Oct 13 2005, 05:09 PM
- - RNeuhaus   The problem was already solved by changing the pro...   Oct 13 2005, 06:25 PM
- - Jeff7   QUOTE (um3k @ Oct 13 2005, 10:03 AM)I'm n...   Oct 14 2005, 04:22 AM
|- - helvick   QUOTE (Jeff7 @ Oct 14 2005, 05:22 AM)I think ...   Oct 14 2005, 08:15 AM
|- - RNeuhaus   QUOTE (Jeff7 @ Oct 13 2005, 11:22 PM)I think ...   Oct 14 2005, 03:59 PM
- - RNeuhaus   According to the VE's pdf document, VE has gre...   Oct 14 2005, 04:22 PM
- - dvandorn   Your diagram shows the most common Hohmann transfe...   Oct 15 2005, 08:59 AM
- - Rakhir   Fairing Installation Today, Monday 17 October 200...   Oct 17 2005, 08:25 PM
- - RNeuhaus   New updates about Venus Express. More details abou...   Oct 19 2005, 10:30 PM
- - Rakhir   New ESA update : summary of the launch, cruise and...   Oct 21 2005, 11:03 AM
- - Adam   Delayed: http://www.esa.int/esaCP/SEM0CV3J2FE_ind...   Oct 21 2005, 06:31 PM
- - Rakhir   Venus Express preliminary investigations bring enc...   Oct 25 2005, 11:33 AM
- - SigurRosFan   Spaceflightnow Mission Status Center: Venus Expres...   Oct 26 2005, 01:27 PM
- - Rakhir   Russian space officials Monday set a Nov. 9 blasto...   Oct 31 2005, 05:21 PM
- - RNeuhaus   Strange news. The postpone of the launch was due...   Oct 31 2005, 09:23 PM
|- - Rakhir   QUOTE (RNeuhaus @ Oct 31 2005, 11:23 PM)Stran...   Oct 31 2005, 10:24 PM
- - Rakhir   Roll Out to Launch Pad http://sci.esa.int/science...   Nov 5 2005, 04:42 PM
- - Rakhir   Pre-launch sequence was executed. 2 days... http:...   Nov 6 2005, 11:24 PM
- - paulanderson   Interesting article: 'Venus Mission May Hold ...   Nov 7 2005, 01:35 AM
- - mike   If Venus is almost exactly like Earth, but much ho...   Nov 7 2005, 03:04 AM
|- - JRehling   QUOTE (mike @ Nov 6 2005, 08:04 PM)If Venus i...   Nov 7 2005, 03:41 PM
- - RNeuhaus   Besides, the other intrigating thing is that Venus...   Nov 7 2005, 03:54 PM
|- - ljk4-1   QUOTE (RNeuhaus @ Nov 7 2005, 10:54 AM)Beside...   Nov 7 2005, 04:03 PM
|- - RNeuhaus   QUOTE (ljk4-1 @ Nov 7 2005, 11:03 AM)A w...   Nov 7 2005, 04:26 PM
|- - ljk4-1   QUOTE (RNeuhaus @ Nov 7 2005, 11:26 AM)Intere...   Nov 7 2005, 04:30 PM
|- - JRehling   QUOTE (ljk4-1 @ Nov 7 2005, 09:30 AM)Act...   Nov 7 2005, 05:26 PM
|- - The Messenger   QUOTE (JRehling @ Nov 7 2005, 10:26 AM)There ...   Nov 7 2005, 05:46 PM
|- - ljk4-1   QUOTE (JRehling @ Nov 7 2005, 12:26 PM)There ...   Nov 7 2005, 10:08 PM
|- - imran   Less than one hour from launch! Live webcast ...   Nov 9 2005, 02:41 AM
||- - jamescanvin   QUOTE (imran @ Nov 9 2005, 01:41 PM)Less than...   Nov 9 2005, 03:11 AM
||- - imran   Both webcasts are working now although you get bet...   Nov 9 2005, 03:22 AM
||- - imran   0327 GMT (10:27 p.m. EDT Tues.) The Venus Express...   Nov 9 2005, 03:30 AM
|||- - imran   QUOTE (imran @ Nov 9 2005, 03:30 AM)0327 GMT ...   Nov 9 2005, 03:32 AM
||- - jamescanvin   QUOTE (imran @ Nov 9 2005, 02:22 PM)Both webc...   Nov 9 2005, 03:33 AM
||- - imran   QUOTE (jamescanvin @ Nov 9 2005, 03:33 AM)Sta...   Nov 9 2005, 03:33 AM
||- - jamescanvin   QUOTE (imran @ Nov 9 2005, 02:33 PM)LIFTOFF...   Nov 9 2005, 03:38 AM
|||- - jamescanvin   QUOTE (jamescanvin @ Nov 9 2005, 02:38 PM)OK ...   Nov 9 2005, 03:39 AM
||- - imran   0336 GMT (10:36 p.m. EDT Tues.) T+plus 3 minutes....   Nov 9 2005, 03:38 AM
|- - JRehling   QUOTE (ljk4-1 @ Nov 7 2005, 03:08 PM)The...   Nov 9 2005, 06:12 AM
- - djellison   Moons tend to orbit their parent planet in the sam...   Nov 7 2005, 04:57 PM
- - BruceMoomaw   Well, as Chesterton said, the most remarkable thin...   Nov 7 2005, 09:20 PM
- - RNeuhaus   Anyway, at the beginning of the planetary formatio...   Nov 7 2005, 09:57 PM
- - Waspie_Dwarf   Alternative link for the live webcast of the launc...   Nov 9 2005, 03:06 AM
|- - jamescanvin   QUOTE (Waspie_Dwarf @ Nov 9 2005, 02:06 PM)Al...   Nov 9 2005, 03:14 AM
- - Waspie_Dwarf   The live feed won't start until 03:28 GMT, at ...   Nov 9 2005, 03:14 AM
- - imran   Cutoff of 3rd stage and separation of nose module.   Nov 9 2005, 03:41 AM
|- - jamescanvin   QUOTE (imran @ Nov 9 2005, 02:41 PM)"Eve...   Nov 9 2005, 03:42 AM
|- - imran   QUOTE (jamescanvin @ Nov 9 2005, 03:42 AM)Thi...   Nov 9 2005, 03:43 AM
|- - imran   There goes the feed. Oh well..guess I'll have...   Nov 9 2005, 03:46 AM
|- - imran   0348 GMT (10:48 p.m. EDT Tues.) T+plus 15 minutes...   Nov 9 2005, 03:51 AM
- - elakdawalla   Argh! Is that second Fregat burn happening or...   Nov 9 2005, 05:02 AM
|- - jamescanvin   From Spaceflightnow.com 0514 GMT (12:14 a.m. EST)...   Nov 9 2005, 05:16 AM
|- - Bricktop   From http://sci.esa.int/science-e/www/object/in......   Nov 9 2005, 05:19 AM
- - jamescanvin   Fregat burn should be underway by now. No word on...   Nov 9 2005, 05:06 AM
- - Waspie_Dwarf   QUOTE (jamescanvin @ Nov 9 2005, 05:16 AM)Fro...   Nov 9 2005, 05:20 AM
- - Rakhir   From http://sci.esa.int/science-e/www/object/in......   Nov 9 2005, 05:20 AM
- - Waspie_Dwarf   QUOTE (Bricktop @ Nov 9 2005, 05:19 AM)From h...   Nov 9 2005, 05:22 AM
- - jamescanvin   Hurrrah! Venus here we come   Nov 9 2005, 05:25 AM
- - elakdawalla   This from Daniel Fischer: "Just to report tha...   Nov 9 2005, 05:48 AM
- - Rakhir   MET: +02h 40m Sun acquisiton and successfully depl...   Nov 9 2005, 06:17 AM
- - Decepticon   QUOTE Venus Orbit Insertion on April 11, 2006....   Nov 9 2005, 07:03 AM
- - edstrick   "Sun acquisiton and successfully deployment o...   Nov 9 2005, 07:06 AM
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