APOD: Venus Unveiled (2019 Feb 10)

Comments and questions about the APOD on the main view screen.
User avatar
APOD Robot
Otto Posterman
Posts: 3548
Joined: Fri Dec 04, 2009 3:27 am

APOD: Venus Unveiled (2019 Feb 10)

Post by APOD Robot » Sun Feb 10, 2019 5:07 am

Image Venus Unveiled

Explanation: What does Venus look like beneath its thick clouds? These clouds keep the planet's surface hidden from even the powerful telescopic eyes of Earth-bound astronomers. In the early 1990s, though, using imaging radar, NASA's Venus-orbiting Magellan spacecraft was able to lift the veil from the face of Venus and produced spectacular high resolution images of the planet's surface. Colors used in this computer generated picture of Magellan radar data are based on color images from the surface of Venus transmitted by the Soviet Venera 13 and 14 landers. The bright area running roughly across the middle represents the largest highland region of Venus known as Aphrodite Terra. Venus, on the left, is about the same size as our Earth, shown to the right for comparison.

<< Previous APOD This Day in APOD Next APOD >>

Anon

Re: APOD: Venus Unveiled (2019 Feb 10)

Post by Anon » Sun Feb 10, 2019 7:21 am

I wonder what Earth would look like under a similar radar scan. Perhaps adjusting the “color” to something more Terran like blue/green.

User avatar
Ann
4725 Å
Posts: 9516
Joined: Sat May 29, 2010 5:33 am

Re: APOD: Venus Unveiled (2019 Feb 10)

Post by Ann » Sun Feb 10, 2019 7:42 am

Anon wrote:
Sun Feb 10, 2019 7:21 am
I wonder what Earth would look like under a similar radar scan. Perhaps adjusting the “color” to something more Terran like blue/green.
Well, Earth has a very diverse surface. There are large oceans, icecaps (for now), large deserts, rain forests (for now), grasslands and urban areas. Surely Earth would look very different than Venus even in a radar image.

Ann
Color Commentator

Boomer12k
:---[===] *
Posts: 2484
Joined: Sun Apr 22, 2007 12:07 am

Re: APOD: Venus Unveiled (2019 Feb 10)

Post by Boomer12k » Sun Feb 10, 2019 7:46 am

It almost looks like a "Fractal" world...lots of swirls that swirl into smaller swirls....

interesting comparison....Life and no life...

:---[===] *

distefanom
Ensign
Posts: 62
Joined: Wed Jun 16, 2010 6:19 am

Re: APOD: Venus Unveiled (2019 Feb 10)

Post by distefanom » Sun Feb 10, 2019 11:08 am

Hi,
do Venus has surface activity? I think to Vulcan, lava flows and maybe even tectonic movements?
I think, because it's similar in size to earth, that it should have some activity of this kind...

If no...WHY do Earth has such activity? What's the difference from our planet and Venus & Mars?

User avatar
JohnD
Tea Time, Guv! Cheerio!
Posts: 1142
Joined: Wed Feb 16, 2005 2:11 pm
Location: Lancaster, England

Re: APOD: Venus Unveiled (2019 Feb 10)

Post by JohnD » Sun Feb 10, 2019 11:55 am

But the Earth is as fractal as you like. Look at any coastline, on a map or satellite photo, then from a cliff, then from the sea shore and so on. But Venus has no seas, so mountains - peaks and ridges, dropping off scree-slopes, with rough and smooth rocks, etc. If you look at a gas planet, the stripes, then swirls, then smaller details of Jupiter are just as fractal. Even a 'smoother' planet like Netune has a heirarchy of detail.

How is a "fractal" world defined?

Venus was thought to be tectonically inert today, but may have a form of tectonic activity, just not an Earth-like one https://www.sciencenews.org/article/ven ... -tectonics

John

User avatar
Ann
4725 Å
Posts: 9516
Joined: Sat May 29, 2010 5:33 am

Re: APOD: Venus Unveiled (2019 Feb 10)

Post by Ann » Sun Feb 10, 2019 1:04 pm

distefanom wrote:
Sun Feb 10, 2019 11:08 am
Hi,
do Venus has surface activity? I think to Vulcan, lava flows and maybe even tectonic movements?
I think, because it's similar in size to earth, that it should have some activity of this kind...

If no...WHY do Earth has such activity? What's the difference from our planet and Venus & Mars?
I have no idea why Venus and Earth are so different, but here is a little something that Wikipedia has to say on the subject:
Wikipedia wrote:

Without seismic data or knowledge of its moment of inertia, little direct information is available about the internal structure and geochemistry of Venus. The similarity in size and density between Venus and Earth suggests they share a similar internal structure: a core, mantle, and crust. Like that of Earth, the Venusian core is at least partially liquid because the two planets have been cooling at about the same rate. The slightly smaller size of Venus means pressures are 24% lower in its deep interior than Earth's. The principal difference between the two planets is the lack of evidence for plate tectonics on Venus, possibly because its crust is too strong to subduct without water to make it less viscous. This results in reduced heat loss from the planet, preventing it from cooling and providing a likely explanation for its lack of an internally generated magnetic field. Instead, Venus may lose its internal heat in periodic major resurfacing events.
Ann
Color Commentator

Tszabeau

Re: APOD: Venus Unveiled (2019 Feb 10)

Post by Tszabeau » Sun Feb 10, 2019 1:33 pm

I wonder if the Earth’s moon accounts for the major differences between Earth and Venus tectonic activities.

User avatar
orin stepanek
Plutopian
Posts: 4793
Joined: Wed Jul 27, 2005 3:41 pm
Location: Nebraska

Re: APOD: Venus Unveiled (2019 Feb 10)

Post by orin stepanek » Sun Feb 10, 2019 1:43 pm

Too bad we can't pull Venus into an orbit between Earth and Mars! :wink: There it would be in a moor habitable zone and we could teraform it! 8-) ( Nice to imagine) :D
Orin

Smile today; tomorrow's another day!

BDanielMayfield
Don't bring me down
Posts: 1970
Joined: Thu Aug 02, 2012 11:24 am
AKA: Bruce
Location: East Idaho

Re: APOD: Venus Unveiled (2019 Feb 10)

Post by BDanielMayfield » Sun Feb 10, 2019 2:53 pm

The solar system body Venus resembles the most is the Jovan moon Io. Of course, that's just one person's visual impression. Venus and Io probably have very little actually in common.
"Happy are the peaceable ... "

User avatar
Chris Peterson
Abominable Snowman
Posts: 14354
Joined: Wed Jan 31, 2007 11:13 pm
Location: Guffey, Colorado, USA

Re: APOD: Venus Unveiled (2019 Feb 10)

Post by Chris Peterson » Sun Feb 10, 2019 3:09 pm

Anon wrote:
Sun Feb 10, 2019 7:21 am
I wonder what Earth would look like under a similar radar scan. Perhaps adjusting the “color” to something more Terran like blue/green.
Well, the Earth was mapped using similar technology by the SRTM mission back in 2000. That produced a publicly available digital elevation model database, and lots of people have produced maps and globes from it. The topography of the ocean surface has also been used to compute the topography of the underlying ocean floor, so we have some maps showing the ocean as a smooth surface, and some showing the Earth as it would appear without its ocean. Anyway, do a search on "srtm maps" or "srtm globes" and you'll get a lot of interesting maps, color coded in different ways.
Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

sunson

Re: APOD: Venus Unveiled (2019 Feb 10)

Post by sunson » Sun Feb 10, 2019 3:15 pm

Ann wrote:
Sun Feb 10, 2019 7:42 am
Anon wrote:
Sun Feb 10, 2019 7:21 am
I wonder what Earth would look like under a similar radar scan. Perhaps adjusting the “color” to something more Terran like blue/green.
Well, Earth has a very diverse surface. There are large oceans, icecaps (for now), large deserts, rain forests (for now), grasslands and urban areas. Surely Earth would look very different than Venus even in a radar image.

Ann
Ann: I think you forgot some "for now's" ---> There are large oceans (for now), icecaps (for now), large deserts (for now), rain forests (for now), grasslands (for now) and urban areas (for now). Surely Earth...

Have a good day.

BDanielMayfield
Don't bring me down
Posts: 1970
Joined: Thu Aug 02, 2012 11:24 am
AKA: Bruce
Location: East Idaho

Re: APOD: Venus Unveiled (2019 Feb 10)

Post by BDanielMayfield » Sun Feb 10, 2019 3:32 pm

distefanom wrote:
Sun Feb 10, 2019 11:08 am
Hi,
do Venus has surface activity? I think to Vulcan, lava flows and maybe even tectonic movements?
I think, because it's similar in size to earth, that it should have some activity of this kind...

If no...WHY do Earth has such activity? What's the difference from our planet and Venus & Mars?
Earth's superiority over Venus and Mars as far as habitability is concerned is due to many factors. The most important is our planet's orbit right in the sweet spot of the Sun's habitable zone, so that Earth has been able to retain its water, and mostly in liquid form. The Earth's size has also given us a very long lived liquid outer core, which produces our protective magnetosphere and keeps tectonics and volcanic activity going. Our massive Moon has also kept Earth's tilt stable among several other benefits. Those are the three main things Earth has that Venus and Mars lack; right location, right size, and right satellite.

Bruce
"Happy are the peaceable ... "

User avatar
Chris Peterson
Abominable Snowman
Posts: 14354
Joined: Wed Jan 31, 2007 11:13 pm
Location: Guffey, Colorado, USA

Re: APOD: Venus Unveiled (2019 Feb 10)

Post by Chris Peterson » Sun Feb 10, 2019 3:39 pm

BDanielMayfield wrote:
Sun Feb 10, 2019 3:32 pm
distefanom wrote:
Sun Feb 10, 2019 11:08 am
Hi,
do Venus has surface activity? I think to Vulcan, lava flows and maybe even tectonic movements?
I think, because it's similar in size to earth, that it should have some activity of this kind...

If no...WHY do Earth has such activity? What's the difference from our planet and Venus & Mars?
Earth's superiority over Venus and Mars as far as habitability is concerned is due to many factors. The most important is our planet's orbit right in the sweet spot of the Sun's habitable zone, so that Earth has been able to retain its water, and mostly in liquid form. The Earth's size has also given us a very long lived liquid outer core, which produces our protective magnetosphere and keeps tectonics and volcanic activity going. Our massive Moon has also kept Earth's tilt stable among several other benefits. Those are the three main things Earth has that Venus and Mars lack; right location, right size, and right satellite
And the formation of the Moon from a massive collision might be what caused us to have that active liquid core, unlike Venus's similarly massive, but largely solid core.
Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

distefanom
Ensign
Posts: 62
Joined: Wed Jun 16, 2010 6:19 am

Re: APOD: Venus Unveiled (2019 Feb 10)

Post by distefanom » Sun Feb 10, 2019 3:44 pm

Hi Ann,
you quoted from Wiki:
"the lack of evidence for plate tectonics on Venus, possibly because its crust is too strong to subduct without water to make it less viscous."
can we *really* suppose that the oceans can "softer" the Earth's crust so it can subduct ?
Oceans on Earth are an average (let's say) of 8 km deep, how this can be comparable to the earth's radius which is more than 6000 km?
For me, just for a simple analogy, it's not really more than a "whetted" surface of an apple.
so how can this, be thought responsible for such planet-wide effect?
for me, instead, other effects are responsible for this *so different" appearance and behavior...
Maybe volcanoes on Venus behave differently than the one on earth. And the lack of seismology data, contributes to blur the interpretation of current data.

User avatar
Chris Peterson
Abominable Snowman
Posts: 14354
Joined: Wed Jan 31, 2007 11:13 pm
Location: Guffey, Colorado, USA

Re: APOD: Venus Unveiled (2019 Feb 10)

Post by Chris Peterson » Sun Feb 10, 2019 3:53 pm

distefanom wrote:
Sun Feb 10, 2019 3:44 pm
Hi Ann,
you quoted from Wiki:
"the lack of evidence for plate tectonics on Venus, possibly because its crust is too strong to subduct without water to make it less viscous."
can we *really* suppose that the oceans can "softer" the Earth's crust so it can subduct ?
Oceans on Earth are an average (let's say) of 8 km deep, how this can be comparable to the earth's radius which is more than 6000 km?
For me, just for a simple analogy, it's not really more than a "whetted" surface of an apple.
so how can this, be thought responsible for such planet-wide effect?
for me, instead, other effects are responsible for this *so different" appearance and behavior...
Maybe volcanoes on Venus behave differently than the one on earth. And the lack of seismology data, contributes to blur the interpretation of current data.
It's not that the oceans are changing the bulk nature of the crust. Subduction zones are all under the ocean, and the subducting material is very hydrated (e.g. clays). The water makes this crustal material more plastic. Once under pressure, water is released, forming a lubricating fluid. And water from the oceans is also carried down directly by subduction, acting as a lubricant. All of these effects depend upon water, and may be essential for subduction to occur.
Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

BDanielMayfield
Don't bring me down
Posts: 1970
Joined: Thu Aug 02, 2012 11:24 am
AKA: Bruce
Location: East Idaho

Re: APOD: Venus Unveiled (2019 Feb 10)

Post by BDanielMayfield » Sun Feb 10, 2019 8:05 pm

Chris Peterson wrote:
Sun Feb 10, 2019 3:39 pm
BDanielMayfield wrote:
Sun Feb 10, 2019 3:32 pm
distefanom wrote:
Sun Feb 10, 2019 11:08 am
Hi,
do Venus has surface activity? I think to Vulcan, lava flows and maybe even tectonic movements?
I think, because it's similar in size to earth, that it should have some activity of this kind...

If no...WHY do Earth has such activity? What's the difference from our planet and Venus & Mars?
Earth's superiority over Venus and Mars as far as habitability is concerned is due to many factors. The most important is our planet's orbit right in the sweet spot of the Sun's habitable zone, so that Earth has been able to retain its water, and mostly in liquid form. The Earth's size has also given us a very long lived liquid outer core, which produces our protective magnetosphere and keeps tectonics and volcanic activity going. Our massive Moon has also kept Earth's tilt stable among several other benefits. Those are the three main things Earth has that Venus and Mars lack; right location, right size, and right satellite
And the formation of the Moon from a massive collision might be what caused us to have that active liquid core, unlike Venus's similarly massive, but largely solid core.
Nice response. Interestingly, back when that theorized great collision very likely took place it is thought that a Venus-sized proto-Earth was hit by a Mars-sized planet. The cores of both would have combined to form our present core.

Where it not for the amount of slow release energy coming from the radioactive decay of uranium and its many daughter elements our core would have cooled off, the magnetic dynamo, tectonics and all mountain building would have stopped, and we would have lost all our water. The surface of our planet might look much like the left side of today's APOD instead of the right.

Bruce
"Happy are the peaceable ... "

User avatar
Nitpicker
Inverse Square
Posts: 2688
Joined: Fri Sep 20, 2013 2:39 am
Location: S27 E153

Re: APOD: Venus Unveiled (2019 Feb 10)

Post by Nitpicker » Sun Feb 10, 2019 11:21 pm

Anon wrote:
Sun Feb 10, 2019 7:21 am
I wonder what Earth would look like under a similar radar scan. Perhaps adjusting the “color” to something more Terran like blue/green.
I imagine it would look exactly like a topographic map of Earth (i.e. showing the elevations) with a resolution of 100 to 150m.

Here is another topographic map of Venus, with colours more typically seen on a topographic map of Earth: Edit: sorry, missed Chris's similar response, above. So you can just look at the pic in my response. :-)