APOD: Olympus Mons: Largest Volcano in the... (2023 Apr 04)

[APOD Robot]

Olympus Mons: Largest Volcano in the Solar System

Explanation: The largest volcano in our Solar System is on Mars. Although three times higher than Earth's Mount Everest, Olympus Mons will not be difficult for humans to climb because of the volcano's shallow slopes and Mars' low gravity. Covering an area greater than the entire Hawaiian volcano chain, the slopes of Olympus Mons typically rise only a few degrees at a time. Olympus Mons is an immense shield volcano, built long ago by fluid lava. A relatively static surface crust allowed it to build up over time. Its last eruption is thought to have been about 25 million years ago. The featured image was taken by the European Space Agency's robotic Mars Express spacecraft currently orbiting the Red Planet.

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[thearborist]

Curious: Near the center of Olympus Mons is what appears to be bombardment craters. Although it looks like a crater caldera, it appears more likely to be a series of strikes, perhaps from a 'string of pearls' hit by a shattered asteroid. Am I correct?

[George]

“the slopes of Olympus Mons typically rise only a few degrees *at a time*”??

[De58te]

Wow I have never seen such a clear picture of Olympus Mons.
This raises a question. I can see that it would be easy to climb the slopes starting at 12 to 1 o'clock, and then again at 3 to 4 o'clock but what about between 7 to 10 o'clock. There seems to be shear vertical cliffs maybe more than a thousand feet high! What caused the liquid lava flow to stop at the cliffs and not plummet over? (Although the lava did appear to flow over the cliffs in two places around 7:30 and again at 8:30.)

[Spif]

> Its last eruption is thought to have been about 25 million years ago.

That's pretty recent!

The Dinosaurs were long dead.

The planet was 4B years old and Olympus Mons was still erupting?

[AVAO]

Wow I have never seen such a clear picture of Olympus Mons.
This raises a question. I can see that it would be easy to climb the slopes starting at 12 to 1 o'clock, and then again at 3 to 4 o'clock but what about between 7 to 10 o'clock. There seems to be shear vertical cliffs maybe more than a thousand feet high! What caused the liquid lava flow to stop at the cliffs and not plummet over? (Although the lava did appear to flow over the cliffs in two places around 7:30 and again at 8:30.)

...also very cool panorama...

very biggggg: https://live.staticflickr.com/65535/519 ... 19fe_o.jpg
Olympus Mons - Image taken by Hope probe (Emirates Mars mission) - date : march 13th 2021
Credit : Emirates Mars mission/EXI/Thomas Thomopoulos

[Wol]

So Earth's TALLest volcano, at 10,000m, is almost the same size as Olympus Mons? Earth's HIGHest mountain is only 4000m TALL. And where and how does "largest" fit into the picture?

Or do you mean that Olympus Mons is, at three times Everest's 8000m height, actually SIX times Everest's 4000m TALLness? Which makes it not much more than twice as tall as earth's tallest volcano, Hawaii.

Cheers,
Wol

[johnnydeep]

“the slopes of Olympus Mons typically rise only a few degrees *at a time*”??

Yeah, a poor choice of words. From the WikiPedia article:

Being a shield volcano, Olympus Mons has a very gently sloping profile. The average slope on the volcano's flanks is only 5%.[15] Slopes are steepest near the middle part of the flanks and grow shallower toward the base, giving the flanks a concave upward profile. Its flanks are shallower and extend farther from the summit in the northwestern direction than they do to the southeast. The volcano's shape and profile have been likened to a "circus tent" held up by a single pole that is shifted off center.[19]

So, a 5% slope would equate to an incline angle from horizontal of 1/20 of 90 degrees, or 4.5 degrees. (Assuming that a 50% slope is 45 degrees, etc.)

[Chris Peterson]

“the slopes of Olympus Mons typically rise only a few degrees *at a time*”??

Yeah, a poor choice of words. From the WikiPedia article:

Being a shield volcano, Olympus Mons has a very gently sloping profile. The average slope on the volcano's flanks is only 5%.[15] Slopes are steepest near the middle part of the flanks and grow shallower toward the base, giving the flanks a concave upward profile. Its flanks are shallower and extend farther from the summit in the northwestern direction than they do to the southeast. The volcano's shape and profile have been likened to a "circus tent" held up by a single pole that is shifted off center.[19]

So, a 5% slope would equate to an incline angle from horizontal of 1/20 of 90 degrees, or 4.5 degrees. (Assuming that a 50% slope is 45 degrees, etc.)

Percentage slope is rise over run. So the angle is just the inverse tangent of the slope. A 5% slope corresponds to 2.86°. It's unlikely you'd easily notice that when walking, or that you'd think you were anyplace other than a flat plain visually.

[orin stepanek]

Second smallest planet in solar system has largest Volcano! Way to
go Mars !

[rstevenson]

Wow I have never seen such a clear picture of Olympus Mons.
This raises a question. I can see that it would be easy to climb the slopes starting at 12 to 1 o'clock, and then again at 3 to 4 o'clock but what about between 7 to 10 o'clock. There seems to be shear vertical cliffs maybe more than a thousand feet high! What caused the liquid lava flow to stop at the cliffs and not plummet over? (Although the lava did appear to flow over the cliffs in two places around 7:30 and again at 8:30.)

On this NASA page https://www.nasa.gov/mission_pages/MRO ... 12992.html they say that the cliffs can be as high as 7km (about 23,000’), and that it’s not clear how they formed.

Rob