Google+ Mars Travel: Dust Devils on Mars
Showing posts with label Dust Devils on Mars. Show all posts
Showing posts with label Dust Devils on Mars. Show all posts

Mars Photo of the Day - May 2 2012

Today's Image of Mars show three distinct dust devils in North Amazonis Planitia, as imaged by HiRISE. You can also see lighter paths along which dust devils have passed previously. This is because when dust devils pass over the dust laden ground they pick up that darker dust and expose the lighter terrain below. In areas with lighter dust covering darker terrain, just the opposite effects occur.

Click on this image to see a captioned subimage of this one from HIRISE.



Mars Photo of the Day - Apr 4 2012

Today's Image shows an enormous dust devil in Amazonis Planitia on Mars, as taken by HiRISE. The dust devil reached as high at 20km above the surface, roughly the same size as a large terrestrial tornado. 

Even though the dust devil reaches so high it only measures 70m in diameter, which allows it to be twisted by high elevation winds giving it a snake-like appearance, like a similar dust devil showcased by Mars Travel.

Dust devils on Mars are similar to tornadoes on Earth, but the biggest difference is that instead of water particles making up the visible outer layer, like in a tornado, dust and sand make up the visible layer. The dust devils on Mars are so much bigger than their counterparts on Earth because the Martian atmosphere is only about 1% as dense as that on Earth. 

Clicking on this image will take you to the original, captioned image from HiRISE. I definitely recommend checking it out since they have attached animations showing what it looks like in motion from different angles. 


Mars Photo of the Day - Mar 8 2012

Today's Image of Mars comes from HiRISE and shows the snaking shadow of a huge dust devil in Amazonis Planitia. The length of this shadow indicates that this particular dust devil is approximately 800m (half a mile) in height.

The reason that it is so serpentine is that at about 250m above the surface a westerly breeze pushed the top of the dust devil to the east. This particular dust devil is about 30m in diameter.

What is extraordinary about this dust devil is that it formed during a time of year when Mars is furthest from the Sun. Just as on Earth, the Sun plays a large role in the winds on Mars, but it seems that even when Mars is further away from the Sun, it still has numerous dust devils!

Clicking on this image will take you to the original, captioned image from HiRISE, from where you can view the high resolution images!





Mars Photo of the Day - Nov 28 2011

Today's Image of Mars is a compilation of dust devil images from Mars Exploration Rover Spirit as taken in Gusev Crater. These images were taken on Sol 543 of Spirit's mission, which was on July 12 2005. 

Gusev Crater is approximately 166km in diameter and is thought to have formed between three and four billion years ago. The crater was likely home to a lake in the distant Martian past, as Ma'adim Valles drains into it and the ground is rich with sediments that are up to 3000 feet thick. 

Images of dust devil tracks in Gusev Crater were taken from orbit and investigated by Mars Rover Spirit. There is speculation that Spirit lasted so long on Mars because dust devils helped clean its solar panels. 

Clicking this image will take you to the original, slightly larger version of this from NASA.




Hurricane Force Winds on Mars

There are some powerful winds on Mars, but just how powerful was only discovered recently. David Choi of NASA's Goddard Space Flight Center used images of dust devils taken by Mars Reconnaissance Orbiter's HiRISE camera to determine the speed of the swirling dust devils. 


Tracks Left by Dust Devils on Mars
Source: HiRISE
But just how did he do this?

Choi looked at different HiRISE images of the same dust devil and determined how far four distinct cloud features had moved from one photo to the next. Because he knew the time elapsed between each image he was able to calculate how fast the swirling dust devil was moving. 

So just how fast was the wind blowing on Mars?

Really fast. In some cases the wind speeds were 45 m/s (162 km/hr), well above 33 m/s (118.8 km/hr) which constitutes hurricane force winds on Earth. The typical wind speed was from 20-30 m/s (72-108 km/hr). 

The dust devils observed were anywhere from 30-250 meters in diameters and rose from 150-700 meters into the sky.

These findings were presented in Nantes, France on October 3 2011 to the European Planetary Science Congress and the American Astronomical Society’s Division for Planetary Sciences.

Mars Photo of the Day - Sept 29 2011

Today's Mars Photo shows an area recently crossed by numerous dust devils. Dust devils are similar to small tornadoes and are common on Mars. The dark veins are the result of dust devils picking up bright dust and exposing the darker, less dusty surface. 

The image below links the original image which has a captioned provided by the HiRISE team.