Featured Research

from universities, journals, and other organizations

Rounded stones on Mars evidence of flowing water

Date:
May 30, 2013
Source:
University of Copenhagen - Niels Bohr Institute
Summary:
Observations by NASA's Mars rover Curiosity have revealed areas with gravel and pebbles that are characteristic of a former riverbed. Researchers have analyzed their shapes and sizes and the rounded pebbles clearly show that there has been flowing water on Mars.

The study area, which has been named 'Hottah', is by all accounts the remains of sediments from the bottom of an ancient stream, which had a relatively strong current.
Credit: Malin Space Science Systems

Observations by NASA's Mars rover Curiosity have revealed areas with gravel and pebbles that are characteristic of a former riverbed. Researchers, including members of the Niels Bohr Institute, have analysed their shapes and sizes and the rounded pebbles clearly show that there has been flowing water on Mars. The results are published in the scientific journal, Science.

The Mars rover's stereo camera took pictures of a few areas with densely packed pebbles, cemented together like concrete. The image field of an area named Hottah was a mosaic of approximately 1.4 meters x 80 centimeters. But when the picture is taken at an angle from the camera arm's two meter high mast down towards the ground-level, it gives a slightly distorted view in which the size of the rocks depend on their location in the image frame. To remedy this, the researcher first had to process the image so the proportions are comparable.

"Next, we divided the image into smaller fields of 10 mm and analysed the gravel, which consists of coarse grains of sand around 1/3 mm. We examined the pebbles which are between 4 and 40 mm in greater detail. Altogether we made a thorough analysis of 515 pebbles," explains Asmus Koefoed, a research assistant in the Mars Group at the Niels Bohr Institute at the University of Copenhagen.

Smooth, rounded stones

When rocks are worn by the wind, they become angular and rough -- similar to the result of sandblasting. When rocks are moving in flowing water, they are worn down in a completely different way. They tumble around in a mixture of water and sand bumping into each other and the corners and edges of the rocks eventually become smooth and rounded.

"We could see that almost all of the 515 pebbles we analysed were worn flat, smooth and round. We have classified them according to their geometry, which can be described using a single number -- the 'Corey shape factor', where 0 describes rocks that are completely flat like a piece of paper and 1 means they are perfect spheres," explains Asmus Koefoed.

There are both light and dark rocks in various shades and colours -- much like the original rocks on Earth and Mars. Densely packed deposits were formed locally, which occur when fine sand and mud flow along with the gravel and pebbles. This all clumps together into something that can harden into a concrete-like substance, a conglomerate. The solid sediments have then subsequently been worn flat on the top by wind-borne sand particles that flowed past the conglomerate during events of very strong wind.

Current like a Danish stream

The new results are interesting because they tell us about the climate history of Mars. What would it take to cause the stones to look like they do?

"In order to have moved and formed these rounded pebbles, there must have been flowing water with a depth of between 10 cm and 1 meter and a flow rate of about 1 meter per second -- or 3.6 km/h -- slightly faster than a typical natural Danish stream," explains Morten Bo Madsen, head of the Mars research group at the Niels Bohr Institute.

So it has not just been sporadic flowing water that evaporates quickly, but prolonged warmer periods where the streams were active. There was probably a higher atmospheric pressure on the planet than today, where the pressure is below about 1000 Pascal, about one percent of the Earth's atmospheric pressure. This means that the planet must have had a denser atmosphere, which caused a greater surface pressure than today.

Until now, it was believed that the warm period on mars was as far back as 3.5-3.7 billion years ago, but with the new studies it is now believed that this period may have extended to only 2-3 billion years ago.

Mars has thus been a dynamic place, which would not have been totally inhospitable to life, as we know it on Earth. Apart from running water recent investigations with Curiosity have shown that there were a pH-neutral environment and minerals that microbial life could use for nourishment.

Curiosity has thus achieved one of its objectives, namely to investigate whether there are areas on Mars, which could have been habitable for microbial life.


Story Source:

The above story is based on materials provided by University of Copenhagen - Niels Bohr Institute. Note: Materials may be edited for content and length.


Journal Reference:

  1. R. M. E. Williams et al. Martian Fluvial Conglomerates at Gale Crater. Science, 2013; 340 (6136): 1068 DOI: 10.1126/science.1237317

Cite This Page:

University of Copenhagen - Niels Bohr Institute. "Rounded stones on Mars evidence of flowing water." ScienceDaily. ScienceDaily, 30 May 2013. <www.sciencedaily.com/releases/2013/05/130530142011.htm>.
University of Copenhagen - Niels Bohr Institute. (2013, May 30). Rounded stones on Mars evidence of flowing water. ScienceDaily. Retrieved October 1, 2014 from www.sciencedaily.com/releases/2013/05/130530142011.htm
University of Copenhagen - Niels Bohr Institute. "Rounded stones on Mars evidence of flowing water." ScienceDaily. www.sciencedaily.com/releases/2013/05/130530142011.htm (accessed October 1, 2014).

Share This



More Space & Time News

Wednesday, October 1, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

French Apple Fans Discover the Apple Watch

French Apple Fans Discover the Apple Watch

AFP (Sep. 30, 2014) — Apple fans in France discover the latest toy, the Apple Watch. The watch comes in two sizes and an array of interchangeable, fashionable wrist straps. Duration: 00:42 Video provided by AFP
Powered by NewsLook.com
The Water You Drink Might Be Older Than The Sun

The Water You Drink Might Be Older Than The Sun

Newsy (Sep. 27, 2014) — Researchers at the University of Michigan simulated the birth of planets and our sun to determine whether water in the solar system predates the sun. Video provided by Newsy
Powered by NewsLook.com
First Woman Cosmonaut in 17 Years Blasts Off for ISS

First Woman Cosmonaut in 17 Years Blasts Off for ISS

AFP (Sep. 26, 2014) — A Russian Soyuz spacecraft carrying an American astronaut and two Russian cosmonauts, including the first woman cosmonaut in 17 years, blasted off on schedule Friday. Duration: 00:35 Video provided by AFP
Powered by NewsLook.com
Water Discovery On Small Planet Could Be Key To Earth 2.0

Water Discovery On Small Planet Could Be Key To Earth 2.0

Newsy (Sep. 25, 2014) — Scientists have discovered traces of water in the atmosphere of a distant, Neptune-sized planet. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

More Coverage


Pebbly Rocks Testify to Old Streambed on Mars

May 30, 2013 — Detailed analysis and review have borne out researchers' initial interpretation of pebble-containing slabs that NASA's Mars rover Curiosity investigated last year: They are part of an ... read more

Strange & Offbeat Stories

 

Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins