Mars is a frigid desert , but we know in the yesteryear that it hadrivers , lakes , and even perhaps an ocean . Those features are still carved in its rock today . Most of the valleys and lakes were cut up before 3.7 billion years ago , but something that is not clear is how long these water features were around . A newfangled study debate that the river flowed for only a fraction of that era .
late oeuvre calculate that it took at least tens of one thousand of year for thevalleysto word form – that ’s the minimum amount of time for those river to have flowed . But what is the maximum time ? Planetary Science Institute Research Scientist Alexander Morgan has gauge just that . He found that , at most , water was carve the rocks for 100 million years , but it was not a constant flowing .
" In this study , I used craters that predate and postdate valley systems to set maximum bounds of C of million of years on the era over which these systems form . old employment had only determined minimum timescales , so these novel results provide an upper bound on the timescale over which Martian valleys were active , " Morgan said in astatement .
" give what we recognise about corrosion rates on early Mars , long timescales entail that conditions permitting rivers were extremely intermittent , with tenacious desiccate periods intersperse with brief episode of fluvial body process . "
The cause why the activity is likely intermittent is not unmortgaged . perchance erosion was jam by boulders and terrain that were more difficult to cut up out . Or maybe , river only began to flow when the weather get warm enough , or after some particularly potent volcanic activeness . The climate of a satellite can change , like the changes responsible for Earth ’s periodicglacial periods .
The oeuvre add some nuance to thepast history of Mars . Was the Red Planet " strong and wet " with an ocean ? Or was Mars " frigid and gelid " with massive ice sheets ? It could have had its periods ofwarmthover longer frigid and dry epochs .
" Over the past X or so we ’ve come to actualize that these descriptor are far too cosmopolitan , and it does n’t really make mother wit to seek to contract 100 of millions of years of climate history into a two - parole verbal description , " Morgan said .
" Like Earth , other Mars was complex , and the conditions allow surface pee likely varied considerably . Earth has undergone massive climatic changes throughout its history – for example , 20,000 days ago , the area that is now Chicago was beneath half a mile of ice – and airfoil condition permitting rivers on former Mars likewise plausibly rise and wane . "
The study is published inEarth and Planetary Science Letters .
