Jan 21, 2021 01:42 AM
(This post was last modified: Jan 21, 2021 01:43 AM by C C.)
Trillions of noisy Brood X cicadas are set to emerge from the ground in 15 US states this spring after hiding hibernating for 17 years (seasonal weather effects)
https://www.dailymail.co.uk/sciencetech/...years.html
SUMMARY: The noisy Brood X cicada colony is set to appear this spring in 15 US states. Experts predict there will be trillions that emerge from the ground. They are expected to appear around mid-May and linger until late June. This colony has been hibernating for the past 17 years - it last appeared in 2004. (MORE - details)
Earth's Habitability Today Is Basically Due to Luck, Millions of Simulations Show
https://www.sciencealert.com/are-we-just...s-of-years
INTRO: It took evolution 3 or 4 billion years to produce Homo sapiens. If the climate had completely failed just once in that time then evolution would have come to a crashing halt and we would not be here now. So to understand how we came to exist on planet Earth, we'll need to know how Earth managed to stay fit for life for billions of years.
This is not a trivial problem. Current global warming shows us that the climate can change considerably over the course of even a few centuries. Over geological timescales, it is even easier to change climate. Calculations show that there is the potential for Earth's climate to deteriorate to temperatures below freezing or above boiling in just a few million years.
We also know that the Sun has become 30 percent more luminous since life first evolved. In theory, this should have caused the oceans to boil away by now, given that they were not generally frozen on the early Earth – this is known as the "faint young Sun paradox". Yet, somehow, this habitability puzzle was solved.
Scientists have come up with two main theories. The first is that the Earth could possess something like a thermostat – a feedback mechanism (or mechanisms) that prevents the climate ever wandering to fatal temperatures. The second is that, out of a large number of planets, perhaps some just make it through by luck, and Earth is one of those. This second scenario is made more plausible by the discoveries in recent decades of many planets outside our solar system – so-called exoplanets... (MORE)
Glaciers on Mars likely didn't form during a single ice age event
https://newatlas.com/space/nasa-mars-ice-age-glacier/
EXCERPTS: Mars may have experienced [...multiple...] ice ages ... according to the results of a new study. Glaciers that formed during the cooling periods represent fascinating targets for future exploration missions, due to the abundance of water ice, and their potential to preserve ancient material. In the present day, the Red Planet bears little resemblance to Earth, yet the Martian surface is dotted with evidence of large-scale weather processes that have shaped the alien landscape. One such process is the formation of huge glaciers.
[...] Because of their longevity, these glaciers stand as a time capsule containing a record of Mars’ geological history. However, up until now scientists had been unable to deduce whether the glaciers seen on Mars today are a result of a single massive ice age, or the accumulation of multiple cooling events.
A newly published study has shed light on this question by examining high-resolution satellite footage of multiple Martian glaciers captured by the Mars Reconnaissance Orbiter (MRO). More specifically, a research team sought to analyze the distribution of boulders that are dredged up as the glacier travels outward. [...] Their analysis didn’t reveal the gradation of boulder sizes that would be expected from glaciers formed during a single large event. Instead, the rocks found in the rivers of ice occurred in all sizes throughout the glaciers, and seemed to be clustered together in bands stretching across the ice.
The distribution of the rocks suggests that the glaciers are comprised of multiple ice flows and sediments that occurred over the course of many ice age events. Furthermore, the presence of larger boulders far downhill could be explained if the rocks are embedded within the ice rather than being carried along the surface where they could be eroded over time. According to the authors of the study, Mars has likely experienced 6 to 20 ice ages, that have contributed to the formation of the glaciers over the past 300 to 800 million years... (MORE - details)
https://www.dailymail.co.uk/sciencetech/...years.html
SUMMARY: The noisy Brood X cicada colony is set to appear this spring in 15 US states. Experts predict there will be trillions that emerge from the ground. They are expected to appear around mid-May and linger until late June. This colony has been hibernating for the past 17 years - it last appeared in 2004. (MORE - details)
Earth's Habitability Today Is Basically Due to Luck, Millions of Simulations Show
https://www.sciencealert.com/are-we-just...s-of-years
INTRO: It took evolution 3 or 4 billion years to produce Homo sapiens. If the climate had completely failed just once in that time then evolution would have come to a crashing halt and we would not be here now. So to understand how we came to exist on planet Earth, we'll need to know how Earth managed to stay fit for life for billions of years.
This is not a trivial problem. Current global warming shows us that the climate can change considerably over the course of even a few centuries. Over geological timescales, it is even easier to change climate. Calculations show that there is the potential for Earth's climate to deteriorate to temperatures below freezing or above boiling in just a few million years.
We also know that the Sun has become 30 percent more luminous since life first evolved. In theory, this should have caused the oceans to boil away by now, given that they were not generally frozen on the early Earth – this is known as the "faint young Sun paradox". Yet, somehow, this habitability puzzle was solved.
Scientists have come up with two main theories. The first is that the Earth could possess something like a thermostat – a feedback mechanism (or mechanisms) that prevents the climate ever wandering to fatal temperatures. The second is that, out of a large number of planets, perhaps some just make it through by luck, and Earth is one of those. This second scenario is made more plausible by the discoveries in recent decades of many planets outside our solar system – so-called exoplanets... (MORE)
Glaciers on Mars likely didn't form during a single ice age event
https://newatlas.com/space/nasa-mars-ice-age-glacier/
EXCERPTS: Mars may have experienced [...multiple...] ice ages ... according to the results of a new study. Glaciers that formed during the cooling periods represent fascinating targets for future exploration missions, due to the abundance of water ice, and their potential to preserve ancient material. In the present day, the Red Planet bears little resemblance to Earth, yet the Martian surface is dotted with evidence of large-scale weather processes that have shaped the alien landscape. One such process is the formation of huge glaciers.
[...] Because of their longevity, these glaciers stand as a time capsule containing a record of Mars’ geological history. However, up until now scientists had been unable to deduce whether the glaciers seen on Mars today are a result of a single massive ice age, or the accumulation of multiple cooling events.
A newly published study has shed light on this question by examining high-resolution satellite footage of multiple Martian glaciers captured by the Mars Reconnaissance Orbiter (MRO). More specifically, a research team sought to analyze the distribution of boulders that are dredged up as the glacier travels outward. [...] Their analysis didn’t reveal the gradation of boulder sizes that would be expected from glaciers formed during a single large event. Instead, the rocks found in the rivers of ice occurred in all sizes throughout the glaciers, and seemed to be clustered together in bands stretching across the ice.
The distribution of the rocks suggests that the glaciers are comprised of multiple ice flows and sediments that occurred over the course of many ice age events. Furthermore, the presence of larger boulders far downhill could be explained if the rocks are embedded within the ice rather than being carried along the surface where they could be eroded over time. According to the authors of the study, Mars has likely experienced 6 to 20 ice ages, that have contributed to the formation of the glaciers over the past 300 to 800 million years... (MORE - details)