More than 3 billion years ago, Earth was a hostile, volatile place, its air oxygen-less and its climate unpredictable.

And yet, life thrived.

That’s according to a study published Monday in the journal Nature, which analyzed 52 ancient rock samples and found that organisms capable of pulling nitrogen from the atmosphere and converting it into a usable form first appeared around 3.2 billion years ago — about a billion years earlier than previous estimates.

Though very early, very basic forms of life are thought to have existed even earlier than the 3.2 billion mark, the new findings push back scientists’ understanding of when life was widespread.

The secret ingredient is a type of nitrogen found in the ancient rock samples. Early life forms may have been able to live without oxygen — which didn’t appear in Earth’s atmosphere until what scientists call a “great oxygenation event” 2.3 billion years ago — but they required nitrogen to build genes and for other essential life processes. And unfortunately for the planet’s ancient organisms, the kind of nitrogen in Earth’s atmosphere exists in tightly bonded pairs that are useless when it comes to chemical reactions.

Non-biological processes, such as lightning discharge, may have converted bonded atmospheric nitrogen in small quantities, but not frequently enough to sustain large populations of living cells. For that, life on Earth needed to find a way to acquire its own nitrogen — an enzyme that could pull the compound from the atmosphere and convert it to its “fixed” or usable form.

Evidence of such an enzyme is what researchers found in their samples, which were sourced from some of Earth’s oldest rock in South Africa and Australia and range from about 2.8 billion to 3.2 billion years old. The rocks contain a chemical signature of the nitrogen-fixing process, offering “hard evidence” that the conditions for life to flourish have existed 50 percent longer than scientists once believed, according to co-author Roger Buick.

“People always had the idea that the really ancient biosphere was just tenuously clinging on to this inhospitable planet, and it wasn’t until the emergence of nitrogen fixation that suddenly the biosphere become large and robust and diverse,” Buick, a professor at the University of Washington, said in a university press release. “Our work shows that there was no nitrogen crisis on the early Earth, and therefore it could have supported a fairly large and diverse biosphere.”

Source: Kanfustudio

Buick said these early organisms could have crawled out of the ocean and lived on land in a single layer of cells, coating the planet’s rocks with a thin film of slime and quietly exhaling small amounts of oxygen. The presence of the chemical signature is indirect evidence of this hypothesis, but it’s firm — the kind of chemical reaction preserved in the rocks can only happen in the presence of life.

Lead author Eva Stueken, also a University of Washington professor,said that the findings suggest it may be easier for complex biological processes to develop than originally thought.

“Imagining that this really complicated process is so old, and has operated in the same way for 3.2 billion years, I think is fascinating,” she said. “It suggests that these really complicated enzymes apparently formed really early, so maybe it’s not so difficult for these enzymes to evolve.”

Source: Washingtonpost

There is nothing better than a bit of mythbusting (which accounts for the popularity of the television program of the same name), so here we are again, presenting you with a new list of terribly common misconceptions and myths – this time about science.

5- Evolutionary Improvements

The Myth: Evolution causes something to go from “lower” to “higher”

While it is a fact that natural selection weeds out unhealthy genes from the gene pool, there are many cases where an imperfect organism has survived. Some examples of this are fungi, sharks, crayfish, and mosses – these have all remained essentially the same over a great period of time. These organisms are all sufficiently adapted to their environment to survive without improvement.

Other taxa have changed a lot, but not necessarily for the better. Some creatures have had their environments changed and their adaptations may not be as well suited to their new situation. Fitness is linked to their environment, not to progress.

4- Humans Pop In Space

The Myth: When exposed to the vacuum of space, the human body pops

This myth is the result of science fiction movies which use it to add excitement or drama to the plot. In fact, a human can survive for 15 – 30 seconds in outer space as long as they breathe out before the exposure (this prevents the lungs from bursting and sending air into the bloodstream). After 15 or so seconds, the lack of oxygen causes unconsciousness which eventually leads to death by asphyxiation.

3- Brightest Star

The Myth: Polaris is the brightest star in the northern hemisphere night sky

Sirius is actually brighter with a magnitude of ?1.47 compared to Polaris’ 1.97 (the lower the number the brighter the star). The importance of Polaris is that its position in the sky marks North – and for that reason it is also called the “North Star”. Polaris is the brightest star in the constellation Ursa Minor and, interestingly, is only the current North Star as pole stars change over time because stars exhibit a slow continuous drift with respect to the Earth’s axis.

2- Five Second Rule

The Myth: Food that drops on the floor is safe to eat if you pick it up within five seconds

This is utter bunkum which should be obvious to most readers. If there are germs on the floor and the food lands on them, they will immediately stick to the food. Having said that, eating germs and dirt is not always a bad thing as it helps us to develop a robust immune system. I prefer to have a “how-tasty-is-it” rule: if it is something really tasty, it can sit there for ten minutes for all I care – I will still eat it.

1- Dark side of the Moon

The Myth: There is a dark side of the moon

Actually – every part of the moon is illuminated at sometime by the sun. This misconception has come about because there is a side of the moon which is never visible to the earth. This is due to tidal locking; this is due to the fact that Earth’s gravitational pull on the moon is so immense that it can only show one face to us. Wikipedia puts it rather smartly thus: “Tidal locking occurs when the gravitational gradient makes one side of an astronomical body always face another; for example, one side of the Earth’s Moon always faces the Earth. A tidally locked body takes just as long to rotate around its own axis as it does to revolve around its partner. This synchronous rotation causes one hemisphere constantly to face the partner body.”

Source: Listverse