Sentences with phrase «on early earth»

1979 Tobias Owen, et al., «Enhanced CO2 Greenhouse to Compensate for Reduced Solar Luminosity on Early Earth.»

Solar luminosity on the early Earth was significantly lower than today.

A lot of stuff written on the early earth seems conflicting and outdated, it's hard to know what's the real deal.

Think of all the work on the Neoproterozoic Snowball Earth, the evolution of oxygenic photosynthesis on the Early Earth and its role in the transition from a methane - dominated to a CO2 - dominated greenhouse, Martian paleoclimate, the climate of Venus and Titan, the nature of the glacial - interglacial cycles, and so many more.

Astrobiology Goal 4: Life on Early Earth Astrobiology Goal 5: Environmental Limits of Life A Question of Climate Tiny Pieces of Time Clues from Vesta Earth's Early Temperature Early Earth with Crust Please

* Guillaume Gronoff from NASA's Langley Research Center in Hampton, Virginia, will discuss how energetic particle events from the young Sun impacted the chemistry of the early Earth's atmosphere and ignited conditions for prebiotic chemistry on early Earth and Mars.

* Professor Nicholas Hud from Georgia Institute of Technology, Ramanarayanan Krishnamurthy and Jeffrey Bada from Scripps Research Institute, Robert Pascal from University of Montpellier, France, and Kensei Kobayashi from Yokohama National University, Japan will discuss environmental requirements for the rise of prebiotic chemistry on the early Earth.

Now, scientists at Rensselaer are turning these atmospheric assumptions on their heads with findings that prove the conditions on early Earth were simply not conducive to the formation of this type of atmosphere, but rather to an atmosphere dominated by the more oxygen - rich compounds found within our current atmosphere — including water, carbon dioxide, and sulfur dioxide.

Just two years ago a group had studied the likely timing of impacts on the early Earth and they suggested that these impacts might explain the ages of the ancient zircons.»

Microbial life on early Earth evolved and changed the environment, thereby enabling the evolution of more complex life.

Regardless of when the cyanobacteria appeared, it is widely accepted that they comprised the predominant form of life on early earth for some two billion years, and were responsible for the creation of earth's atmospheric oxygen, consuming CO2 and releasing O2 by photosynthetic metabolism.

«This discovery further demonstrates how important interstellar chemistry may be to understanding the creation of biological molecules on the early Earth,» said Jewell.

Complex molecules in space are of interest for many reasons, including their possible connection to the formation of biologically significant molecules on the early Earth.

If microbes once survived in these pockets on early Earth, they could potentially have done so on other planets too, Airo says.

However, current evidence suggests that plate tectonics — as we know it today — was not occurring on the early Earth.

Alternatively, some hypothesize that the reservoir of light carbon on the early Earth indicates the presence of simple organic compounds — possibly brought by asteroidal or cometary impactors — that created a hospitable environment for the later emergence of life (more discussion in Rachel Courtland, New Scientist, July 2, 2008; Sid Perkins, Science News, July 2, 2008; and Jonathan Fildes, BBC News, July 2, 2008).

The presence of sulfur and sulfuric acid, however, may have also been present on the early Earth and is compatible with many extreme environments where bacteria have evolved biochemical processes to extract energy without sunlight (e.g., to extract energy from the charged reactions of sulfuric acid).

As impact glass is a ubiquitous substrate on rocky bodies throughout the Solar System and likely common on the early Earth, the preservation of biological activity in impact glass has significant astrobiological implications for life on early Earth as well as for the search for life on other planets.

Ever since Stanley Miller inaugurated the era of serious research in the origin of life, chemists have been at the forefront of answering the question at the crux of the matter: how did the simple, primordial molecules on an early Earth self - assemble to form self - replicating, robust chemical structures subject to Darwinian natural selection?

The fact is that even if we don't know which single pathway operated on the early earth — and since evolution proceeds in multiple directions the question may even be pointless — we can get very close to narrowing down well - defined possibilities in the near future.

«I love what Steve is doing,» he says, though he's still not convinced the early Earth could not have supported Benner's chemical pathway — he reckons there might have been dry patches on early Earth where the chemistry Benner proposes could have occurred.

«This could be a tiny place where we still have a remnant of the kinds of prebiotic conditions that might have existed on early Earth.»

But where the first RNA came from is a mystery; it's hard to see how the chemicals on early Earth could have combined to form the complicated nucleotides that make up RNA.

Future work will look at what else could have limited the growth of life on the early Earth.

The Miller - Urey experiment, conducted in 1952 to simulate conditions believed to have existed on the early Earth, produced more than 20 different amino acids, organic compounds that are the building blocks for peptides.

«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.»

Magnesium - rich minerals in the magma might power the most intense eruptions, an exotic process that raged on the early Earth but ceased long ago.

Knowing what conditions were like on the early Earth therefore gives scientists a stronger foundation for hypothesizing what could have taken place, and could offer hints to other pathways that may not have been considered yet.

«We now have a really good way to synthesize peptides with amino acids and hydroxy acids working together that could have been common on the early Earth,» he said.

An analysis of a fossilised rain shower suggests air density on early Earth was broadly similar to today's — making it difficult to explain why Earth was warmer than it is now when the sun shone less brightly.

«Lagoons or, in more general terms, shallow - water protected settings, are likely to have been well developed on the early Earth,» says Lowe.

In an oxygen - free atmosphere, as prevailed on early Earth, uranium stayed immobile in rocks as tetravalent uranium (IV).

They simulated a meteorite impact on early Earth by firing a high - power laser at samples of formamide — a liquid that would have existed on our primordial planet.

Donald Lowe, a geologist at Stanford University who studies the Late Heavy Bombardment, says such environments did exist on early Earth — despite the disruption caused by the impacts.

Now, researchers working with that hypothesis have achieved a significant advancement toward understanding an evolutionary mystery — how components of RNA and DNA formed from chemicals present on early Earth before life existed.

Rocks in Greenland that have been preserved for 3.7 billion years show evidence of microbes living in a shallow sea on early Earth

It's «nice chemistry,» says marine chemist Jeffrey Bada of the University of California (UC), San Diego, but he is not convinced that hydrothermal vents, or any other likely habitat on early Earth, could have provided the conditions created in the lab: «The processes outlined are not likely to take place on a significant scale on the Earth or elsewhere.»

Under the conditions you might find on early Earth, the phosphorylated sugar groups which make up RNA's backbone are unstable and don't easily...

It is perfectly possible that sponges came before, and helped bring about, fully oxygenated oceans, says Timothy Lyons at the University of California, Riverside, who studies the variation in oxygen levels on early Earth.

A physical environment that could plausibly have existed on the early Earth «actually selects for longer RNA sequences,» she says.

And a separate experiment, published in Nature in May, showed that it is possible for the building blocks of RNA to emerge spontaneously from simple molecules thought to have been present on the early earth.

«We now have a pathway that would allow us to use simple molecules that were likely present on the early Earth,» says Carell.

«A lot of the chemistry on early Earth involved the same chemicals, but Titan has them in a deep freeze,» Stofan says.

The moon is one of a number of «ocean worlds» in our solar system that hold the ingredients for life, and is known to be covered with rich organic material that is undergoing chemical processes that might be similar to those on early Earth, before life developed.

«The reactions we observed in our experiments have shown that the necessary prebiotic molecules were likely present on the early Earth and that the Earth was predisposed to phosphorylated biomolecules,» the researchers concluded.

Their goal was to synthesize amino acids — the building blocks of life — as they might have been created on early Earth.

The easiest way to explain that, Saal says, is that the water was already present on the early Earth and was transferred to the Moon.

It envisions the great reshuffling as a brief, violent affair that not only put the outer planets where they are today but also created the Kuiper belt of small icy bodies beyond Neptune, gave the planets scores of oddly orbiting moons, and bombarded the solar system with a rain of asteroids and comets so fierce that it would have cooked all but the deepest subterranean life on early Earth.

SwRI scientists created a new model for impact - generated outgassing on the early Earth.

More information on the metabolism of this organism can therefore shed new light on the long - standing discussion of the role of iron metabolism on early earth.