7

Trace fossils are marks or things left behind by living things do their thing, they are indirect remains of organisms, coprolites (poop), footprints, egg shells, ect. If we found a fossilized beehive or beaver dam those would also be trace fossils. Bioturbation is a specific type of traces fossil, marks of disturbances of the sediment itself animals leave ...


6

As of 7 January 2020, the total area burnt by the fires in the whole of Australia is 8.4 million hectares (21 million acres; 84,000 square kilometres; 32,000 square miles. That is equivalent in area to the nations of Austria or the United Arab Emirates. Greater in area than the Czech Republic, Ireland or Sri Lanka. The vast majority of that has been on the ...


4

One of the next big missions to Mars, named Mars 2020 is planned to depart from Earth to Mars during late July 2020. This mission involve a very capable rover, like Curiosity on steroids. From the mission site: The mission takes the next step by not only seeking signs of habitable conditions on Mars in the ancient past, but also searching for signs of ...


3

Short answer: UT1 Long answer: The Julian Day (JD) is just a consistent day count since the beginning of the Julian period, that is January 12th 4713 BC. As the numbers tend to be large (today is day 2,458,557.5), in the 80's and motivated by computer memory limitations, the reduced JD was created which is just $JD-2400000$. Then, to remove the annoyance ...


2

Only if you factor in relativistic differences! Someone standing on the equator is traveling at about 464 m/s whereas someone standing at 41° Latitude is only traveling at about 350 m/s. Hence the person at the equator would appear to be 4.6E-06 seconds per year slower in time than the person at 41° Latitude.


2

The possible source of methane is biological, and that is what everyone is hoping for, but the more likely source is geological, produced by chemical reactions between rock and water deep underground and issuing though fissures to the surface. We are dealing with very small amounts here which are difficult to detect and measure with precision. Once out in ...


2

I make no claim to be an expert on Venus, and I welcome correction from those who are, but I think there's a misunderstanding in the question. "Venus... won't let any of the heat absorbed from the Sun out by radiation" is false. It must be, due to fairly fundamental physical laws. Now, I'm not sure whether any energy emitted from the surface of Venus ...


1

In short, weird things happen when you combine things that don't combine in nature: the Earth is a perfect sphere the Earth is spinning on an axis Einstein's equivalence principle tells us that accelerations are all the same, no matter what's causing them. So you just add the acceleration vectors up. The (real) Earth has an equatorial bulge because a ...


1

If the Earth were a perfect ball, which it is not, and had a perfectly smooth and even surface with no basins or irregularities, water would tend to move toward the equator, where it would form a bulge. Meanwhile, gravity would be pulling on this bulge and trying to drag it down, thus preventing it getting any higher and stopping the flow of water into it. ...


1

It is highly improbable that multicellular life evolved on Mars. It took billions of years for it to evolve on Earth, and it is not thought that benign conditions existed for that long on Mars. If there ever were multicellular organisms on Mars, they can only be of a microscopic sort and would have left fossils in the rocks. One of the things geologists will ...


1

Apparently, the IERS publishes values for each 0 h of UTC in their bulletins. I myself thought otherwise, but I recently noticed, in a geodesy exam, that they mentioned UTC for the daily parameters. Upon closer look at the Bulletins themselves, I was able to confirm this: Although using UT1 instead of UTC for interpolation should cause only tiny errors, ...


1

It sounds like Ingersoll was referring to Cowling's Theorem -- that flow in a planet's core that is purely symmetric around the planet's rotation axis (that would give a magnetic dipole field with no tilt) cannot produce a self-sustaining dynamo. So a magnetic field that is purely symmetric around the rotation axis, as looks to be the case for Saturn, ...


1

Oceans did form on other rocky planets - at least Venus and Mars, and moreover, many moons of Jupiter and Saturn as well. The problem is that of the two other terrestrial "uberplanets" who had oceans - i.e. the aforementioned Venus and Mars - they lost them, but in rather different ways. On Venus, what happened appears to have been that, synthesizing the ...


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