# Tag Info

10

If you are asking about short-term effects related to human's effect on the climate, the answer is (obviously) unclear. But in the very long term, Earth is likely to evolve to a more Venus-like state. Over the next billion years or so, the Sun's luminosity will slowly increase, which will heat Earth's surface. As a result, more water vapor will evaporate ...

10

Either or neither. It's impossible to tell from the present. If runaway climate change occurs, then yes, the conditions on Venus could be a potential analogue for the kind of environment on Earth due to the greenhouse effect. Mars's atmosphere is assumed to have been much thicker in the past, otherwise it could not have sustained liquid water on the ...

7

It'll have basically no effect on the planet's orbits, except perhaps on the theoretical planet 9 and even then, not very much. As close as it's expected to get Gilese will till be too far away to affect the 8 planets much. Gilese 710's mass is about 60% the mass of our Sun. I've seen two estimates, of 13,000 Astronomical Units (AU) and 13,365 or about 77 ...

6

That is nearly long enough to reach heat-death, which is estimated as about $10^{10^{120}}$. What that means is rather speculative, since it depends on various events that we have never observed, such as the spontaneous formation of black holes by quantum tunnelling. Such events are utterly rare, but are predicted to occur at very long timescales. Any ...

6

This is a question that cannot be accurately answered. However, the closest to a honest and accurate answer would be that neither, since the Earth is going to "evolve" (curious choice of words) towards the Earth's fate. The presence of humans means any purely physical projections need to be taken with a grain of salt. Our ability to influence the planet ...

6

The book is incorrect. The calendar is designed to keep track of the seasons. What will happen in 13000 years is that the Northern Hemisphere summer solstice will still occur near the end of June, but it will occur near perihelion rather than near aphelion. In 13000 years, summers in the Northern Hemisphere will be short but intense, and winters will be both ...

5

Astronomer is moving towards the big(ger) data era because of many sky survey technologies. The coming ones include, e.g., LSST, JWST, and WFIRST. By the meaning of survey, it normally means observing the whole sky over a few days, and keep repeating over and over. Also, since most of the surveys are imaging technologies, every pixel in an image is ...

5

Asteroids come in all shapes and sizes, and generally the bigger they are the easier they are to detect. Small asteroids, from a the size of sand grains (properly called meteoroids) to a few meters across hit the Earth everyday without causing harm and are undetectable until they hit (we call the trace as they hit the atmosphere a meteor) They cause no ...

5

How can we use hypervelocity stars to determine the origins of the Universe? First and foremost, I should clear something up: our knowledge of the Big Bang is incredibly limited, and so we don't even know the origins of the Universe today. General relativity and quantum mechanics both break down as you get closer and closer to $t_0=0$. All we really know is ...

4

These stars are currently moving away from us, in the case of Epsilon Eridani, at 15.5 km/s. In 31500 years they will be further away than they are now, the distance can be calculated by applying Pythagoras' theorem to the distances and velocities you mention. It turns out that Eps Eri will be about 12.2 light years from Earth, and Lutyen 726-8 will be 12.6 ...

3

Since the Sun's temperature will continue to increase and it is estimated that in ~2 billion years it will be so hot on Earth that life will be impossible, I'd say it's going to evolve more toward Venus.

3

I'm an astronomer and I get lots of job offers to retrain as a data scientist, but it might be more tricky to go the other way. Astronomy is definitely a field in which 'big data' is important, and the analysis and visualisation techniques we use every day are probably decades behind what is taught to computer scientists. However, most astronomy software is ...

3

Sometime before now and "tens of millions of years". Phobos currently orbits at a radius of about 9400km The theoretical Roche limit is different for rigid and fluid bodies. If Phobos were a fluid body, it would already have passed the Roche limit at 10500km. This is because fluid bodies will deform into an ellipse pointing towards the planet, ...

2

The diagram from Astronomy magazine is correct; the book excerpt is a little confused. Winter solstice is not when the Sun appears opposite certain stars, but when the Sun appears farthest from the Earth's north pole. The time-dependent difference between these is due to axial precession. There are several different definitions of a year: Name Mean Length ...

2

Here is a render of what an observer might see near the edge of our galaxy. The "edge" itself being rather fuzzy, let's assume that we are in an area of the edge dense enough where a few occasional stars are still visible. (As far as we know, intergalactic space contains objects and stars, but so few that seeing even one naked-eye star in the sky there would ...

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