# Tag Info

5

You are already starting to get it. That would make sense at the poles What about one meter from the poles? Or a kilometre? As long as you can see the celestial pole in the sky, you can see the stars revolve around it at night. Let us see if you are able to see the celestial pole. Texas was about 30 degrees north last time I checked: That ...

0

The Sun would drown in the endless gravity well of the black hole, if they collide head on. The black hole would radiate nothing, unless from a disc surrounding it if more matter happens to fall into it. Sun grazing comets would make it flash a bit now and then. The sunlight would be gone, trapped beyond the horizon of spacetime. The planets would freeze air ...

3

Yes, in theory. But; No, this is very unlikely to happen during the life of the sun. If it did happen it would be Bad. Many black holes are much more massive than the sun, even though they are much smaller. If a black hole were to enter the sun, some the matter that forms the sun would form into a accretion disc around the black hole and eventually fall ...

6

The mean density of the star is really only defined by the formula $\bar\rho=M/V=3M/4\pi R^3$. The radius of a star is a generally a very complicated function of a star's other properties. When we determine the radius in stellar models, it's only because we've solved equations that describe the structure of the whole star, and read off the value at what we ...

5

Like it was already pointed out in the comments, your assertions and assumptions are way off today's well-accepted theories. Nonetheless, I'll try to answer you questions. Will our solar system die of old age in 5.4 billion years Our sun is a G-type main-sequence star with an estimated lifespan of roughly 10 billion years. Like you mentioned, it is about ...

3

This question already has muliple answers on this site... However : Yes, astronomers DO have enough data to speculate about a possible Ninth Planet. The orbits of six KBO are correlated, and a possible ninth planet could be the reason for those peculiar orbits. See image below for the computed results of the possible orbit of the ninth planet.: ...

3

Other than being kind of in the "Goldilocks" range, meaning, not too big, not too small, (not to be confused with Goldilocks-zone, that's something else), there's nothing special about our sun. There might be something a little unusual about Jupiter's movement over the last 4 billion years and perhaps, something unusual in the just right formation of our ...

0

In terms of absolute size, the sun is at the smaller end of the spectrum (the largest stars can be over 100x the mass of the Sun) but due to the skewed mass distribution in stars, the number of these massive stars is very low and the sun actually lies in the top 5% of stars by mass. The size of the sun is definitely not unique, nor are any of its properties ...

3

One thing that is, if not unique, unusual about the Sun is the size of it. It belongs to the top 5% brightest stars, meaning that 19 out of 20 stars are smaller than the Sun. Having a Jupiter size planet is certainly not unique, and plate tectonics we know nothing about for exoplanets.

3

It depends on the size of the comet. If it's only $0.1$–$1\,\mathrm{km}$, it will evaporate before even reaching the Sun (Li. et al. 2013; Knight & Walsh 2013), and the released gasses will be ejected by the Sun's radiation pressure. Larger comets, so-called Sungrazing comets, can survive close passages, although they probably will be torn apart by tidal ...

3

Well, I wasn't sure if tidal forces between Earch and Sun were strong enough to have any effect on the matter. Truth to be told, the article barrycarter linked clarifies that tidal forces have neglible meaning in comparison to the effect of Sun's nuclear fusion mass loss. That's correct. Some more details on this. Tidal "tugging" is a two ...

-4

The theorized reason I saw on the either the NASA or Discovery Channel for the Moon's orbit spiraling away from earth is that it's formation resulted from a collision between the Earth and an asteroid, and resulting momentum carries it away.

6

Yes - the earth and sun do have tidal forces like the moon and earth. There are two main reasons this is happening. The sun is always losing mass due to nuclear reactions, the sun is always converting a tiny amount of its mass into energy. This means the pull on the earth is weakened. The tidal forces that happen between us on the moon happen between the ...

4

The answer depends on the size and mass of the ball. It also depends on its ability to reflect light (albedo $A$), but let's forget that for a moment. Pressure vs. gravity Solar pressure decreases with $R^2$ (the inverse square law). At Earth, which is located at a distance of $1\,\mathrm{AU}$ from the Sun, we receive an irradiance $S_0 = ... 5 Short answer is yes. The only way radiation pressure would be a factor was if the ball was in orbit around the Sun, this would mean that the slight pressure it feels would cause it to drift away slowly (assuming its made of the most heat resistant material on Earth!). But in your question you said "placed" near the sun not in orbit around it, so the strength ... 5 This image should give you a good idea of the distances of stars relative to the Sun over the next 80,000 years (and the past 20,000 years). Image courtesy of Wikipedia user Lambiam under the Creative Commons Attribution-Share Alike 3.0 Unported license. I've created a modified version below. The nearest star's track in time is in red, and the four blue ... 1 Actually the sun's output over time does vary, and it does cause climate changes. There is an 11 year cycle as shown in this image from www.sciencemuseum.org.uk: And in the early half of the 20th century it did increase slightly, which probably did contribute to global warming during that time but over the last 50 years it has actually slightly cooled, so ... 1 The energy input of the Sun stays constant (mostly, there are some minor variations), so no, the Sun is not responsible for climate changes. The temperature of the Earth has to do with the balance between the energy input, and the energy radiated back into space. If the temperature is not changing, they are the same. Global warming is caused by gasses in ... 5 Given that Kepler has detected stars with 5 or 6 planets that exist in an extremely flattened plane and much flatter than the solar system, then we can be reasonably sure that stars with more than 4 planets are reasonably common. Given the many mechanisms for scrambling the orbital inclinations out of a perfectly flat configuration, and that seeing multiple ... 15 From an exoplanet-finding point of view, the Sun has between one and three planets. The major exoplanet-finding techniques in current use involve watching for either periodic Doppler shifts as the planet's gravitational pull causes the star to wobble, or periodic brightness shifts as the planet transits the star. Both require that the planet is large ... 5 We can't detect whether there are or are not objects of similar "small" sizes orbiting other stars. We simply lack that level of ability. From a scientific point of view I'd simply say "don't know". From a practical point of view I would expect other stars to have systems with a huge variety of things in orbit - there's no reason not to expect this, but ... 19 Between$1/40,000$and$1/8,000,000$of the brightness as seen from Earth, depending on what the actual orbit would turn out to be, and where the planet is in its$15,000$year orbit period. Brightness drops as$\dfrac{1}{r^2}$with distance from the light source. Earth is at$1~\textrm{AU}.$The theoretical planet is at$200~\textrm{AU}$when it's closest ... 9 If it exists, then the orbit has a perihelion of maybe 300 au and an aphelion of perhaps 2700 au. You can then just scale from the brightness$m=-26.7\$ of the Sun at the Earth. It would be between 12.4 and 17.1 magnitudes fainter. So still much brighter than the next brightest star in the sky.

0

Its simply mean ,when earth rotates (as Sun don't move) ,the instant when the light of sun falls on the earth called sunrise and its just opposite mean sunset.

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