# Tag Info

## New answers tagged sun

2

The Sun has lots of features "like the red spot", but they are dissimilar too. Similarities: The Sun's photosphere - the bit we can see - is entirely gaseous; the photosphere rotates differentially with solar latitude; the gas is turbulent. There are features that can be seen quite easily - these are the dark magnetic sunspots, typically of size a few ...

-1

I'm not an astronomer, just an enthusiast, but I believe the only way that the sun could become a black hole is if when the Andromeda galaxy and the Milky Way galaxy collide, if our star combines with another star and the mass of the two is great enough to create a black hole then it's possible; however, from what I've read, despite the enormous size of ...

-1

No. Our star is to SMALL to become a black hole.

0

I want to expand on the use of an AU in comparing planetary systems a bit. When we look for example at this image of the (instantly famous) protoplanetary disc imaged last year in HL Tau: In observational astronomy, when we look at an object at a distance $d$ and it has a certain angular size $a$, thanx to the use of the century old parsec we know the ...

0

I guess the use of one unit over the other (AUs, parsecs,lightyears, etc.) will depend mainly on the distances of the object under study. If you work with Solar System objects, it will be easier to use AUs, whereas if you work with Galaxies, AUs are not much use and you'd probably work better with lightyears.

8

Certainly. Astronomical Unit is probably one of the most used distance units used in astronomy. It is of course only used when discussing the distances within a stellar system, such as the distances between the Sun and its planets or other bodies in the solar system. It is also used to discuss distances in other stellar systems, e.g. the distances between ...

6

Fire is actually the rapid oxidation of a combustible material. Smoke is the airborne particulates and gases that result from the combustion, or from pyrolysis. The sun is not undergoing an oxidation reaction, so it's not producing particulates that one might refer to as smoke. The process the sun is undergoing is nuclear fusion, where hydrogen are ...

27

The sun isn't on fire. Fire is actually very rare in the solar system. It requires chemical potential energy, which happens on earth because of life. Photosynthesis uses solar energy to build things out of carbon, oxygen, nitrogen and hydrogen (and some other elements). It's these carbon chain structures that are ultimately flammable, and pretty much, ...

6

The sun is not actually on fire, like a log burning. In the core of the sun, a nuclear reaction takes place that generates heat. Because the sun is so large, it generates a lot of heat and it glows like an incandescent light bulb.

0

The speed of light in a vacuum is 299,792,458 meters per second, not infinite. Let's say, for example, particle of a beam of light, the photon, is emitted. It takes ~8 minutes to get to us; when it hits our eyes, we see it. This means that we see a photon that was emitted from the sun 8 minutes ago. We aren't, per se, looking "back in time", but we're ...

0

The Sun has a very powerful magnetic field. But the rotation of the Sun on its axis is uneven. The velocity of rotation is higher at the equator and lower at the poles. Due to the large difference in the velocities, the magnetic field lines gets twisted and turned that causes some of them to come really close. The instability causes an outburst seen as solar ...

0

The orbit of the Sun around the Galaxy is quite complicated, because unlike the solar system, the mass is not completely concentrated at the centre. So, in addition to the roughly circular 230 million year orbit in the plane of the Galaxy, there are superimposed motions in and out of the plane and towards and away from the Galactic centre. These roughly ...

1

Magnetic fields are generated by currents - i.e. by the motion of charged particles. As you say, the Sun is full of freely moving charged particles, and these generate currents which in turn generate magnetic fields. No metals required. Most of the magnetic field generation is thought to occur at the interface between the radiative interior of the Sun and ...

3

The Big Bang theory predicts that (depending what assumptions you choose) the initial elements were formed from 10 seconds to 20 minutes after the Big Bang. The initial elements were mostly hydrogen some deuterium some helium-3 and helium-4 a little lithium-7 a couple of unstable isotopes that decayed to lithium-7 or helium-3. As the linked Wikipedia ...

3

The first part of your question has been asked before: Is Sun a part of a binary system? and the current (lack of) evidence for such a companion is discussed on the relevant wikipedia page about "Nemesis". To summarise: if it were a small companion star, or even a brown dwarf that had been cooling for 4.5 billion years and it had a 26 million year orbit, ...

-1

Revised: There are several reasons why the sun cannot be part of a binary system (even if the orbit is 26 million years). If the star has the mass of Sol, the binary system would orbit around the point equal distant from both masses. This would definitely show a change in parallax for some of the stars. A Sol size star in a 26 million year orbit (about ...

0

The evidence is not only in Earth's climate but Earth's magnetic field too. For more evidence you can search for yourself too. Of cource there is the complete physical mechanism described, not just correlations. And the mathematical documentation is overwhelming. Pela: there is no such thing as self-tidal force, the only tidal forces to the Sun are those ...

6

You don't have to guesstimate to come up with the answer. What you do is look at the dynamics of stars with respect to the Galactic plane - in particular, the velocity dispersions of stars with known distances from the plane, combined with a reasonable assessment of where the Sun is with respect to the plane (close), yields an almost model-independent ...

0

May I try to contribute to that conversation? Indeed the forces from planets are very weak BUT what is the sun? Gas collapsing because of gravity on one hand and on the other hand expanding due to nuclear reactions. All this in an equilibrium. So this small planetary power seems to affect the sun, in the absence of other stronger powers. An analogy is that ...

2

Very roughly: $3.5 \times 10^{33}kg$, or 1800 solar masses. Here's how I came by that number, it is a very rough approximation. The major mass components of the galaxy are stars, the interstellar medium, and dark matter. According to the HYG Database there are approximately 1000 stars within 50 light years of the Earth. The average mass of a star is ...

0

The Sun does NOT revolve around an even bigger star. If it did, you'd see two stars, assuming the larger one didn't outshine the Sun. In that case, you'd only see one. Also, the earth would be a lot hotter, getting heat from two stars. We'd also be in danger of solar wind, more solar wind than we'd usually get from just the Sun. So, because we don't see two ...

Top 50 recent answers are included