What is the first star to shine at night?

Answer 1

All stars use what is called nuclear fusion to create energy in the form of heat and electromagnetic radiation. But every reaction, including nuclear fusion, requires a certain amount of excess energy called "activation energy" to start reacting. for nuclear fusion this activation energy is in the billions of Killijoules, but luckily it's easier than that. first of all a ball of dense gas absorbs enough energy to react on a smaller scale. this allows the built up bonds in the gas to break down and release excess energy and create new products (commonly known as combustion) the energy released through combustion eventually becomes enough to start the process of nuclear fusion and the star is born.

Answer 2

When its outer parts get hot enough - a few hundred degrees. This will happen before it actually starts fusing hydrogen; just by contracting it will start getting hot, and start to glow. In other words, when it is in the protostar phase.

Answer 3

No.

Although, in the Northern Hemisphere, Polaris (the North Star) has the advantage of always being above the horizon, and therefore potentially visible, it is by no means the brightest star in the sky, and therefore will not be visible before brighter stars are.

So, taking your phrase "first star to shine at night" to mean the first star visible to the naked eye as darkness falls, that will usually be the brightest star in the sky at that time of the year (with an advantage to the star higher in the sky).

The six brightest stars readily visible in the Northern Hemisphere are Sirius, Arcturus, Vega, Capella, Antares, and Rigel. Depending on their height above the horizon, other prominent stars such as Altair, Antares, Acrux, and Deneb may be the first seen.

Of course, the bright planets Venus, Mars, Jupiter, and Saturn are often the first star-like objects seen because they can be very bright, but they are not stars.

Answer 4

The first stars were formed at the start of the Universe, some 13 billion years ago.

After the Big Bang, the universe was mostly 'smooth', with just small ripples in the matter density. These ripples grew larger due to the gravitational forces acting on the dark matter particles contained in them. Eventually, gas was pulled into the forming structures, leading to the formation of the very first stars, about 100 million years after the Big Bang.

Answer 5

No, far from it. In fact, Polaris is the dimmest of all the stars commonly used in celestial navigation. Except for the fortunate coincidence that Polaris happens to be almost precisely above the north pole, nobody would look twice at it.

Depending on the season and the date, the "first star I see tonight" is usually either the planet Venus, the planet Jupiter or the stars Vega or Sirius.

Answer 6

Because it has reached the temperature critical for fusion to begin; when the pressure in the center causes the core to reach a temperature of ~10,000,000 K (~18,000,000 F), hydrogen fusion is initiated. If Jupiter were about 8 times more massive, it would have "critical mass" and we would see two bright stars in our sky!

Answer 7

The brightest star you can see in the Southern Hemisphere is Sirius, which is the brightest one of all from earth (excluding our sun). It has to be the right time of year though as it can also enter northern skies. Your chances of seeing it higher in the sky are better as you get nearer the equator.

Sometimes people mistake the first bright star in the sky with a planet such as Venus, mars, Saturn or Jupiter, which all can be quite bright at times, particulary Venus.

Answer 8

As a gas cloud collapses under its own gravity, the pressure and temperature both increase. When the temperature and pressure becomes high enough, the "gas cloud" becomes a star, when nuclear fusion of the hydrogen begins.

Answer 9

When gravity (compression) heats up the gasses (that make up its body) sufficiently.

Answer 10

The star dies. As for the effect when it dies, it depends on the size of the star. A star that is 100 times larger than the sun will collapse and cause a violent explosion called a supernova