Why are we able to see the stars at night?

Question

How thick is the Earth's atmosphere? You would think that with the thickness of the atmosphere (so that it can protect us) you wouldn't be able to see the stars at night.

Answer 1

Most of the atmosphere is made up of gases which are transparent and do not hinder vision. That is why you are able to see stars even through the atmosphere which is hundreds of kilometers thick.

Answer 2

The atmosphere is about 100 km thick, but the gases that make up the atmosphere are colorless. And at night there is not alot of light so you can see the stars.

Answer 3

What? Why would you think that?

We can't see them during the day because the light of the sun obscures them. If you put a candle at one end of a big hall lit with flurescent lights, you won't see it's glow. Likewise, during the day we can't see the stars. When there is no sunlight, the light from the stars becomes visible.

It has nothing to do with the earths atmosphere, which at any rate is made up of clear, colourles gases which allow light to pass through unimpeded.

Answer 4

The reson we see the stars is becuase sun llight is not there In pesenece of a light a smaller light wiill not be visible)In bedroom if a 100 watt light is on see a zero watt light and then switch off the 100 watt light to see the impact). I do not think atmosphere has anyting to do as it is transparent

Answer 5

Earth's atmosphere is fairly transparent at visible wavelengths. Straight overhead, starlight is only dimmed by about 0.2 magnitudes (17%), though it is only a third as bright 10° above the horizon.

Answer 6

yes,we can see the stars at night this is because particular atmosphere present in that stars like the carbon dioxide filled the entire area.for example take our Venus itself it is much brighter this is because more no. of carbon dioxide filled in that atmosphere,this generates some sort of heat & hence its shines.

Answer 7

Because that's when there out there---Really, they are looking at us at night because they are not working and they have more time.

Answer 8

We can see stars because they are shine!

Answer 9

A star is a massive, compact body of plasma in outer space that is currently producing or has produced energy through nuclear fusion. The most familiar and closest star to the Earth is the Sun. Unlike a planet, from which most light is reflected, a star emits light because of its intense heat. Stellar astronomy is the study of stars.

Individual stars differ from each other due to their total mass, their composition, and their age. The total mass determines the course of evolution of a star, as well as its eventual fate. A Hertzsprung-Russell diagram shows the pattern of the temperature of stars against their absolute magnitude, and can be used to determine the overall age of a star and the stage in its evolution. Initially, stars are composed primarily of hydrogen, with some helium and heavier trace elements that determine the metallicity of a star. Over the course of a star's evolution, a portion of the hydrogen is converted into heavier elements through the process of nuclear fusion. Part of the matter is then recycled back into the interstellar environment, where it is used to form a new generation of more metal-rich stars.

Multi-star systems consist of two or more stars that are gravitationally bound, and generally move around each other in stable orbits. When two such stars have a relatively close orbit, their gravitational interaction can have a significant impact on their evolution. For example, a nova occurs when a white dwarf accretes matter from a companion star
Star formation occurs in molecular clouds, large regions of high density in the interstellar medium (though still less dense than the inside of an earthly vacuum chamber). Star formation begins with gravitational instability inside those clouds, often triggered by shockwaves from supernovae or the collision of two galaxies (as in a starburst galaxy). High-mass stars powerfully illuminate the clouds from which they formed. One example of such a star-forming nebula is the Orion Nebula.[1]

A protostar forms at the core of a collapsing cloud of gas and dust. These pre-main sequence stars are often surrounded by a protoplanetary disk, and their energy is powered through gravitational contraction. Early stars of less than 2 solar masses are called T Tauri stars, while those with greater mass are Herbig Ae/Be stars. The period of gravitational contraction lasts for about 10-15 million years. These newly-born stars emit jets of gas along their axis of rotation, producing small patches of nebulosity known as Herbig-Haro objects.[2]

Stars spend about 90% of their lifetime fusing hydrogen to produce helium in high-temperature and high-pressure reactions near the core. Such stars are said to be on the main sequence. Starting at zero age main sequence, the amount of helium in a star's core will steadily accumulate. As a consequence, in order to maintain the required rate of nuclear fusion at the core, the star will slowly increase in temperature and luminosity.[3] The Sun, for example, is estimated to have increased in luminosity by about 40% since it reached the main sequence 4.6 Gyr ago.[4]

Small stars (called red dwarfs) burn their fuel very slowly and last tens to hundreds of billions of years. At the end of their lives, they simply become dimmer and dimmer, fading into black dwarfs.[citation needed] However, since the lifespan of such stars is greater than the current age of the universe (13.7 billion years), no black dwarfs exist yet.

As most stars exhaust their supply of hydrogen, their outer layers expand and cool to form a red giant. In about 5 billion years, when the Sun is a red giant, it will be so large that it will consume both Mercury and Venus. Eventually the core is compressed enough to start helium fusion, and the star heats up and contracts. In low mass stars (less than the 1.4 solar mass) the helium fusion process begins with an explosive burst of energy generation known as a helium flash. The energy resulting from this event is equivalent to the luminosity of 108 Suns, but it only lasts upto a few minutes. However, this energy goes into the elimination of the electron degeneracy at the core, and is not visible from the exterior.[5]

Larger stars will also fuse heavier elements, all the way to iron, which is the end point of the process. Since iron nuclei are more tightly bound than any heavier nuclei, if they are fused they do not release energy — the process would on the contrary consume energy. Likewise, since they are more tightly bound than all lighter nuclei, energy cannot be released by fission. In old, very massive stars, a large core of inert iron will accumulate in the center of the star.

An average-size star (less than 1.4 solar masses after explosion) will then shed its outer layers as a planetary nebula. The core that remains will be a tiny ball of electron degenerate matter not massive enough for further compression to take place, supported only by degeneracy pressure, called a white dwarf.[6] These too will fade into brown, and then black dwarfs over a very long stretch of time. Electron degenerate matter is not plasma, even though stars are generally referred to as being spheres of plasma.


The Crab Nebula, remnants of a supernova which occurred around 1050 AD.In larger stars, defined as having more than 1.4 solar masses after explosion, fusion continues until an iron core accumulates that is too large to be supported by electron degeneracy pressure. This core will suddenly collapse as its electrons are driven into its protons, forming neutrons and neutrinos in a burst of inverse beta decay. The shockwave formed by this sudden collapse causes the rest of the star to explode in a supernova. Supernovae are so bright that they may briefly outshine the star's entire home galaxy. When they occur within the Milky Way, supernovae have historically been observed by naked-eye observers as "new stars" where none existed before.[7]

Eventually, most of the matter in a star is blown away by the supernovae explosion (forming nebulae such as the Crab Nebula[7]) and what remains will be a neutron star (sometimes a pulsar or X-ray burster) or, in the case of the largest stars (more than 3 solar masses after explosion), a black hole.[8] In neutron stars and black holes, the star is not in a plasma state of matter, but either neutron degenerate matter or a state of matter not currently understood within the black hole.

The blown-off outer layers of dying stars include heavy elements which may be recycled during new star formation. These heavy elements allow the formation of rocky planets. The outflow from supernovae and the stellar wind of large stars play an important part in shaping the interstellar medium.