Why do we use parallax?

Answer 1

As Earth orbits the Sun individual stars seem to move their position against the celestial background. The nearer a star is to is, the greatest that apparent move is. That apparent change in the stars position is known as its parallax. A star close enough to show a change of 1 second of an arc is said to be at a distance of one parsec. No star is actually that close. Proxima Centauri, the nearest start to us after the Sun, is 0.75 of a second of an arc. One parsec is equivalent to 3.76 light years. The farther away a star is, the smaller its parallax. Stars over 50 light years away have a parallax that is too small to measure, even with the most powerful of telescopes. Only about 1000 stars have an accurately measured parallax. Beyond that, the absolute magnitude of a star is used to estimate its distance, which relates to its brightness.

Answer 2

We use parallax to measure distances to nearby stars by observing how their positions shift relative to more distant stars as the Earth moves in its orbit. This technique is important in astronomy because it allows us to determine the scale of the universe and understand the true distances between celestial objects.

Answer 3

a paralax can be used to measure the relation of the distance between one star to another.such as, when you take a picture of a star, and another of that same star six months later, with the paralax you can see how far they moved.

Answer 4

Well it's pretty simple, you know what a parallax is, as you experience it all the time. Like your in the car, and your moving... you can see the stationary objects closer to you seem to be moving faster than the objects further away. The apparent change in position is the parallax, and it is measured in the terms of "The angle of parallax", the greater the angle, the closer the object is.

So in terms of nearby stars, it is used to measure the distance, by calculating and observing how they move relative to very distant stars, when the earth is in different parts of it's orbit. And this distance unit is called a parsec.

Umm... it's measured per say when earth is in January and in July during it's obit, and is observed to see how it has moved... so the distance from earth to that star, along with knowing that earth is exactly 1 astronomical unit away from the sun, creates a right angled triangle per say. And using that triangle and trigonometry, we can measure the angle of the paralax, to work out the stars distance.

Hope this helps!

Answer 5

The estimates of the number of stars in the Milky Way stars at about 4 billion, and goes up rapidly from there. I suspect that there are far more stars than we are aware of, because I don't think that anyone has given serious thought to the number of tiny, barely-fusing brown dwarf and red dwarf stars.

For example, the NEAREST star to our Sun is Proxima Centauri. But Proxima isn't visible to the naked eye, you need a good telescope to see it AT ALL. It's only 4.2 light years away, our closest neighbor - and yet invisibly dim!

How many similar stars at distances of thousands or tens of thousands of light years away might there be? All invisible!

Answer 6

Scientists calculate the distance to galaxies using 'redshift'. in brief, the farther a galaxy is, the greater the difference in speed between it and our galaxy, and large differences in speed mean that the wavelengths of light from that galaxy become longer. this shifts light spectra downwards (visible light shifts towards the red end of the visual light spectrum, hence redshift). the amount that a known spectrum (say the spectrum of hydrogen atoms) of material in a galaxy has shifted downwards is related to the distance to that galaxy.

Answer 7

Parallax is an apparent displacement or difference of orientation of an object viewed along two different lines of sight, and is measured by the angle or semi-angle of inclination between those two lines.[1][2] The term is derived from the Greek παράλλαξις (parallaxis), meaning "alteration". Nearby objects have a larger parallax than more distant objects when observed from different positions, so parallax can be used to determine distances. In astronomy, parallax is the only direct method by which distances to objects (typically stars) beyond the Solar System can be measured. The Hipparcos satellite has used the technique for over 100,000 nearby stars. This provides the basis for all other distance measurements in astronomy, the cosmic distance ladder. Here, the term "parallax" is the angle or semi-angle of inclination between two sightlines to the star.

Answer 8

For nearby stars, the parallax method is used. For stars that are farther away - star groups, actually, such as clusters or galaxies - one of several "standard candle" method is used, that is, for certain objects of known brightness, the real brightness is compared to the apparent brightness.

Answer 9

Take a picture of the sky (at night of course). Six months later take another picture of the same piece of sky. Compare the two picture.

Now; most of the objects are so far away that they seem "fixed", but the nearer ones will appear to have moved. Knowing the base line (186 million miles) the distance to those objects can be calculated.

Answer 10

Red shift is a good guide to a stars distance from us. If you sample the light from a star and pass it through a diffraction grating a spectrum of its light from red to violet is created. Within the spectrum dark lines caused by the elements present in the star's atmosphere are compared to light from a nearby star. These lines are equivalent to a bar code and are usually shifted towards the red end of the spectrum. The extent of this shift required to align these bar codes is a measure of it's distance from us. Edwin Hubble derived his 'Hubble Constant' to estimate these huge distances. The further into the red, the farther away a star is.