what is a parallax in science terms?

Answer 1

An apparent change in the direction of an object, caused by a change in observational position that provides a new line of sight.

Here is a link.

http://www.answers.com/topic/parallax

This term is often used in astronomy.

The apparent angular displacement of a celestial object due to a change in the position of the observer. With a baseline of known length between two observations, the distance to the object can be determined directly.

The rotation of the Earth or the linear separation of two points on its surface can be used to establish distances within the solar system. The parallax determined is scaled to the equatorial radius of the Earth, which is equal to 6378 km (3963 mi). At the mean distance of the Moon, this baseline subtends an angle of 57′02.61′′, and at the mean distance to the Sun it amounts to 8.794148′′. This latter distance is defined as the astronomical unit and serves as a measure of distances within the solar system. One astronomical unit is 149,597,870.66 ± 0.02 km (92,955,807.25 ± 0.01 mi) in length, and its high precision results from tracking interplanetary space probes.

The astronomical unit is the baseline for the measure of stellar parallaxes or distances and ultimately every other distance in the universe outside the solar system. Observations made from the Earth in its orbit on opposite sides of the Sun are scaled to the astronomical unit. The stellar parallax is given in units of arc-seconds and is by definition the reciprocal of the distance in parsecs. One parsec is the distance at which one astronomical unit subtends an angle of one second of arc and equals 206,264.8 astronomical units or 3.2616 light-years.

Answer 2

it particularly is a distinction interior the apparent course, because of the baseline used for 2 observations. Our suggestions makes use of the image from the two eyes. The baseline is the gap between the eyes. each and each eye sees a particularly diverse scene. A post planted in a field in front of a miles off row of homes would look lined up with the pink homestead for the left eye yet lined up with the blue homestead as considered by the appropriate eye. The suggestions (used to the gap between the eyes) will promptly interpret this distinction as "the post is closer than the homes" and would even permit you wager on the gap (as much as approximately 20 metres or 60 ft for many folk). the sought after version in astronomy is to take photographs of an merchandise suspect to be closer than the "fastened" stars at one ingredient, then take yet another image six months later, after the Earth has moved to the different side of its orbit (the baseline is two astronomical instruments). in actuality, many photographs are taken over a a lot longer era, in case the item has its own "suited action". by measuring the region of the item relative to very distant stars (assumed to not be affected, like the distant row of homes earlier), we are in a position to degree the version in obvious place -- as an attitude. We take 0.5 this fee (to make the baseline a million astronomical unit) and degree it in seconds of arc (one 2nd = a million/3600 of a level). this offers us the parallax attitude of the item. For stars, it particularly is often smaller than a million". We take the inverse of this attitude (a million/x) and the effect is the gap in a unit pronounced as "parsec" (from "parallax 2nd"). One parsec is approximately 3.26 mild-years. as an occasion, the parallax attitude for the megastar Sirius is 0.379" and if we calculate the inverse of that attitude (a million / 0.379) we get approximately 2.sixty 4 parsecs for a distance (2.sixty 4 * 3.26 = 8.6 mild-years). Tables record Sirius as being 9 mild-years away so because it particularly is approximately good.

Answer 3

northstar gave a great answer. but there is a way to think of parralax on a more human scale (although his answer may have been more what you were looking for). the driver of a car reads his speedometer. he gets a value. the passenger looks at the same speedometer but reads a different one. that is because the angle/direction at which the passenger is reading the meter is different