what is parallax angle?
Answers
Explanation:
The parallax angle is the angle between the Earth at one time of year, and the Earth six months later, as measured from a nearby star. Astronomers use this angle to find the distance from the Earth to that star. ... Because of this, nearby stars will seem to move relative to distant, "background" stars.
Answer:
The parallax angle is the angle between the Earth at one time of year, and the Earth six months later, as measured from a nearby star. Astronomers use this angle to find the distance from the Earth to that star. How do scientists measure this angle, and how does this information tell them the distance to the star?
The Earth revolves around the Sun every year, so that every half year (six months) it is on the opposite side of the sun from where it was six months ago. Because of this, nearby stars will seem to move relative to distant, "background" stars. You can see this effect driving in the country. Nearby road signs seem to move by quickly, but distant buildings/trees/etc
To do this, the astronomers use a method similar to the one you used with your homemade quadrant. Twice the distance to the Sun, divided by the distance to the star (which is unknown so far) is equal to the tangent of the parallax angle of the star.
tan (angle) = 2 AU/ distance
or
distance = 2 AU/ tan (angle)
(1 AU is the distance from the Earth to the Sun)
