Neptune is in a nearly circular orbit at 30.06 AU from the Sun, while the Earth is in a nearly circular orbit at 1 AU. So the closest point between the Earth and Neptune is about 29 AU, while the farthest distance is about 31 AU. As of today (December 8, 2008) Neptune is 30.44 AU away from Earth.
The FREE, Open-Source planetarium program Stellarium is available for Linux, Windows or Mac from www.stellarium.org.
The Nine Planets web site (link below) will give you the orbital distances of each of the planets in kilometers. You can easily convert kilometers to Astronomical Units by dividing the orbital distance by 149,598,000. This is the number of km in one AU.
Or, you can use the calculator built into Google.
Neptune is about 30 AU from the Sun. The distance from the Earth can be up to 1 AU more or less, depending on which side of the Sun the Earth is (in relation to Neptune).
I calculate 57.7 of them.
About 18.375AU from the Sun.
Approx 30 AU.
Jupiter
Mars of course.....
Earth is 1 AU from the Sun. There is no planet at an orbit of 2.5 AU. (Mars orbits at 1.5 AU and Jupiter at 5.2 AU).
Venus' aphelion is 0.728 231 28 and its perihelion is 0.718 432 70 AU with a semi majour axis of 0.723 332 AU.
Jupiter is the fifth planet from the Sun, located about 4.95 astronomical units (AU) away. This is 483,800,000 miles and 778,500,000 kilometers.
Mercury: 0.387 AU Venus: 0.723 AU Earth: 1.000 AU Mars: 1.524 AU Jupiter: 5.204 AU Saturn: 9.582 AU Uranus: 19.229 AU Neptune: 30.104 AU
Jupiter is roughly 5.2 AU from the sun.
Uranus is around 19 AU from the sun, theres no planet that is 1.9 AU from the sun. the closest to this is Mars, at 1.5 AU.
Venus is 0.723332 AU (semi-major axis) from the Sun.
Planet Saturn is 9.5 au's away from the sun. An au is astronomical unit used to measure distances from a planet to the sun.
No planet so far observed or detected is that far from the Sun. The furthest planet so far observed is Neptune at about 30 AU.
Mercury averages about 0.35 AU from the Sun, and Saturn is about 9.5AU from the Sun. So depending on where each planet is in its orbit (or more specifically, where Mercury is in its orbit) Saturn will be anywhere from 9.2 AU to 9.8 AU from Mercury.
Jupiter
neptune
About 5,2 times that average distance from the Earth to the Sun (or 5,2 AU)
Jupiter
Mars of course.....