The giant planets orbit the Sun far beyond the orbits of Earth and Mars. The closest to the Sun is Jupiter, more than 5 times as far from the Sun as Earth is. At this distance the Sun is very faint and provides very little warmth. From Jupiter, the Sun appears to be a tiny disk, 1/27 as bright as it appears from Earth. Neptune, the most distant giant planet, is 4.5 billion kilometers (km) away, or some 30 times farther from the Sun than Earth is. If you were traveling at the speed of a commercial jetliner, it would take you more than 500 years to reach Neptune. From Neptune, the Sun is just a point of light in the sky, like other stars, though about 500 times brighter than the full Moon is in Earth’s sky. This level of brightness means that daytime on Neptune is only as bright as twilight on Earth. With so little sunlight available for warmth, daytime temperatures hover around 123 kelvins (K) at the cloud tops on Jupiter, and they can dip to just 37 K on Neptune’s moon Triton.