Neptune in Motion

To commemorate Neptune’s first complete orbit around the sun since its discovery in 1846, NASA has released “anniversary images” that reveal all the faces that the planet displays during each of its 16-hour rotations. The images were taken using the Hubble Space Telescope on June 25-26.

An animation showing Neptune spinning on its axis
Sean Walker, S&T's imaging editor put together this spinning image of Neptune from four Hubble images released to commemorate the planet's first complete orbit around the sun since its discovery. The images were taken on June 25-26, over an 11-hour period.
NASA/HST/Sean Walker
Sean Walker, Sky & Telescope’s Imaging Editor, mapped the Hubble images onto a sphere and used software to rotate it. The resulting video shows what the planet would look like if we could see it close up with infrared-sensitive eyes.

The images are close to natural color, but use blue, red, and near-infrared data to reveal clouds in the gas giant's upper-atmosphere. Neptune’s methane-rich atmosphere, which absorbs the red wavelengths, gives the planet its blue-green hue. The clouds, however, are tinted pink because of the reflection of near-infrared light. For comparison, a natural color image taken by Hubble last August can be seen here.

Neptune has an axial tilt of 28&frac12°, so it experiences seasons much like Earth's. But each season on Neptune lasts about 40 years. These images show the planet in a phase of transformation: clouds, which were brooding over the southern skies a few years ago, are now beginning to gather in the north. This shows that spring is approaching north of Neptune’s equator and summer is waning to its south.

If you have good binoculars or a small telescope, you can spot the blue planet late at night using our Neptune finder chart.

A recent study suggests that scientists may have gotten Neptune's rotational rate wrong for decades. Click here for the latest news on Neptune's spin.

2 thoughts on “Neptune in Motion

  1. Anthony Barreiro

    This is an awesome video, it really gives me a sense of watching Neptune turn on his axis. It seems like the pole closer to the bottom left of the frame is more illuminated than the pole at the upper right. Is this correct? Is the bottom pole the north pole? That would seem to be the case if it’s northern spring and southern autumn.

  2. Ali

    I read this paragraph in two other websites:

    "It is early summer in the southern hemisphere and winter in the northern hemisphere."

    But I think it is not compatible with your text:

    "This shows that spring is approaching north of Neptune’s equator and summer is waning to its south."

    Am I right?

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