Results from NASA NEOWISE survey find that more potentially hazardous asteroids, or PHAs, are closely aligned with the plane of our solar system than previous models suggested.
The Face of Beauty
Image of boulders on the surface of the asteroid Dimorphos as seen by DART prior to impact.

Studying Our Solar System

Understanding the planets and small bodies of our solar system helps answer questions about its formation, how it reached its current diverse state, how life evolved on Earth and possibly elsewhere, and what characteristics of the solar system lead to the origins of life.

Inner Solar System

Inner solar system bodies are rocky, unlike the gas and water giant planets of the outer solar system. Rocky planets Mercury, Venus, Earth and Mars are thought to have formed from the accumulation of dust into small planetesimals, then the planetesimals into proto-planets and, finally, the proto-planets into planets. Many details of this sequence are still unknown.

Although Venus, Earth, and Mars are similar, they evolved differently. For example, we know that Mars once had water on its surface, and there are hints that Venus may have, too, but Earth is the only planet known to be habitable.

Rocky planets
Data from VERITAS about the surface and interior of Venus will help scientists make useful comparisons between the four rocky planets of our solar system (Mercury, Venus, Earth, and Mars), as well as rocky exoplanets.

Outer Solar System

The outer solar system consists of four “gas giants”: Jupiter, Saturn, Uranus, and Neptune. These four planets do not have a defined surface. Jupiter and Saturn consist mostly of hydrogen and helium. Uranus and Neptune consist mostly of water, methane, and ammonia, and they are sometimes referred to as the “water giants.”

At a certain point in their atmospheres, the gas on these planets transitions, or condenses, to a liquid state. Jupiter and Saturn probably have rocky cores surrounded by metallic hydrogen. Uranus and Neptune are composed of rock, water, methane, and ammonia, but their outer atmospheres are comprised of hydrogen, which is similar to Jupiter and Saturn.

More than 100 moons in total orbit these planets of the outer solar system. Saturn’s ring system is thought to be a pulverized moonlet.

Illustration showing scale of all four giant planet. Jupiter is largest followed by Saturn. Uranus and Neptune are similar in size.
The orbits of all four giant planets of our solar system may have shifted early on, creating the Kuiper Belt while also ejecting lots of other icy objects.

Small Bodies

The small bodies of the solar system include comets, asteroids, objects in the Kuiper Belt and the Oort cloud, small planetary satellites, Triton, Pluto, Charon, and interplanetary dust. Some of these objects are believed to be almost unchanged since the young solar nebula formed our solar system 4.6 billion years ago. Because of this, they may provide insight into the evolution of the planets and other bodies of the solar system.

This image shows comet C/2018 Y1 Iwamoto as imaged in multiple exposures of infrared light by NASA's Near-Earth Object Wide-field Survey Explorer (NEOWISE) space telescope.
Comet C/2018 Y1 Iwamoto as imaged in multiple exposures of infrared light by the NEOWISE space telescope. The infrared images were taken on Feb. 25, 2019, when the comet was about 56 million miles, or 90 million kilometers, from Earth. C/2018 Y1 Iwamoto is a long-period comet originally from the Oort Cloud and coming in near the Sun for the first time in over 1,000 years. Appearing as a string of red dots, this comet can be seen in a series of exposures captured by the spacecraft. Infrared light detected by the 3.4-micron channel is mapped to blue and green, while light from the 4.6-micron channel is mapped to red. In this image, stars show up as blue because they are hotter, whereas the cooler dust around the comet - with a temperature near the freezing point of water - glows red. Movie available at
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