When was uranus formed

Some of the larger rings are surrounded by belts of fine dust. Uranus took shape when the rest of the solar system formed about 4. Like its neighbor Neptune, Uranus likely formed closer to the Sun and moved to the outer solar system about 4 billion years ago, where it is the seventh planet from the Sun. Uranus is one of two ice giants in the outer solar system the other is Neptune. Near the core, it heats up to 9, degrees Fahrenheit 4, degrees Celsius. Uranus is slightly larger in diameter than its neighbor Neptune, yet smaller in mass.

It is the second least dense planet; Saturn is the least dense of all. Uranus gets its blue-green color from methane gas in the atmosphere. Sunlight passes through the atmosphere and is reflected back out by Uranus' cloud tops. Methane gas absorbs the red portion of the light, resulting in a blue-green color. The planet is mostly swirling fluids. The extreme pressures and temperatures would destroy a metal spacecraft. Uranus' atmosphere is mostly hydrogen and helium, with a small amount of methane and traces of water and ammonia.

The methane gives Uranus its signature blue color. While Voyager 2 saw only a few discrete clouds, a Great Dark Spot, and a small dark spot during its flyby in — more recent observations reveal that Uranus exhibits dynamic clouds as it approaches equinox, including rapidly changing bright features. Uranus' planetary atmosphere, with a minimum temperature of 49K Wind speeds can reach up to miles per hour kilometers per hour on Uranus.

But closer to the poles, winds shift to a prograde direction, flowing with Uranus' rotation. Uranus has an unusual, irregularly shaped magnetosphere. Magnetic fields are typically in alignment with a planet's rotation, but Uranus' magnetic field is tipped over: the magnetic axis is tilted nearly 60 degrees from the planet's axis of rotation, and is also offset from the center of the planet by one-third of the planet's radius.

Keck Observatory. Although Saturn is best known for its elaborate ring system, all of the giant planets in our solar system have rings of their own. Uranus has 13 distinct rings made up of very dark particles, quite different from Saturn's rings, which are mostly water ice. Scientists believe that Uranus's rings formed after the planet took shape, from the leftovers of destroyed moons. The rings are tilted about 90 degrees and match Uranus's rotation.

Launched in to explore the outer solar system, NASA 's Voyager 2 was the only spacecraft to fly relatively close to Uranus. It surveyed the planet from a distance of about 80, km in before moving on to the neighbouring ice giant, Neptune. During its short observation of Uranus, the probe studied the planet's atmosphere, magnetic field, ring system and many of its moons. The spacecraft's observations even helped scientists discover 10 of the planet's natural satellites.

Oberon and Titania are the largest Uranian moons, and were the first to be discovered, by Herschel in William Lassell, who was also the first to see a moon orbiting Neptune, discovered Uranus' next two moons, Ariel and Umbriel. In , Voyager 2 visited the Uranian system and discovered an additional 10 moons, all just 16 to 96 miles 26 to km in diameter:Juliet, Puck, Cordelia, Ophelia, Bianca, Desdemona, Portia, Rosalind, Cressida and Belinda.

Each of those moons are roughly half water ice and half rock. Since then, astronomers using Hubble and ground-based observatories have raised the total to 27 known moons, and spotting these was tricky — they are as little as 8 to 10 miles 12 to 16 km across, blacker than asphalt and nearly 3 billion miles 4.

Between Cordelia, Ophelia and Miranda is a swarm of eight small satellites crowded together so tightly that astronomers don't yet understand how the little moons have managed to avoid crashing into each other.

Anomalies in Uranus' rings lead scientists to suspect there might still be more moons. In addition to moons, Uranus may have a collection of Trojan asteroids — objects that share the same orbit as the planet — in a special region known as a Lagrange point. The first was discovered in , despite claims that the planet's Lagrange point would be too unstable to host such bodies. Although there isn't a spacecraft on its way to Uranus at the moment, astronomers regularly check in with the planet using the Hubble and Keck telescopes.

And in , NASA suggested a number of potential future missions to Uranus in support of the forthcoming Planetary Science Decadal Survey, including flybys, orbiters and even a spacecraft to dive into Uranus' atmosphere. Scientists are still discussing the idea. At that relatively low cost, the mission would perform minimal science, but could still include items such as a magnetometer, a methane detector and a camera.

Unlike most gas giants, Uranus has a core that is rocky rather than gaseous. The core likely formed first, and then gathered up the hydrogen, helium and methane that make up the planet's atmosphere. Heat from the core drives Uranus' temperature and weather, overpowering the heat coming from the distant sun , which is almost 2 billion miles away. Some exoplanet observations seem to confirm core accretion as the dominant formation process.

Stars with more "metals" — a term astronomers use for elements other than hydrogen and helium — in their cores have more giant planets than their metal-poor cousins.

According to NASA , core accretion suggests that small, rocky worlds should be more common than the more massive gas giants. The discovery of a giant planet with a massive core orbiting the sun-like star HD is an example of an exoplanet that helped strengthen the case for core accretion. Henry, an astronomer at Tennessee State University, Nashville, detected the dimming of the star.

Studying these distant worlds may help determine how planets in the solar system formed. But the need for a rapid formation for the giant gas planets is one of the problems of core accretion. According to models, the process takes several million years, longer than the light gases were available in the early solar system. At the same time, the core accretion model faces a migration issue, as the baby planets are likely to spiral into the sun in a short amount of time.

According to a relatively new theory, disk instability, clumps of dust and gas are bound together early in the life of the solar system. Over time, these clumps slowly compact into a giant planet. These planets can form faster than their core accretion rivals, sometimes in as little as a thousand years, allowing them to trap the rapidly-vanishing lighter gases. They also quickly reach an orbit-stabilizing mass that keeps them from death-marching into the sun.