Description

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Context

In 1986, NASA’s Voyager 2 spacecraft flew close to Uranus to collect data. During its five-day visit, Voyager 2 sent back important information that shaped how we understand this distant planet.

However, scientists have now realized that some of the information from this visit might not be completely accurate due to unusual conditions at the time.

About Uranus

In 1781, William Herschel, a German-born British astronomer, discovered Uranus with a telescope. This made Uranus the first planet to be found using this technology.

Uranus is the third largest planet in our solar system.

Feature	Details
Position in Solar System	7th planet from the Sun, located between Saturn and Neptune.
Size	Uranus has a diameter of about 51,118 km, making it four times the width of Earth.
Distance from Sun	Approximately 1.8 billion miles (2.9 billion km) away from the Sun.
Day and Year	A day lasts about 17 hours, while a year (one full orbit around the Sun) takes 84 Earth years.
Rotation	Uranus spins on its side, almost 90 degrees compared to other planets, which creates unique seasons and extreme weather.
Atmosphere	Made mostly of hydrogen, helium, and methane, giving it a blue-green color. The methane absorbs red light, making it appear blue.
Temperature	Uranus is one of the coldest planets, with temperatures dropping to around -224 degrees Celsius.
Rings	Has 13 faint rings, with inner rings that are narrow and dark, and outer ones brighter and wider.
Moons	There are 28 known moons, named after characters from works by Shakespeare and Alexander Pope, like Titania and Oberon.
Potential for Life	Due to extreme cold, pressure, and atmospheric conditions, Uranus is unlikely to support life as we know it.

Findings

The solar wind is a stream of high-speed particles that flow out from the sun. This solar wind can affect planets, especially their magnetic fields.

When Voyager 2 visited Uranus, it was just after a strong solar wind event, which compressed Uranus’s magnetic field, or "magnetosphere," to only 20% of its usual size. This change in the magnetosphere led to unusual observations.

The compressed magnetosphere made scientists think that Uranus had very little plasma (a high-energy state of matter) and unusually strong electron belts.

Magnetosphere

A magnetosphere is the region around a planet dominated by the planet's magnetic field. Other planets in our solar system have magnetospheres, but Earth has the strongest one of all the rocky planets: Earth's magnetosphere is a vast, comet-shaped bubble, which has played a crucial role in our planet's habitability.

Plasma

Plasma, which is a mix of high-energy particles, usually fills a planet’s magnetosphere and comes from sources like the solar wind or the planet’s moons.

Read about plasma: https://www.iasgyan.in/daily-current-affairs/plasma-the-fourth-state-of-matter

This new information might help scientists discover hidden oceans under the surfaces of these moons by studying their magnetic environments.

Voyager 2’s Mission

Voyager 2 is a space probe launched by NASA on August 20, 1977, as a part of the Voyager program. It was launched on a trajectory towards the gas giants Jupiter and Saturn and enabled further encounters with the ice giants Uranus and Neptune.

It remains the only spacecraft to have visited either of the ice giant planets and was the third of five spacecraft to achieve Solar escape velocity, which allowed it to leave the Solar System.

Voyager 2 successfully fulfilled its primary mission of visiting the Jovian system in 1979, the Saturnian system in 1981, Uranian system in 1986 and the Neptunian system in 1989. The spacecraft is now in its extended mission of studying the interstellar medium. It is at a distance of 138.05 AU from Earth as of October 2024.

Read about Voyager 2 in detail: https://www.iasgyan.in/daily-current-affairs/voyager-2

Read about Voyager 1 in detail: https://www.iasgyan.in/daily-current-affairs/voyager-1

Sources:

Hindu

PRACTICE QUESTION

Q.Consider the following statements about plasma:

Plasma is the most abundant state of matter in the visible universe.
It consists of free electrons and ions, allowing it to conduct electricity.
Plasma can exist naturally only in stars and is not found on Earth.

Which of the statements given above is/are correct?

(a) 1 and 2 only

(b) 2 only

(d) 1, 2, and 3

Answer: (a)

Explanation:

Statement 1 is correct. Plasma is the most abundant state of matter in the visible universe found in stars, interstellar space and other astronomical objects. Most of the matter in the universe exists in this ionized state.

Statement 2 is correct. Plasma is composed of free electrons and positively charged ions making it electrically conductive. This conductivity allows it to respond to magnetic and electric fields distinguishing it from neutral gases.

Statement 3 is incorrect. While plasma naturally occurs in stars, it is also found on Earth in various forms, such as in lightning, flames and certain artificial applications like neon lights and plasma displays. Therefore, plasma is not exclusive to stars.