Top 8 largest objects in the universe

Astronomers have discovered some of the most massive celestial objects in the universe, from planets to superclusters of galaxies .

The Truth About the Largest Objects in the Universe

1. Largest planet: ROXs 42Bb

Simulation of planet ROXs 42 Bb. (Photo: NASA).

Jupiter, which is 11 times larger than Earth in radius, is the largest planet in the Solar System. ROXs 42Bb is the largest planet found in the Universe. It has a mass 9 times that of Jupiter and a radius 1.12 times that of Jupiter. ROXs 42 Bb is 440 light years away from Earth. Because it is located outside the Solar System, it is classified as an exoplanet.

Thayne Currie, an astronomer at the University of Toronto, first identified ROXs in 2013. It is a gas giant similar to Jupiter. While Earth and Jupiter take 365 days and 12 years, respectively, to orbit the Sun, ROXs 42 Bb completes one orbit around its star every 1,968.3 years.

2. Biggest star: UY Scuti

Simulation of the star UY Scuti. (Photo: Pixabay/Pexels).

More than a million Earths could fit inside the Sun, but the largest star in the universe, UY Scuti, is so massive that it could contain 5 billion stars with the volume of the Sun. If UY Scuti were at the center of the solar system, its outer shell, the photosphere, would extend beyond the orbit of Jupiter. The supergiant star, located 9,500 light-years from Earth, was first described in 1860 by a team of astronomers from the Bonn Observatory in Germany. Even 160 years after its discovery, astronomers have yet to find a larger star.

UY Scuti is classified as a variable star because it experiences fluctuations in brightness every 740 days. Scientists speculate that it is currently in the phase where it will run out of hydrogen fuel in its core and expand into a red supergiant. This means that it could be on track to explode as a supernova, marking the end of its existence. However, researchers do not know exactly when UY Scuti will explode.

3. The largest star system

The largest star system in the universe in terms of orbit consists of just one planet (2MASS J2126) orbiting the star TYC 9486-927-1 . Seven years ago, astronomers didn't even know the star and planet were connected. The two were considered free-floating objects, located 1,000 billion kilometers apart in space.

However, in 2016, an international team of researchers identified the giant orbit of 2MASS J2126 and discovered a planet orbiting TYC 9486-927-1. The distance between Earth and this unique star system is 104 light years. The orbit of 2MASS J2126 is 140 times wider than the orbit of Pluto in the Solar System. Apart from its extremely wide orbit and large distance from its host star, 2MASS J2126 takes nearly 900,000 Earth years to complete one orbit.

4. Largest galaxy: IC 1101

Galaxies are collections of star systems. Some reports say the universe contains about 2 trillion galaxies. These massive bodies contain billions of stars and many other celestial bodies. For example, the Milky Way is estimated to contain 100 billion stars and nearly 100 million black holes.

However, that number pales in comparison to IC 1101 , the largest galaxy in the universe in terms of size. IC 1101 is 50 times larger and 2,000 times more massive than the Milky Way. Astronomers believe it is home to 100 trillion stars and spans 6 million light years. In contrast, the Milky Way is only about 100,000 light years across. Some experts speculate that IC 1001 may have formed from multiple galaxies colliding and merging.

5. Largest black hole: TON 618

The largest black hole in the universe is estimated to be 66 billion times more massive than the Sun. This supermassive black hole powers a quasar (extremely bright object) called TON 618, which has the luminosity of 140 trillion Suns. Located 18.2 billion light-years from Earth, TON 618 was first discovered in 1957.

6. The Largest Stellar Nursery: The Tarantula Nebula

Tarantula Nebula. (Photo: NASA)

Nebulae are giant clouds of gas and dust in space where new stars form due to the effects of gravity, temperature and pressure changes, and thermonuclear fusion. The Tarantula Nebula, also known as 30 Doradus, is one of the largest and brightest known nebulae, according to NASA. It covers an area 1,800 light-years across the universe and is 170,000 light-years from Earth. The Tarantula Nebula was discovered in the early 1750s by French astronomer Nicolas-Louis de Lacaille. However, telescopes at the time were not advanced enough to detect individual stars and other structures within the nebula. It wasn't until more than 200 years later, when astronomers took high-resolution images of the Tarantula, that they realized its massive size.

7. Largest galaxy cluster: El Gordo

In 2012, NASA's Chandra X-ray Observatory identified an extremely large galaxy cluster called ACT-CLJ0102-4915. When astronomers calculated its mass, the results were surprising. ACT-CLJ0102-4915's mass is estimated to be 3 quadrillion times that of the Sun. It is the largest galaxy cluster ever discovered and has been nicknamed El Gordo, meaning "the fat one."

Astronomers speculate that it may have formed when two massive galaxy clusters crashed into each other in space at millions of kilometers per hour. El Gordo also contains the longest observable galaxy, La Flaca.

8. The largest entity in the universe: The Great Wall of Hercules - Corona Borealis

The Great Wall of Hercules - Corona Borealis. (Photo: Pablo Carlos Budassi/Wikimedia Commons).

Measuring 6 to 18 billion light years across, the Great Wall of Hercules is believed to be the largest observable entity in the universe. It is a cluster of galaxies bound together by gravity. The size of this supercluster is so large that it takes light about 10 billion years to travel its entire length. The Great Wall of Hercules was discovered in 2013 while mapping gamma-ray bursts, the most energetic form of light.