Earth's Visibility On January 31, 2012, Eros passed Earth at 0.17867 AU (26,729,000 km; 16,608,000 mi), about 70 times the distance to the Moon, with a visual magnitude of +8.1. Viewing this event from anywhere on Earth, including the center of the planet, was possible with binoculars or a small telescope.
Eros is one of many small bodies that make up the asteroid belt between Mars and Jupiter. It has an estimated diameter of about 350 m (1150 ft). Eros is also known as 22 Psyche.
Astronomers use telescopes on land and in space to study objects across the universe. They often look for changes over time in these objects which may help scientists understand how they form and evolve. Objects like Eros that are close to Earth appear as a bright point of light against a dark background, such as the night sky. As telescopes get better, they can see fainter objects and observe them over longer periods of time.
In 1995, astronomers using the Hubble Space Telescope discovered evidence of water vapor on Eros. They found that the surface contained streaks that appeared to be formed by liquid flowing down Eros' slope.
It is also possible to see Eros with the naked eye on clear, dark nights.
Eris has a radius of around 722 miles (1,163 kilometers), which is approximately one-fifth the radius of Earth. The difference is due to Eris having more mass per unit area.
Earth's mass is 5.972 x 10^24 kg (12.91 billion tons). Eris' mass is 9.45 x 10^25 kg (20.74 billion tons). That's a difference of 1.63 x 10^26 kg (3.51 billion tons) or 16.30% of Earth's mass.
This means that if Eris were placed at Earth's center, it would be able to pull Earth in towards itself and cause an explosion of about 16 percent of its current volume. This isn't likely to happen because gravity doesn't work like that, but it shows how massive Eris is compared to Earth.
Earth's average density is 3,000 kg/m^3. Eris averages 8,000 kg/m^3.
The largest satellite we have ever discovered is Jupiter's moon, Ganymede. It is almost as large as Earth itself and so could certainly hold its own against Eris should they ever come into contact.
We cannot view Eris with the naked eye or with binoculars in the same way that we can see Mars or Jupiter because it is so far away. To observe it, you'll need a strong telescope and a lot of amateur astronomy knowledge, so don't anticipate it to be in our sky guide anytime soon! Eris has an average visual magnitude of +15.3, making it one of the brighter stars in the constellation Orion.
Eris was first spotted by American astronomer William Herschel using a telescope made from a hollowed-out pumpkin shell on April 23, 1790. At that time, it was traveling through space at a speed of about 20 miles per second away from the Sun. By measuring the distance between Eris and other stars known at the time, Herschel was able to calculate its absolute magnitude (the measure of how bright it appears from Earth). He found that it was much more luminous than any other star he could see with his eyes alone, which led him to name it "asteroid" (an astronomical body composed mainly of rock and metal) instead of a planet (a celestial body considered to be a major part of the Solar System).
Herschel's observations were later confirmed by French astronomer Jean-Philippe Marthon who also discovered Proteus, another star near Eris. In 1791, German astronomer Friedrich Wilhelm Bessel observed Eris as well and determined its exact position in the galaxy.
The photograph was captured on January 1, 2019, at 5:26 UT (12:26 a.m. EST), when the spacecraft was 4,109 miles (6,628 kilometers) from Ultima Thule and 4.1 billion miles (6.6 billion kilometers) from Earth. The "phase angle" between the spacecraft, Ultima Thule, and the Sun was 33 degrees. Images taken during this alignment show features on both Ultima Thule and its largest moon, Charon.
Ultima Thule is a name given to any object beyond the solar system's Kuiper belt. Although many theories have been proposed for what may lie beyond the solar system's asteroid belt, no other objects are known to exist there at this time. The term "Ultima Thule" comes from the Latin word for "far beyond."
In 1610, William Shakespeare wrote, "From nothing nothing can be created." This famous quote is often misattributed to Albert Einstein, who supposedly said, "Nothing can be created out of nothing." However, as early as 1572, Nicolas Copernicus published his book On the Revolutions of the Heavenly Spheres, in which he included a chapter titled "On the Mutability of the World," in which he discussed how impossible it would be for anything to come into existence from nothingness.
In 1919, American astronomer Carl Wilhelm Ostenfeld coined the term "planet X" to describe an unknown body that might lie in space beyond Neptune.
Dwarf Planet 136199 Eris is now 14,293,004,674 kilometers away from Earth, which equates to 95.542835 astronomical units. Light travels from Dwarf Planet 136199 Eris to us in 13 hours, 14 minutes, and 36.3317 seconds.
Eris's orbit around the Sun is highly elliptical, with a major axis of 545.5 miles (885 km). At its most distant point, it takes Eris about 665 years to travel once around the Sun. At its closest point, it only takes Eris about 453 days to circle the center of the Solar System. Its average distance from the Sun is about 547 million miles (894 million km), or about 1.9 times that of Earth.
Eris was discovered on January 4, 2005 by scientists using data from NASA's New Horizons spacecraft, who were investigating observations of Pluto made by the craft several days earlier. They determined that the object responsible for the signals was beyond Pluto, but could not identify it with certainty until later that year, when they learned it was Eris.
The size of Eris has been a subject of debate since its discovery. Estimates range from 1095 to 2722 miles (1780 to 4430 km) in diameter, making it larger than either Earth or Mars but smaller than Ceres which is 3069 miles (4940 km) in diameter.
Dwarf Planet 136199 Eris is now 14,493,742,710 kilometers away from Earth, which equates to 96.884686 astronomical units. Light travels from Dwarf Planet 136199 Eris to us in 13 hours, 25 minutes, and 45.9217 seconds.
Eris's average surface temperature is -171 degrees Celsius. It has one moon named Nix that is not as big as Earth's Moon but it exists.
Eris was discovered on January 4, 2005 by American astronomers Chad Trujillo and David L. Hogg at Apache Point Observatory in New Mexico. The two scientists were looking through data collected by the Lowell Discovery Telescope when they spotted Eris. They called the team who confirmed its presence later that day.
Eris is the largest member of a group of objects called "dwarf planets". These objects do not reach the distance from the Sun where water can be found on their surfaces, but they are still considered planets because they orbit the Sun like all other planets.
The term "dwarf planet" was coined in 2006 by astronomer Michael Brown of the California Institute of Technology. He argued that Eris and other small Solar System bodies should be classified as planets even though they do not meet the conventional definition of this word.
14,321,968,975 km Dwarf Planet 136199 Eris is now 14,321,968,975 kilometers away from Earth, which equates to 95.736449 astronomical units. Its orbit is quite eccentric, with a perihelion distance of 5,584,000 km and an aphelion distance of 22,943,000 km.
Eris was discovered on February 18th, 2005 by Richard Kowalski at the Palomar Observatory in California, USA. The discovery was confirmed two days later by another team led by Elisa Vida of the Institute for Astronomy of the University of Hawaii at Manoa.
It has an orbital period of 442.8 years and an average distance from the Sun of 5.67 billion km. The size of Eris has not yet been directly measured, but it has been estimated to be between 940 and 990 miles (1,542-1,646 kilometers) in diameter based on its gravitational pull.
Eris is one of several dwarf planets found using computer algorithms that analyze data from NASA's Hubble Space Telescope. The others include Pluto, Chiron, Nix, and Isis.
Of all the known dwarf planets, Eris is the largest and most massive body in the Solar System.