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Distance to the Great Attractor

The Great Attractor is a region of space whose gravity pulls the Milky Way and thousands of other galaxies toward it. It lies near the Norma and Centaurus clusters of galaxies, and its center is about 230 million light-years from Earth. A light-year is the distance light travels in one year, about 9.46 trillion kilometers.

Distance

The Great Attractor was found from the way galaxies move. In 1988 a team of seven astronomers studied 400 elliptical galaxies across the sky. After allowing for the expansion of the universe, they found the galaxies streaming toward one region. They placed its center at the distance where the expansion carries galaxies away at about 4,350 kilometers per second.

Recent measurements give the distance directly, in megaparsecs. A megaparsec is a million parsecs, about 3.26 million light-years. In 2021, a study put the Norma cluster, the richest cluster in the region, 69.7 megaparsecs away. In 2026, a study using an especially accurate method found the flow of galaxies toward the Great Attractor fading to zero about 70 megaparsecs from the Local Group, the group that includes the Milky Way.

Both results put the center about 230 million light-years away. Both also find the galaxies there barely moving apart from the expansion, as expected at the center of the pull.

The center is still known only roughly. As seen from Earth it lies behind the disk of the Milky Way, where dust and crowded stars hide much of the view. Astronomers study the region in infrared light, which passes through dust more easily.

Size comparisons

  • The Great Attractor's center is about four times as far away as the Virgo Cluster, the nearest large cluster of galaxies, which is about 54 million light-years away.
  • It is about 90 times the distance from the Milky Way to the Andromeda Galaxy.
  • About 2,300 Milky Ways, each about 100,000 light-years across, would stretch from Earth to the Great Attractor.
  • The core of the Shapley Supercluster, which lies beyond it in a similar direction, is about three times as far away.
  • If the Milky Way were shrunk to the size of a basketball, the Great Attractor's center would be about 550 meters (1,800 feet) away, about a third of a mile.

How strong the pull is

The Local Group moves at about 630 kilometers per second compared with the cosmic microwave background, the faint glow left over from the early universe. The 1988 team estimated that the Great Attractor holds about 54 million billion times the mass of the Sun more than an average region of its size. That is enough to pull the Sun's neighborhood toward it at about 570 kilometers per second. They estimated that the crowd of galaxies there is some 20 times as populous as the Virgo Cluster.

In 2014, astronomers mapped the motions of galaxies to define the Laniakea Supercluster, the Milky Way's home. The flows of galaxies throughout Laniakea converge near the Norma and Centaurus clusters, close to the position of the Great Attractor.

An open question

Astronomers still debate how much of the Local Group's motion the Great Attractor causes. The 2026 measurement supports the idea that it causes most of it. A 2026 study using computer models of the nearby universe found the opposite: no single structure, including the Great Attractor, is likely to account for most of the motion. More distant structures, such as the Shapley Supercluster, also pull on the Milky Way.

Sources

La Escala del Universo > Distance to the Great Attractor

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