Which galaxies are closest to milky way

This stellar formation is about 42, light years from the galactic center , and a mere 25, light years from our Solar System. This puts it closer to us than the center of our own galaxy, which is 30, light years away from the Solar System.

The Canis Major Dwarf Galaxy Dwarf Galaxy is believed to contain one billion stars in all, a relatively high-percentage of which are in the Red Giant Branch phase of their lifetimes. It has a roughly elliptical shape and is thought to contain as many stars as the Sagittarius Dwarf Elliptical Galaxy , the previous contender for closest galaxy to our location in the Milky Way. In addition to the dwarf galaxy itself, a long filament of stars is visible trailing behind it.

This complex, ringlike structure — which is sometimes referred to as the Monoceros Ring — wraps around the galaxy three times. It was in the course of investigating this ring of stars, and a closely spaced group of globular clusters similar to those associated with the Sagittarius Dwarf Elliptical Galaxy, that the Canis Major Dwarf Galaxy was first discovered. The current theory is that this galaxy was accreted or swallowed up by the Milky Way Galaxy. Other globular clusters that orbit the center of our Milky Way as a satellite — i.

Prior to its discovery, astronomers believed that the Sagittarius Dwarf Galaxy was the closest galactic formation to our own. At 70, light years from Earth, this galaxy was determined in to be closer to us than the Large Magellanic Cloud LMC , the irregular dwarf galaxy that is located , light years from Earth, and which previously held the title of the closest galaxy to the Milky Way.

This collaborative astronomical mission, which took place between and , relied on data obtained by the Mt. Infrared astronomy takes advantage of advances in astronomy that see more of the Universe, since infrared light is not blocked by gas and dust to the same extent as visible light. Because of this technique, the astronomers were able to detect a very significant over-density of class M giant stars in a part of the sky occupied by the Canis Major constellation, along with several other related structures composed of this type of star, two of which form broad, faint arcs as seen in the image close to the top.

Dwarf irregular galaxies in the Local Group can have just a few thousand stars, which makes them downright pint-sized compared with the Milky Way and its hundreds of billions of stars. Even so, astronomers are keen to better understand these featherweights of the cosmos. The largest and best-known dwarf irregular galaxies in the Local Group are the Large and Small Magellanic Clouds, which look like fuzzy patches in the Southern Hemisphere night sky.

The Magellanic Clouds feature prominently in myths: Aboriginal people in Australia tell stories of the Magellanic Clouds alternatively as a man and a woman, hunters, or the ashes of rainbow lorikeets birds.

The Large and Small Magellanic Clouds lie some , and , light-years away, respectively, distances slightly greater than the diameter of the Milky Way.

Given their relative proximity, each Magellanic Cloud holds the distinction of being one of a smattering of galaxies in which scientists can resolve individual stars.

Hubble Space Telescope images have revealed that the Large Magellanic Cloud is forming stars in dense groups that may be the precursors to globular clusters. These intense star formation sites allow a better understanding of high-mass-star formation, a process common in galaxies that are much farther away than the Local Group.

Fox and his colleagues have shown that the Milky Way is stripping away the gas of the two dwarf galaxies and collecting it in a massive cloud known as the Magellanic Stream. Because gas is necessary to form stars, the Milky Way is collecting star-forming material and depriving the Magellanic Clouds of their stellar fuel.

Stars are factories for making metals, which astronomers consider to be any element heavier than helium. Some of the metals that stars produce become part of the nebulae from which later generations of stars are born. Therefore, the prevalence of metals in a galaxy — its metallicity — increases over time, at least for galaxies that are actively forming stars. Larger galaxies contain a higher fraction of metals, on average, than smaller ones. The dwarf irregular galaxies in the Local Group have metallicities that are much lower.

Researchers discovered one such chemically pristine galaxy in the Local Group using data collected by the Sloan Extension for Galactic Understanding and Exploration SEGUE , a comprehensive survey of the sky conducted between and Astronomers combed through SEGUE data to search for stars that had both similar positions and velocities, hoping to find new galaxies that were much too small and faint to see with current telescopes.

Segue 2 is peculiar in another respect: its mass or lack thereof. Most galaxies contain copious amounts of dark matter, a mysterious substance that interacts gravitationally with other matter but does not emit, reflect, or scatter light.

Typical galaxies like the Milky Way have 10 times as much dark matter as normal matter. Less massive dwarf galaxies have relatively more dark matter, up to 1, times as much as normal matter. When Kirby and his team first looked at Segue 2, they expected it to also have lots of dark matter. They studied how its stars moved using the Keck II Telescope in Hawaii and inferred that the ratio of dark matter to normal matter in Segue 2 was at most to 1 — far less than predicted.

The observations revealed that the total mass of Segue 2 — including dark matter — was a puny , times that of the Sun. And it might not be alone. Astronomers suspect that the Local Group could harbor far more galaxies than the roughly 85 that are currently known. Searches are underway to find such dark- matter-dominated galaxies, and earlier this year a team of astronomers led by Sukanya Chakrabarti at the Rochester Institute of Technology announced four stars possibly belonging to a Local Group galaxy consisting mostly of dark matter.

The Andromeda Galaxy, some 2. In fact, M31 shows evidence for even more interactions with its cadre of gravitational groupies than the Milky Way. Earlier this year, astronomers at the University of Notre Dame and the Uni-versity of Wisconsin-Madison published the discovery of a massive halo of gas around M The halo, which they discovered using Hubble, extends halfway to the Milky Way and contains metals such as carbon, oxygen, and silicon, some of which may have been stripped from satellite galaxies that merged with Andromeda.

When the Milky Way and Andromeda do finally collide, the supermassive black hole at the center of each galaxy will orbit around each other, releasing copious amounts of energy. Supermassive black holes are relatively rare in the Local Group, however: Out of the roughly 85 galaxies, only three — the Milky Way, Andromeda, and a dwarf elliptical satellite of Andromeda known as M32 — show evidence for such a monster.

Cosmic cannibalism appears to be ubiquitous around large galaxies in the Local Group. Even so, some galaxies seem. It orbits Andromeda yet possesses no central bulge of stars, which is often a telltale sign of previous galactic mergers. Theoretical models also suggest that in the early universe, vast tendrils of dark matter provided normal matter the gravitational scaffold it needed to coalesce into the first galaxies.

But there are still open questions about how galaxies form. Some believe that galaxies formed from smaller clusters of about one million stars, known as globular clusters , while others hold that galaxies formed first, and later birthed globular clusters. It's also difficult to figure out how many of a given galaxy's stars formed in situ from its own gas , versus forming in another galaxy and joining the party later. By letting astronomers peer into the universe's farthest reaches—and earliest moments—instruments such as NASA's James Webb Space Telescope should help resolve lingering questions.

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