ESA Confirms Comet 3I/ATLAS as Third Known Interstellar Visitor

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Updated Jul 3, 2025, 12:49 PM

Astronomers have confirmed the discovery of a new object that originated outside the solar system, the European Space Agency said. The International Astronomical Union’s Minor Planet Center has formally designated the body 3I/ATLAS (C/2025 N1) after it was first observed by NASA’s ATLAS survey telescope in Chile on 1 July and located retrospectively in images taken on 14 June. It is only the third interstellar object ever identified, following 1I/‘Oumuamua in 2017 and comet 2I/Borisov in 2019.

Current measurements indicate that 3I/ATLAS is a comet roughly 10–20 kilometres in diameter travelling on a hyperbolic trajectory at about 60 kilometres per second—fast enough to escape the Sun’s gravity. The object is now roughly 4.5 astronomical units from the Sun, near Jupiter’s orbit, and is expected to reach perihelion around 30 October at 1.4 AU, just inside the orbit of Mars. It will remain at least 1.6 AU (240 million kilometres) from Earth and poses no threat, according to ESA planetary-defence chief Richard Moissl.

Because the comet was detected months before its closest approach to the Sun, observatories worldwide have an unusual window to study material formed around another star. Ground-based telescopes should be able to track the object through September before it is lost in solar glare, with further observations possible once it re-emerges in December. Researchers hope spectra and brightness data gleaned during this period will shed light on the composition of extrasolar comets and refine plans for future interception missions such as ESA’s Comet Interceptor, slated for launch in 2029.

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NASA JPL

@NASAJPL

There's a new interstellar comet in the neighborhood! Known as 3I/ATLAS, this comet poses no threat to Earth – but it does provide a rare opportunity to study an object that originated outside of our solar system:

DW فارسی

@dw_persian

The European Space Agency (ESA) says it has observed a celestial mass passing through the solar system. According to the European Space Agency, there may be up to about 10,000 interstellar masses of this kind in the solar system. Scientists say the origin of this mass, probably somewhere outside the system

el Nuevo Herald

@elnuevoherald

A large interstellar object will approach Earth this fall

Black Hole

@konstructivizm

An interstellar object has been detected hurtling towards our solar system.

Le Parisien

@le_Parisien

A possible interstellar object is crossing the solar system at 60 km per second ➡️

#European Space Agency #International Astronomical Union #Minor Planet Center #NASA #ATLAS #Chile #Jupiter #Mars #Earth #ESA #Richard Moissl #Comet Interceptor

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Sources

washingtontimes.com(10)l.numerama.com(5)forbes.com(4)newscientist.com(3)

Numerama

@Numerama

Name, trajectory with respect to Earth, theory: what we know about this 3rd interstellar “visitor”

ESA auf Deutsch

@ESA_de

Astronomers may have just discovered the third interstellar object that crosses our solar system! 🌌 ESA's Planetary Defenders are currently observing the object — known as #A11pl3Z — using telescopes around the world. 🔭