Mastodawn

This is potentially excellent news for ESA's Comet Interceptor mission, due to launch later this decade.

It adds further weight to the idea that these interstellar interlopers may be quite common, raising the chances that Comet Interceptor will be able to target a flyby past one from its Sun-Earth L2 loiter orbit.

And with the Rubin Observatory now online, surveying the whole southern sky every three nights, many more such objects may soon be discovered.

Demallien 15h ago

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Mark McCaughrean 1d ago

3I/ATLAS is thought be around 20km in size, so considerably larger than either of the previous interstellar objects.

It's currently out near the orbit of Jupiter, but there have been reports of some faint comet-like activity – that should become more apparent in the weeks months to come.

Demallien 15h ago

Mark McCaughrean 1d ago

Welcome to the neighbourhood, 3I/ATLAS, if only briefly 😬✌️

A new interstellar object has been found skimming through our solar system, only the third after 1I/'Oumumua & 2I/Borisov ☄️

This new object, detected by the ATLAS telescope in Chile, will make its closest approach to the Sun in late October, inside the orbit of Mars, & then barrel out again at more than 200,000 kmh 👀

More at: https://www.esa.int/ESA_Multimedia/Images/2025/07/ESA_observes_interstellar_comet_3I_ATLAS

#SpaceScience

Image credit: NASA/JPL-Caltech

Demallien 23h ago

Sophia Gad-Nasr 1d ago

Nearly every massive galaxy harbors a supermassive black hole (like Interstellar's Gargantua), but how do they form so early? One neat method is direct collapse, where gas skips the star phase and collapses right into a black hole. This only happens in the early universe when gas is pristine and a particular UV radiation permeates. The UV along with gas having no heavy elements prevents cooling and breaking apart, allowing gas clouds to collapse right into black holes the mass of ~100,000 suns.

Demallien 1d ago

Zack Whittaker 2d ago

I am once again asking companies to not be absolute shitbags about their data breach disclosures, such as deliberately blocking search engines from seeing the page by using a "noindex" tag in its HTML.

Today's edition: Australian airline Qantas.

My story: https://techcrunch.com/2025/07/02/qantas-hack-results-in-theft-of-6-million-passengers-personal-data/

Demallien 2d ago

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ESO 2d ago

The observations support the idea that SNR 0509-67.5 was generated by a white dwarf, which formed a blanket of helium stolen from a companion star. This helium became unstable and ignited, sending a shockwave around the white dwarf and inwards. The explosion triggered a second detonation in the core of the star, ultimately creating the supernova.

The fingerprint left by this process? Two separate shells of calcium found in the supernova’s remains.

Demallien 2d ago

ESO 2d ago

💥💥 Double detonation!

For the first time, astronomers have obtained visual evidence that a star met its end by blasting twice.

This was done by studying the centuries-old remains of supernova SNR 0509-67.5 with our Very Large Telescope. Led by the Univ. of South Wales, this shows some of the most important explosions in the Universe in a new light.

What happened exactly? Keep reading.

#astrodon #astronomy #astrophysics #space #science

📷 ESO/P. Das et al. Backgr. stars (HST): K. Noll et al.

Demallien 2d ago

Lauren Weinstein 2d ago

BTW, when the Big Tech bros wax poetic about eliminating passwords by requiring passkeys, you can bet they probably don't deal with anyone who doesn't have a phone and whose only access to the Internet is public computers like in libraries. And please don't suggest that someone who may have all their possessions in a shopping cart carry and use a Yubikey (even if USB ports weren't blocked on public computers, as they often are). The Bros often don't have a clue about the real world.

Demallien 2d ago

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Sophia Gad-Nasr 2d ago

The above is a composite image taken with JWST's NIRCam, so using near-infrared light. Here, you can see the core of the galaxy in mid-infrared, which reveals more of the emission from the dust clouds and barely any stars. It's pretty amazing how different wavelengths of light can show a completely different view of a galaxy.