The Inner and Outer Milky Way Aren’t the Same Thickness, and that’s Surprising

Illustration depicting the Smith Cloud on its journey to the Milky Way Creator: NRAO/AUI/NSF Credit: B. Saxton, NRAO/AUI/NSF

At first glance, the universe and night sky seem largely unchanging. The reality is very different, even now, a gas cloud is charging toward the Milky Way Galaxy and is expected to crash into us in 27 million years. A team of astronomers hoping to locate the exact position of the expected impact site have been unsuccessful but have accidentally measured the thickness of the Milky Way! Analysing radio data, they have been able to deduce the thickness of the inner and outer regions and discovered a dramatic difference between the two. 

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Hot Gas is Being Vented Away from the Center of the Milky Way

X-Ray Data Revealing Jets at the Center of the Milky Way Credit: X-ray: NASA/CXC/Univ. of Chicago/S.C. Mackey et al.; Radio: NRF/SARAO/MeerKAT; Image Processing: NASA/CXC/SAO/N. Wolk

Studying gas in the Universe is no easy task. We often look to ‘non-visible’ wavelengths of the electromagnetic spectrum such as X-rays. The Chandra X-Ray observatory has been observing a vent of hot gas blowing away from the centre of the Milky Way. Located about 26,000 light years away, the jet extends for hundreds of light years and is perpendicular to the disk of the Galaxy. It is now thought the gas has been forced away from the centre of the Milky Way because of a collision with cooler gas lying in its path and creating shockwaves. 

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Three of the Oldest Stars in the Universe Found Circling the Milky Way

MIT astronomers discovered three of the oldest stars in the universe, and they live in our own galactic neighborhood. The stars are in the Milky Way’s “halo” — the cloud of stars that envelopes the main galactic disk — and they appear to have formed between 12 and 13 billion years ago, when the very first galaxies were taking shape. Credits:Image: Serge Brunier; NASA

Mention the Milky Way and most people will visualise a great big spiral galaxy billions of years old. It’s thought to be a galaxy that took shape billions of years after the Big Bang. Studies by astronomers have revealed that there are the echo’s of an earlier time around us. A team of astronomers from MIT have found three ancient stars orbiting the Milky Way’s halo. The team think these stars formed when the Universe was around a billion years old and that they were once part of a smaller galaxy that was consumed by the Milky Way. 

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Does the Milky Way Have Too Many Satellite Galaxies?

Large Magellanic Cloud. Credit: ESA

The Large and Small Magellanic Clouds are well known satellite galaxies of the Milky Way but there are more. It is surrounded by at least 61 within 1.4 million light years (for context the Andromeda Galaxy is 2.5 million light years away) but there are likely to be more. A team of astronomers have been hunting for more companions using the Subaru telescope and so far, have searched just 3% of the sky. To everyone’s surprise they have found nine previously undiscovered satellite galaxies, far more than expected. 

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Black Holes Can Halt Star Formation in Massive Galaxies

This research published in Nature is the first direct confirmation that supermassive black holes are capable of shutting down galaxies

It’s difficult to actually visualise a universe that is changing. Things tend to happen at snails pace albeit with the odd exception. Take the formation of galaxies growing in the early universe. Their immense gravitational field would suck in dust and gas from the local vicinity creating vast collections of stars. In the very centre of these young galaxies, supermassive blackholes would reside turning the galaxy into powerful quasars. A recent survey by the James Webb Space Telescope (JWST) reveals that black holes can create a powerful solar wind that can remove gas from galaxies faster than they can form into stars, shutting off the creation of new stars.

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Mapping the Milky Way’s Magnetic Field in 3D

The Milky Way's magnetic field

We are all very familiar with the concept of the Earth’s magnetic field. It turns out that most objects in space have magnetic fields but it’s quite tricky to measure them. Astronomers have developed an ingenious way to measure the magnetic field of the Milky Way using polarised light from interstellar dust grains that align themselves to the magnetic field lines. A new survey has begun this mapping process and has mapped an area that covers the equivalent of 15 times the full Moon. 

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The Milky Way’s Most Massive Stellar Black Hole is Only 2,000 Light Years Away

This image shows the locations of the first three black holes discovered by ESA's Gaia mission in the Milky Way. Gaia Black Hole 1 (BH1) is located just 1560 light-years away from us in the direction of the constellation Ophiuchus; Gaia BH2 is 3800 light-years away in the constellation Centaurus; Gaia BH3 is in the constellation Aquila, at a distance of 1926 light-years from Earth. In galactic terms, these black holes reside in our cosmic backyard. Image Credit: ESA/Gaia/DPAC. Licence CC BY-SA 3.0 IGO

Astronomers have found the largest stellar mass black hole in the Milky Way so far. At 33 solar masses, it dwarfs the previous record-holder, Cygnus X-1, which has only 21 solar masses. Most stellar mass black holes have about 10 solar masses, making the new one—Gaia BH3—a true giant.

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The Milky Way’s Role in Ancient Egyptian Mythology

the sky goddess Nut, covered in stars, is held aloft by her father, Shu, and is arched over Geb, her brother the Earth god. On the left, the rising sun (the falcon-headed god Re) sails up Nut’s legs. On the right, the setting sun sails down her arms towards the outstretched arms of Osiris, who will regenerate the sun in the netherworld during the night.

Look through the names and origins of the constellations and you will soon realise that many cultures had a hand in their conceptualisation. Among them are the Egyptians who were fantastic astronomers. The movement of the sky played a vital role in ancient Egypt including the development of the 365 day year and the 24 hour day. Like many other cultures they say the Sun, Moon and planets as gods. Surprisingly though, the bright Milky Way seems not to have played a vital role. Some new research suggests that this may not be the case and it may have been a manifestation of the sky goddess Nut! 

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Roman Will Learn the Ages of Hundreds of Thousands of Stars

By carefully observing star spots, the Nancy Grace Roman Space Telescope will determine stellar ages. It needs some help from AI though. Image Credit: NASA and STScI

Astronomers routinely provide the ages of the stars they study. But the methods of measuring ages aren’t 100% accurate. Measuring the ages of distant stars is a difficult task.

The Nancy Grace Roman Space Telescope should make some progress.

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The Large Magellanic Cloud isn’t Very Metal

This image shows the Large and Small Magellanic Clouds in the sky over the ESO's Paranal Observatory and the four telescopes of the VLT. Image Credit: By ESO/J. Colosimo -, CC BY 4.0,

The Large Magellanic Cloud (LMC) is the Milky Way’s most massive satellite galaxy. Because it’s so easily observed, astronomers have studied it intently. They’re interested in how star formation in the LMC might have been different than in the Milky Way.

A team of researchers zeroed in on the LMC’s most metal-deficient stars to find out how different.

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