Scientists are studying the history of collisions between the Milky Way and other galaxies and the possible consequences of future collisions. These collisions, incidentally, are still occurring
The Milky Way’s halo contains a large group of stars with unusual orbits, many of which are believed to have been engulfed by our galaxy during an event astronomers call the “last major merger.” As the name suggests, this was the last time our galaxy experienced a significant collision with another galaxy—presumably a massive dwarf galaxy that flooded the Milky Way with stars passing very close to our galaxy’s center.
Magnetars are neutron stars with the strongest magnetic fields. What is known about them today?
Magnetars are a special class of neutron stars with ultra-strong magnetic fields, the strongest of any object in the observable universe, approximately a trillion times stronger than the most powerful permanent magnets ever created on Earth. Neutron stars are the remnant cores of massive stars formed at the end of their lives, possessing a mass greater than the Sun and compressed to the size of a city, making them natural laboratories for studying extreme physical phenomena. Magnetars, as previously thought, can come in different types. One possibility is an exploding object orbiting a black hole surrounded by a disk of material. Another possibility is a pair of rotating neutron stars whose magnetospheres periodically interact, creating a cavity where eruptions can occur. Magnetars are estimated to be active for about 10,000 years before settling down, so they could be found where a firestorm of star formation is occurring. However, this does not seem to be the case for all magnetars.
Modern technologies and problems of studying the Milky Way
The European Space Agency’s XMM-Newton and NASA’s Chandra space telescopes captured the aftermath of three bright explosions echoing in the Milky Way’s outer spiral arms. NASA’s Nancy Grace Roman Space Telescope will help scientists better understand the fainter components of our Milky Way galaxy—the gas and dust scattered between stars, known as the interstellar medium. Scientists can also gain insight into the ages, masses, and sizes of stars using the Kepler space telescope, which provided asteroseismic data on approximately 16,000 stars before its decommissioning in 2018. A laser star pointer mounted on Cerro Pachón in central Chile points upward across the Gemini South observatory’s field of view, illuminating the Milky Way.
In 2024-2026, a theory of dark matter accumulation in the center of our Galaxy was developed
New models show that stars can exist using only dark matter as fuel, and because there is an extremely large amount of dark matter near the Galactic Center, these stars become immortal.
New discoveries in the field of interactions in stellar systems
Using the Transiting Exoplanet Survey Satellite (TESS), a spacecraft designed to search for exoplanets, astronomers discovered an unusual quadruple star system. During another dedicated observing campaign, XRISM revealed that hot plasma signals follow the orbital motion of an otherwise invisible companion star. And a new study by Japanese scientists has shown that our Sun and numerous similar “solar twins” may have migrated together from the core of the Milky Way galaxy.
The search for dark matter in our Milky Way galaxy is the most challenging task in modern physics
Stars have been observed crawling along the outskirts of the Milky Way more slowly than expected—a slow motion that scientists say can only be explained if our map of galaxies containing dark matter is incorrect. The specific velocities of stars at the edges of these galaxies have historically been irrefutable evidence of the presence of dark matter in galaxies. This is because astronomers can measure a galaxy’s “rotation curve,” which plots the orbital velocities of stars against their distance from the galactic center.
Several black holes have been discovered in our Milky Way galaxy. At the galaxy’s heart is a dormant one 4.2 million times larger than the Sun
The black holes at the center of the Milky Way (Earth’s home galaxy) and Andromeda (one of our closest galactic neighbors) are among the quietest eaters in the universe. What little light they emit varies subtly in brightness, suggesting that they consume a small but steady stream of matter rather than large clumps. The streams approach the black hole gradually and in a spiral, like water swirling down a drain.