Despite everything astronomers have learned about the nature and structure of galaxies, there are still mysteries about the Milky Way. The reason for this is simple: since we are embedded in the Milky Way’s disk, we have difficulty mapping it and observing it as a whole. It’s also very challenging to observe the center of the galaxy, what lies beyond it, and features in the disk itself because of all the gas and dust between stars- the Interstellar Medium (ISM). However, by observing the Milky Way in the non-visible spectrum (radio, x-ray, gamma-ray, etc.), astronomers can see more of what’s out there.
There’s also the spectral line that corresponds to the emission frequency (1420 MHz) of cold neutral hydrogen gas (HI), which makes up the majority of the ISM. Using the Five-hundred-meter Aperture Spherical Telescope (FAST) – the most powerful radio telescope in the world near Guizhou, China – a team of scientists located more than 500 new faint pulsars. During the survey, the team simultaneously recorded the spectral line data with high spectral and spatial resolution, making it an extremely valuable resource for studying the structure of the Milky Way Galaxy and the life cycle of its stars.
For decades, astronomers have advocated building radio telescopes on the far side of the Moon. This “radio-quiet” zone always faces away from Earth and would provide the perfect location to study a variety of astronomical phenomena that can’t be observed in low radio frequencies from our planet, or even by Earth-orbiting space telescopes. But the costs and logistics of such a project have pushed most of these concepts to the realm of futuristic dreams.
But now a group of astronomers and engineers have worked out a concept for a radio telescope placed on the lunar far side that could be as large as 100 square kilometers across, and it could be deployed from a robotic lunar lander and four two-wheeled rovers.
Interstellar winds are powerful agents of change. For one thing, they can interrupt or shut down the process of star birth completely. That’s what a team of astronomers using the Karl Jansky Very Large Array in New Mexico found when they studied the galaxy M33. They also learned that speedy cosmic rays play a huge role in pushing those winds across interstellar space.
Originally predicted by Einstein’s Theory of General Relativity, black holes are the most extreme object in the known Universe. These objects form when stars reach the end of their life cycle, blow off their outer layers, and are so gravitationally powerful that nothing (not even light) can escape their surfaces. They are also of interest because they allow astronomers to observe the laws of physics under the most extreme conditions. Periodically, these gravitational behemoths will devoir stars and other objects in their vicinity, releasing tremendous amounts of light and radiation.
In October 2018, astronomers witnessed one such event when observing a black hole in a galaxy located 665 million light-years from Earth. While astronomers have witnessed events like this before, another team from the Harvard & Smithsonian Center for Astrophysics noticed something unprecedented when they examined the same black hole three years later. As they explained in a recent study, the black hole was shining very brightly because it was ejecting (or “burping”) leftover material from the star at half the speed of light. Their findings could provide new clues about how black holes feed and grow over time.
Radio astronomy has been in flux lately. With the permanent loss of the Arecibo telescope in Puerto Rico, a new global power has taken center stage in humanity’s search for radio signals – China. Recently the Chinese announced the start of work on a new milestone telescope, which will eventually make it the biggest moveable one in the world.
Do aliens exist? Almost certainly. The universe is vast and ancient, and our corner of it is not particularly special. If life emerged here, it probably did elsewhere. Keep in mind this is a super broad assumption. A single instance of fossilized archaebacteria-like organisms five superclusters away would be all it takes to say, “Yes, there are aliens!” …if we could find them somehow.
Well, this is the week for distant galaxies, isn’t it? Not only has JWST revealed some of the most distant ones ever seen in infrared, but other observatories are studying them, too. Astronomers at the Cosmic Dawn Center in Copenhagen recently discovered several interesting ones in the early Universe. However, they had to get through clouds of dust to do it. Their observations revealed several interesting characteristics of objects that existed when the Universe was only a tenth of its current age.
Neutron stars are dense remnants of large stars. They are the collapsed cores of stars formed during a supernova explosion. While we know generally how they form, we are still learning how they evolve, particularly when they are young. But that’s starting to change thanks to large sky surveys, which have allowed astronomers to observe a neutron star that could be little more than a decade old.
The best way to do this is to observe the structure of the Universe on the largest of scales, where astronomers can observe the distribution of galaxies, the nature of gravity, and the role of dark matter and dark energy. To this end, an international team of astronomers has combined the power of MeetKAT’s 64 radio telescopes to detect faint signatures of neutral hydrogen gas across cosmological scales. The resulting accuracy and sensitivity provide a demonstration of what the SKAO will be able to achieve in the near future.
Astronomy is progressing rapidly these days, thanks in part to how advances in one area can contribute to progress in another. For instance, improved optics, instruments, and data processing methods have allowed astronomers to push the boundaries of optical and infrared to gravitational wave (GW) astronomy. Radio astronomy is also advancing considerably thanks to arrays like the MeerKAT radio telescope in South Africa, which will join with observatories in Australia in the near future to create the Square Kilometer Array (SKA).
In particular, radio astronomers are using next-generation instruments to study phenomena like Fast Radio Bursts (FRBs) and neutron stars. Recently, an international team of scientists led by the University of Manchester discovered a strange radio-emitting neutron star with a powerful magnetic field (a “magnetar”) and an extremely slow rotational period of 76 seconds. This discovery could have significant implications for radio astronomy and hints at a possible connection between different types of neutron stars and FRBs.