Universe Today

February 6, 2024February 6, 2024 by Brian Koberlein

Astronomers Measure the Mass of the Milky Way by Calculating How Hard it is to Escape

Artist view of the Milky Way galaxy. Credit: ESA

If you want to determine your mass, it’s pretty easy. Just step on a scale and look at the number it gives you. That number tells you the gravitational pull of Earth upon you, so if you feel the number is too high, take comfort that Earth just finds you more attractive than others. The same scale could also be used to measure the mass of Earth. If you place a kilogram mass on the scale, the weight it gives is also the weight of Earth in the gravitational field of the kilogram. With a bit of mass, you have the mass of Earth.

February 5, 2024February 8, 2024 by Matt Williams

NASA’s Juno Probe Makes Another Close Flyby of Io

Processed image taken by JunoCam on Feb. 3rd, 2024, during the probe's second close flyby of Jupiter’s moon Io. Credit: NASA/SwRI/MSSS

The Juno spacecraft has revealed some fascinating things about Jupiter since it began exploring the system on July 4th, 2016. Not only is it the first robotic mission to study Jupiter up close while orbiting it since the Galileo spacecraft, which studied the gas giant and its satellites from 1995 to 2003. Juno is also the first robotic explorer to look below Jupiter’s dense clouds to investigate the planet’s magnetic field, composition, and structure. The data this has produced is helping scientists address questions about how Jupiter formed and the origins of the Solar System.

Since 2021, the probe has been in an extended mission phase, where it has been making flybys of some of Jupiter’s largest moons, including Ganymede, Europa, and Io. As it passes these satellites, Juno has captured some incredible images with its main imaging instrument, the JunoCam. On Saturday, February 3rd, 2024, the Juno spacecraft made another flyby of Io and took more captivating photos of the volcanic moon and its pockmarked surface. This was the second part of a twin flyby designed to provide new insight into Io’s volcanic nature and the interior structure of the satellite.

February 5, 2024February 5, 2024 by Carolyn Collins Petersen

NASA is One Step Closer to Deploying Fission Reactors on the Moon

An artist's concept of possible nuclear fission reactors on the Moon. Credit: NASA

What’s the most important thing you need to live and work on the Moon? Power. For NASA’s upcoming Artemis program, getting power to lunar bases is a top priority. That’s why the agency created its Fission Surface Power Project. The idea is to develop concepts for a small nuclear fission reactor to generate electricity on the lunar surface.

February 5, 2024February 5, 2024 by Evan Gough

The JWST Discovers a Galaxy That Shouldn’t Exist

The JWST captured this image of an unusual quiescent dwarf galaxy in the background of separate observations. Image Credit: Carleton et al. 2024

Astronomers working with the JWST found a dwarf galaxy they weren’t looking for. It’s about 98 million years away, has no neighbours, and was in the background of an image of other galaxies. This isolated galaxy shows a lack of star-formation activity, which is very unusual for an isolated dwarf.

Most isolated dwarf galaxies form stars, according to a wealth of observations. What’s different about this one?

February 4, 2024February 4, 2024 by Brian Koberlein

How Could Laser-Driven Lightsails Remain Stable?

Project Starshot, an initiative sponsored by the Breakthrough Foundation, is intended to be humanity's first interstellar voyage. Credit: breakthroughinitiatives.org

It’s a long way to the nearest star, which means conventional rockets won’t get us there. The fuel requirements would make our ship prohibitively heavy. So an alternative is to travel light. Literally. Rather than carrying your fuel with you, simply attach your tiny starship to a large reflective sail, and shine a powerful laser at it. The impulse of photons would push the starship to a fraction of light speed. Riding a beam of light, a lightsail mission could reach Proxima Centauri in a couple of decades. But while the idea is simple, the engineering challenges are significant, because, across decades and light-years, even the smallest problem can be difficult to solve.

February 3, 2024February 3, 2024 by Brian Koberlein

Atmospheres in the TRAPPIST-1 System Should be Long Gone

Illustration of the Trappist-1 system. Credit: NASA/JPL-Caltech

Trappist-1 is a fascinating exoplanetary system. Seven worlds orbiting a red dwarf star just 40 light-years away. All of the worlds are similar to Earth in mass and size, and 3 or 4 of them are potentially habitable. Imagine exploring a system of life-rich worlds within easy traveling distance of each other. It’s a wonderful dream, but as a new study shows it isn’t likely that life exists in the system. It’s more likely the planets are barren and stripped of their atmospheres.

February 2, 2024February 2, 2024 by Matt Williams

Astronomers are Getting Really Good at Weighing Baby Supermassive Black Holes

Illustration of an active quasar. New research shows that SMBHs eat rapidly enough to trigger them. Credit: ESO/M. Kornmesser

In the 1970s, astronomers deduced that the persistent radio source coming from the center of our galaxy was actually a supermassive black hole (SMBH). This black hole, known today as Sagittarius A*, is over 4 million solar masses and is detectable by the radiation it emits in multiple wavelengths. Since then, astronomers have found that SMBHs reside at the center of most massive galaxies, some of which are far more massive than our own! Over time, astronomers observed relationships between the properties of galaxies and the mass of their SMBHs, suggesting that the two co-evolve.

Using the GRAVITY+ instrument at the Very Large Telescope Interferometer (VLTI), a team from the Max Planck Institute for Extraterrestrial Physics (MPE) recently measured the mass of an SMBH in SDSS J092034.17+065718.0. At a distance of about 11 billion light-years from our Solar System, this galaxy existed when the Universe was just two billion years old. To their surprise, they found that the SMBH weighs in at a modest 320 million solar masses, which is significantly under-massive compared to the mass of its host galaxy. These findings could revolutionize our understanding of the relationship between galaxies and the black holes residing at their centers.

February 2, 2024February 2, 2024 by Carolyn Collins Petersen

Half the Entire Sky, Seen in X-Rays

This image show half of the X-ray sky, projected onto a circle with the center of the Milky Way on the left and the galactic plane running horizontally. Photons have been colour-coded according to their energy (red for energies 0.3-0.6 keV, green for 0.6-1 keV, blue for 1-2.3 keV). Credit: MPE, J. Sanders for the eROSITA consortium

There’s an old trope in science fiction about someone suddenly getting X-ray vision and looking through solid objects. It turns out to be a physical impossibility with our Mark I eyeballs. However, astronomers have found a way around that challenge that lets us study the Universe with X-ray vision.

February 2, 2024February 2, 2024 by Evan Gough

A Super-Earth (and Possible Earth-Sized) Exoplanet Found in the Habitable Zone

Artist depiction of the surface of a super-Earth orbiting a red dwarf. Credit: ESO/M. Kornmesser

Astronomers have found a new Super-Earth orbiting an M-dwarf (red dwarf) star about 137 light-years away. The planet is named TOI-715b, and it’s about 1.55 Earth’s radius and is inside the star’s habitable zone. There’s also another planetary candidate in the system. It’s Earth-sized, and if it’s confirmed, it will be the smallest habitable zone planet TESS has discovered so far.

February 2, 2024February 2, 2024 by Brian Koberlein

How Dangerous are Kilonovae?

An illustration of the kilonova GW170817. Credit: NASA/CXC/M.Weiss

When we look up at the sky on a particularly dark night, there is a sense of timelessness. We might see the flash of a meteor, and occasionally a comet is visible to the naked eye, but the cold and distant stars are unchanging. Or so it seems. There can also be a sense of calm, that despite all the uncertainty of the world, the stars will always watch over us. So it’s hard to imagine that light years away there could be a lurking event that poses an existential threat to humanity. That threat is extremely tiny, but not zero, and it is the focus of a recent paper published in The Astrophysical Journal.