Lifeboat Foundation

Dark matter is the invisible force holding the universe together—or so we think. It makes up about 85% of all matter and around 27% of the universe’s contents, but since we can’t see it directly, we have to study its gravitational effects on galaxies and other cosmic structures. Despite decades of research, the true nature of dark matter remains one of science’s most elusive questions.

Proposed experiments will search for signs that spacetime is quantum and can exist in a superposition of multiple shapes at once.

By Nick Huggett & Carlo Rovelli

There is a glaring gap in our knowledge of the physical world: none of our well-­established theories describe gravity’s quantum nature. Yet physicists expect that this quantum nature is essential for explaining extreme situations such as the very early universe and the deep interior of black holes. The need to understand it is called the problem of “quantum gravity.”

“Both galaxies in the Question Mark Pair show active star formation in several compact regions, likely a result of gas from the two galaxies colliding,” said Dr. Vicente Estrada-Carpenter.

How did stars form 7 billion years ago, or approximately halfway between the Big Bang and now? This is what a recent study published in the Monthly Notices of the Royal Astronomical Society hopes to address as an international team of researchers used NASA’s James Webb Space Telescope (JWST) to observe two distant galaxies using the gravitational lensing method, which is a “magnifying glass” that forms around large celestial objects that warp the fabric of space-time. This study holds the potential to help astronomers better understand the conditions in the early universe and the techniques used to study those conditions.

While the gravitational lensing method enables observations of distant objects, those objects also tend to appear distorted due to the space-time warping. In this case, the distant galaxies being observed appear together as a question mark in the JWST images, though astronomers were still able to learn quite a bit about this galaxy. These findings included new insights into star formation, with several stars in the red galaxy exhibiting various stages of formation, including bursty stars, quenching stars, and stars in equilibrium.

Continue reading “Galaxy Interactions and Cosmic Illusions: Webb’s Stunning New Images” »

In a continuous pursuit to understand the fundamental laws that govern the universe, researchers have ventured deep into the realms of string theory, loop quantum gravity, and quantum geometry. These advanced theoretical frameworks have revealed an especially compelling concept: the generalized uncertainty principle (GUP).

A recent study underscores the dynamic nature of black holes and extends similar thermodynamic characteristics to Extremely Compact Objects, advancing our comprehension of their behavior in quantum gravity scenarios.

A paper titled “Universality of the thermodynamics of a quantum-mechanically radiating black hole departing from thermality,” published in Physics Letters B highlights the importance of considering black holes as dynamical systems, where variations in their geometry during radiation emissions are critical to accurately describing their thermodynamic behavior.

Bridging black holes and extremely compact objects.

In the study, an international team of astronomers identified three supermassive black holes lurking near the center of galaxy NGC 6,240, which has been visibly disturbed by the gravitational effects of a triple merger. Because NGC 6,240 is so close—just 300 million light-years away—astronomers had previously assumed that its odd shape was the product of a typical merger between two galaxies. They believed that these two galaxies collided as they increased to hundreds of miles per second, and that they are still combining. Therefore, the researchers expected to find two supermassive black holes hiding near the center of the cosmic collision.

Instead, the team discovered three supermassive black holes, each weighing more than 90 million Suns, when they used 3D mapping techniques to peer into the core of NGC 6240. (To put this into perspective, Sagittarius A*, the supermassive black hole at the center of the Milky Way, is roughly 4 million solar masses in weight.) Furthermore, the three massive black holes of NGC 6,240 are confined to an area that is less than 3,000 light-years across, or less than 1% of the galaxy in which they are found.

“Up until now, such a concentration of three supermassive black holes had never been discovered in the universe,” said study co-author Peter Weilbacher of the Leibniz Institute for Astrophysics Potsdam in a press release. This is the first time that scientists have seen a group of supermassive black holes packed into such a small area, despite the fact that they have previously discovered three distinct galaxies and the black holes that are connected to them on a collision course.

The Standard Model of particle physics is currently our best understanding of how the universe works – but it only describes about five percent of everything in it. The rest is made up of what we call dark matter and dark energy, which are so far only known through their gravitational interactions with regular matter. Now, an astrophysicist from Oxford has put forward a new theory that suggests that dark matter and dark energy are actually part of the same phenomenon: a “dark fluid” with negative mass that fills the universe.

In a way, dark matter and dark energy are both placeholder concepts, plugging holes between the Standard Model and what we actually observe. For instance, the observed movement and distribution of galaxies doesn’t make sense if their mass is limited to the stuff we can see. Since the 1930s, this hidden extra mass has been dubbed dark matter.

Dark energy is a more recent concept. The observation that the expansion of the universe seems to be accelerating was only made in 1998, when it was discovered that more distant objects are moving away from us faster than those closer by. The mysterious force that drives this, which we still know very little about, is now referred to as dark energy.

A hypothesis by Justin Khoury of the Department of Physics and Astronomy stands to shake up how scientists consider dark matter.

These models are very, very wrong.