Lifeboat Foundation: Safeguarding Humanity
Toggle light / dark theme

Blog

Category: cosmology – Page 147

This image of galaxy cluster MACS J1206.2–0847 (or MACS 1,206 for short) is part of a broad survey with NASA’s Hubble Space Telescope.

The distorted shapes in the cluster are distant galaxies from which the light is bent by the gravitational pull of an invisible material called dark matter within the cluster of galaxies. This cluster is an early target in a survey that will allow astronomers to construct the most detailed dark matter maps of more galaxy clusters than ever before.

These maps are being used to test previous, but surprising, results that suggest that dark matter is more densely packed inside clusters than some models predict. This might mean that galaxy cluster assembly began earlier than commonly thought.

Read more | >

Researchers discovered only relatively recently that black hole jets emit X-rays, and how the jets accelerate particles to this high-energy state is still a mystery. Surprising new findings in Nature Astronomy appear to rule out one leading theory, opening the door to reimagining how particle acceleration works in the jets—and possibly also elsewhere in the universe.

One leading model of how jets generate X-rays expects the jets’ X-ray emissions to remain stable over long time scales (millions of years). However, the new paper found that the X-ray emissions of a statistically significant number of jets varied over just a few years.

“One of the reasons we’re excited about the variability is that there are two main models for how X-rays are produced in these jets, and they’re completely different,” explains lead author Eileen Meyer, an astronomer at University of Maryland, Baltimore County. “One model invokes very low-energy electrons and one has very high-energy electrons. And one of those models is completely incompatible with any kind of variability.”

Read more | >

The Gemini North telescope, one half of the International Gemini Observatory operated by NSF’s NOIRLab, has returned from a seven-month hiatus literally with a bang, as it has captured the spectacular aftermath of a supernova, a massive star that exploded in the large, face-on, spiral Pinwheel Galaxy (Messier 101). The supernova, named SN 2023ixf (lower left), was discovered on May 19 by amateur astronomer Koichi Itagaki.

Since its discovery, observers around the globe have pointed their telescopes toward Messier 101 to get a look at the burst of light. Over the coming months, Gemini North will allow astronomers to study how the light from the fades and how its spectrum evolves over time, helping astronomers better understand the physics of such explosions.

The appearance of SN 2023ixf is rather serendipitous for the Gemini North telescope, which is back to observing with its primary mirror repaired and recoated after suffering damage in late 2022. The damage was limited to a small region outside of the light-collecting area of the mirror. Nevertheless, the repairs were carefully planned and completed to ensure that Gemini North could safely return to normal operations. This process lasted approximately seven months and in May 2023 the mirror was recoated and reinstalled, and the control systems were powered up and tested.

Read more | >

The Big Bang, traditionally considered the birth of the universe about 14 billion years ago, is being questioned. Physicist Bruno Bento and his team have proposed compelling research suggesting the universe may have always existed, and the Big Bang may merely be a significant event in its continuous evolution.

Bruno Bento and his colleagues set out to examine what the universe’s inception might have looked like without a Big Bang singularity. They grappled with contradictions arising when comparing accepted theories, particularly those dealing with quantum physics and general relativity. While quantum physics has accurately described three of the four fundamental forces of nature, it struggles to incorporate gravity. On the other hand, general relativity offers a comprehensive explanation of gravity, but falters when dealing with black holes’ centers and the universe’s genesis.

These contentious areas, termed “singularities,” are points in space-time where established physical laws cease to apply. Intriguingly, computations indicate an immense gravitational pull within singularities, even on a minuscule scale.

Read more | >

A groundbreaking revelation has the scientific community buzzing: a possible encounter with a parallel universe. Researchers suggest that signs from the universe’s furthest reaches may indicate another vastly different universe has touched ours, potentially disrupting our universe’s fabric. This interpretation could validate the multiverse theory.

Researcher Dr. Ranga-Ram Chary examined the cosmic microwave background’s noise and residual signals — the remnants of the Big Bang. He discovered several sporadic bright spots, which he speculates could be the echo of our universe colliding with another billions of years ago.

This interpretation is tentative, but aligns with some cosmological theories suggesting that interactions between alternative universes could occur. These theories propose our universe is merely one bubble among countless others. Once a universe initiates in a Big Bang-like event, it perpetually expands. This rule applies to all universes, implying periodic intersections could occur.

Original paper is at https://arxiv.org/pdf/1809.09615.pdf

Read more | >

Euclid is ESA’s mission to shed light on dark matter and dark energy, but teams at the Agency’s mission control centre in Darmstadt, Germany, are also in the dark. A series of problems have befallen the mission in pre-launch simulations.

Currently about halfway through the Euclid simulations campaign, the key focus in the Main Control Room is the Launch and Early Orbit Phase (LEOP) and spacecraft commissioning.

These are the two most critical moments in a mission’s life; as it wakes up after the rigours of launch, makes its first manoeuvres towards its target destination and as its instruments are commissioned.

Read more | >

Even space and time if it’s quantum.

What will be the ultimate fate of our universe? There are a number of theories and possibilities, but at present the most likely scenario seems to be that the universe will continue to expand, most mass will eventually find its way into a black hole, and those black holes will slowly evaporate into Hawking Radiation, resulting in what is called the “heat death” of the universe. Don’t worry, this will likely take 1.7×10106 years, so we got some time.

But what about objects, like stellar remnants, that are not black holes? Will the ultimate fate of the universe still contain some neutron stars and cold white dwarfs that managed to never get sucked up by a black hole? To answer this question we have to back up a bit and talk about Hawking Radiation.

Stephen Hawking famously proposed this idea in 1975 – he was asked if black holes have a temperature, and that sent him down another type of hole until Hawking Radiation popped out as the answer. But what is Hawking Radiation? The conventional answer is that the vacuum of space isn’t really nothing, it still contains the quantum fields that make up spacetime. Those quantum field do not have to have zero energy, and so occasionally virtual particles will pop into existence, always in pairs with opposite properties (like opposite charge and spin), and then they join back together, cancelling each other out. But at the event horizon of black holes, the distance at which light can just barely escape the black hole’s gravity, a virtual pair might occur where one particle gets sucked into the black hole and the other escapes. The escaping particle is Hawking Radiation. It carries away a little mass from the black hole, causing it to glow slightly and evaporate very slowly.

Continue reading “Everything Will Evaporate” | >

An international team of astrophysicists has discovered hundreds of mysterious structures in the centre of the Milky Way.

The one-dimensional cosmic threads are made up of hundreds of horizontal or radial filaments, slender, elongated bodies of luminous gas that potentially originated a few million years ago — and seem to be pointing the direction of the black hole.

“I was actually stunned when I saw these. We had to do a lot of work to establish that we weren’t fooling ourselves,” added Yusef-Zadeh, who’s also a member of the Center for Interdisciplinary Exploration and Research in Astrophysics.

Read more | >