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Category: cosmology – Page 78

“… living systems evolve to exploit any aspect of physics that enables exploration of all possible ‘fitness landscapes’.”

Indeed!

In 1990, within the intellectual haven of Haverford College, I embarked on a transformative academic journey into biophysics – the captivating intersection of physics and biology.

It was during this time that I delved into the tantalising notion of quantum mechanics operating within living organisms.

Unbeknownst to me, this exploration would etch an enduring imprint on my scientific voyage, kindling a lifelong fascination with biophysics. Ultimately, I charted my research course in quantum cosmology, but the echoes of biophysics persisted.

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It’s possible that our universe is the antimatter counterpart of an antimatter universe that existed earlier in time than the Big Bang. So claim physicists in Canada, who have devised a new cosmological model positing the existence of a “antiuniverse” which, paired to our own, preserves a fundamental rule of physics called CPT symmetry. Though many details in their theory still need to be worked out, the researchers claim that it naturally explains the existence of dark matter.

According to standard cosmological models, the universe—which consists of space, time, and mass/energy—exploded into being about 14 billion years ago. Since then, it has expanded and cooled, causing subatomic particles, atoms, stars, and planets to gradually form.

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Nvidia CEO Jensen Huang has unveiled plans to build a next-generation AI platform called Rubin — named after astronomer Vera Rubin.

Huang made the announcement at an address ahead of the COMPUTEX technology convention in Taipei, which starts on June 4.

According to the company’s blog, Huang spoke to nearly 6,500 industry executives, reporters, entrepreneurs, gamers, inventors, and AI fans who had congregated at the glass-domed National Taiwan University Sports Center in Taipei.

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To use the Instagram Chandra experience, search for the “NASAChandraXray” account. Select the effects options (the tab that looks like three four-pointed stars) and select the one you want. Then, you can either save the effect to your camera and apply it to your stories, or you can select the “Try it” button for instant access.

Related: Peer inside remnants of an 800-year-old supernova and see a ‘zombie’ star

“We are excited to bring data from the universe down to Earth in this way,” Kimberly Arcand, Chandra X-ray Center visualization and emerging technology scientist, said in a statement. “Enabling people to access cosmic data on their phones and through AR brings Chandra’s amazing discoveries literally right to your fingertips.”

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The Dark Energy Spectroscopic Instrument (DESI) is a robotic instrument and spectrograph mounted on the Mayall Telescope in Kitt Peak, Arizona. The DESI collaboration aims primarily to understand the elusive Dark Energy. This is an energy of unknown source causing the Universe to accelerate in its expansion; this accelerating expansion is not predicted to occur for a universe that is filled with just ordinary matter and radiation (some more detail can be seen in this Astrobite). Since we still know so little about Dark Energy, a large galaxy survey can allow us to explore the history of the expansion of the Universe in more detail. The DESI instrument has 5,000 individual optical fibres controlled by robots that allow it to measure individual spectra of up to 5,000 galaxies in just a mere 20 minutes! Due to this design, and an observing program that optimises targets in the sky based on observing conditions, the survey will measure spectra of up to 35 million galaxies over 5 years. This will allow DESI to perform precise cosmological measurements, as a great volume of space and number of galaxies can be probed, and noise in the data products is reduced. This bite looks at the cosmology results from the collaboration’s analysis of the recently released Year 1 Data (YR1), in particular, via a signal that can be seen in the data known as Baryon Acoustic Oscillations.

DESI tracers

For the cosmological results in this work DESI uses information from various different ‘tracers’ – galaxies that trace the Large Scale Structure of the Universe. These consist of low redshift bright galaxies (BGS) that are measured when the moon lights the sky (and thus dimmer galaxies are less visible), and higher redshift galaxies measured during the dark time. The dimmer objects include luminous red galaxies (LRGs) which are elliptical galaxies that are extremely bright, emission line galaxies (ELGs) which are younger galaxies with emission line features in their spectra, and quasars (QSOs) which are very distant and bright galaxies that contain active galactic nuclei. The sample used also includes QSOs detected using Lyman-alpha forest measurements, or a method of tracing matter that utilises a series of absorption lines detected due to light from distant QSOs passing through neutral hydrogen in the space between us and the distant galaxies.

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The accelerated expansion of the present universe, believed to be driven by a mysterious dark energy, is one of the greatest puzzles in our understanding of the cosmos. The standard model of cosmology called Lambda-CDM, explains this expansion as a cosmological constant in Einstein’s field equations. However, the cosmological constant itself lacks a complete theoretical understanding, particularly regarding its very small positive value.

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What makes PSR J1748–2446 famous for its weirdness? Easy. It is the celestial object that spins the fastest in the universe. It’s also a star whose surface is not just solid, but harder than a diamond. Compared to lead, its density is 50 trillion times higher. Compared to our Sun, its magnetic field sizzles a trillion times more intensely. It is, in essence, the most extreme form of neutron star.

When a heavy sun explodes in a supernova, the core of the sun, which has the mass of several million Earths, collapses into a tiny sphere and the rest of the sun shoots outward. This is how neutron stars are created. When this occurs, the inverse-square law of gravity goes into its demo-mode with a vengeance.

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