Perhaps the most commonplace and familiar use of a hologram is found on credit cards, such as the Visa “dove” hologram shown here. Holograms appear three-dimensional, but only require a two-dimensional surface to encode that information. (Credit: Dominic Alves/flickr)Holograms preserve all of an object’s 3D information, but on a 2D surface. Could the holographic Universe idea lead us to higher dimensions? Have you ever wondered whether there’s more to reality than what we can see, perceive, detect, or otherwise observe? One of the most intriguing but speculative ideas of 20th and 21st century ..read more

Although there are no observed white holes within our Universe, the theoretical description of one has many facets in common with what we identify as the hot Big Bang. There could be a connection between white holes and what happens on the other side of black holes, with implications for the origins of our own Universe. (Credit: daboost / Adobe Stock)In General Relativity, white holes are just as mathematically plausible as black holes. Black holes are real; what about white holes? In our Universe, the laws of physics tell us all the possibilities for what’s allowed to conceivably ex ..read more

The human mind is one of the great mysteries of modern science, as we cannot sufficiently explain how the brain in general, or consciousness in particular, works. However, it’s a reasonable “null hypothesis” to presume that electricity, i.e., the flow of electrons, is the primary driver behind our perceptions that we are conscious. Although quantum effects may play a role, it’s an unnecessary complication to presume that consciousness is anything other than the flow of electricity. (Credit: agsandrew/Adobe Stock)At a fundamental level, only a few particles and forces govern all of reality. How ..read more

Possible fates of the expanding Universe. Notice the differences between models in the past; only a Universe with dark energy matches our observations, and the dark energy-dominated solution came from de Sitter all the way back in 1917. By observing the expansion rate today and measuring the components present in the Universe, we can determine both its future and past histories. (Credit: NASA & ESA)Dark energy is one of the biggest mysteries in all the Universe. Is there any way to avoid “having to live with it?” When it comes to the Universe, it’s easy to make the incorrect assu ..read more

At any epoch in our cosmic history, any observer will experience a uniform “bath” of omnidirectional radiation that originated back at the Big Bang. Today, from our perspective, it’s just 2.725 K above absolute zero, and hence is observed as the cosmic microwave background, peaking in microwave frequencies. At great cosmic distances, as we look back in time, that temperature was hotter dependent on the redshift of the observed, distant object. As each new year passes, the CMB cools down further by about 0.2 nanokelvin, and in several billion years, will become so redshifted that it will posses ..read more

Here in our own Solar System, a single star anchors the system, where inner, rocky planets, an intermediate-distance asteroid belt, and then more distant gas giant planets eventually give way to the Kuiper belt and Oort cloud. For a long time, we assumed this configuration was typical and common. Today, we know better. (Credit: NASA/Dana Berry)For some reason, when we talk about the age of stars, galaxies, and the Universe, we use “years” to measure time. Can we do better? There are a number of grand questions we can ask about the Universe that cut right to the very core of what reality a ..read more

This Wolf–Rayet star is known as WR 31a, located about 30,000 light-years away in the constellation of Carina. The outer nebula is expelled hydrogen and helium, while the central star burns at over 100,000 K. In the relatively near future, many suspect that this star will explode in a supernova much like WR 124, enriching the surrounding interstellar medium with new, heavy elements. It cannot be predicted which evolved, massive star in our galaxy will be the Milky Way’s next supernova. (Credit: ESA/Hubble & NASA; Acknowledgement: Judy Schmidt)The most common element in the Universe, v ..read more

Intelligent aliens, if they exist in the galaxy or the Universe, might be detectable from a variety of signals: electromagnetic, from planet modification, or because they’re spacefaring. But we haven’t found any evidence for an inhabited alien planet so far. We may truly be alone in the Universe, but the honest answer is we don’t know enough about the relevant probabilities to draw definitive conclusions. Our first discovery of life beyond Earth still awaits. (Credit: Ryan Somma/flickr)Life arose on Earth very early on. After a few billion years, here we are: intelligent and technologically ad ..read more

In this artistic rendering, a blazar is accelerating protons that produce pions, which produce neutrinos and gamma rays. Photons are also produced. Extreme events in energy are generated by processes occurring around the largest supermassive black holes known in the Universe when they’re actively feeding, as well as around highly magnetic neutron stars and actively feeding stellar mass black holes. (Credit: IceCube collaboration/NASA)Our Universe requires dark matter in order to make sense of things, astrophysically. Could massive photons do the trick? When it comes to the Universe, there ..read more

Although, at a fundamental level, the Universe is made up of point-like quantum particles, they assemble together to create objects of finite sizes and masses, occupying specific amounts of volume. This artist’s illustration shows several electrons orbiting an atomic nucleus, where the electron is a fundamental particle, but the nucleus can be broken up into still smaller, more fundamental constituents. Whether there are structures on scales smaller than the presently known subatomic particles remains to be discovered. (Credit: Shutterstock)Practically all of the matter we see and interact wit ..read more