Hundreds of New Gravitational Lenses Discovered to Help Study the Distant Universe

These two columns show side-by-side comparisons of gravitational lens candidates imaged by the ground-based Dark Energy Camera Legacy Survey (color) and the Hubble Space Telescope (black and white). (Credit: Dark Energy Camera Legacy Survey, Hubble Space Telescope)
These two columns show side-by-side comparisons of gravitational lens candidates imaged by the ground-based Dark Energy Camera Legacy Survey (color) and the Hubble Space Telescope (black and white). (Credit: Dark Energy Camera Legacy Survey, Hubble Space Telescope)

General relativity tells us that everything, even light, is affected by the mass of an object. When a beam of light passes near a large mass, its path is deflected. This shift in the direction of light is known as gravitational lensing, and it was one of the first confirmed effects of Einstein’s theory.

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The Tunguska Explosion Could Have Been Caused By An Asteroid That Still Orbits The Sun

Impact zone of the 1908 Tunguska Event. Credit: Wikipedia user Denys

On a cool Summer morning in 1908, a fireball appeared over Northern Siberia. Eyewitnesses described a column of blue light that moved across the sky, followed by a tremendous explosion. The explosion leveled trees across more than 2,000 square kilometers. The explosion is consistent with a large meteor strike, but to this day no evidence of a crater has been found. Now known as the Tunguska Event, its cause remains a mystery to this day.

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High Energy Neutrinos Are Coming From Supermassive Black Holes

ANITA being prepared for launch. Credit: NASA Goddard

Neutrinos are mysterious and elusive particles. They have a tiny mass, no electric charge, and they interact with other matter only rarely. They are also extremely common. At any moment, about 100 billion neutrinos are streaming through every square centimeter of your body. Neutrinos were produced by the big bang, and are still being produced by everything from stars to supernovae.

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One Step Closer to Interstellar Travel. A Successful Microgravity Test of a Graphene Light Sail

Artist concept of lightsail craft approaching the potentially habitable exoplanet Proxima b. Credit: PHL @ UPR Arecibo

If we want to travel to the stars, we’re going to have to be creative. Conventional rockets aren’t nearly powerful enough to allow us to journey across light-years in a reasonable time. Even nuclear rockets might not be enough. So what’s humanity to do? The answer could be a light sail.

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A Fast Radio Burst Has Been Detected From Inside The Milky Way

An illustration fast radio bursts in the night sky. Credit: James Josephides/Mike Dalley

Now and then there are bright flashes of radio light in the sky, and they are bothering astronomers. They are called Fast Radio Bursts (FRBs), and they’re like the chirp of a smoke alarm that needs its battery changed. They last for such a short time that it’s difficult to track down the source. They have become a nagging mystery in astronomy.

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The Sun is less active magnetically than other stars

GOES-17 Solar Ultraviolet Imager captures the Sun at different wavelengths. Credit: NOAA

Our Sun is the source of life on Earth. Its calm glow across billions of years has allowed life to evolve and flourish on our world. This does not mean our Sun doesn’t have an active side. We have observed massive solar flares, such as the 1859 Carrington event, which produced northern lights as far south as the Caribbean, and drove electrical currents in telegraph lines. If such a flare occurred in Earth’s direction today, it would devastate our electrical infrastructure. But fortunately for us, the Sun is mostly calm. Unusually calm when compared to other stars.

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Could The Physical Constants Change? Possibly, But Probably Not

A star is ripped apart by a black hole. Credit: Mark Garlick

The world we see around us seems to be rooted in scientific laws. Theories and equations that are absolute and universal. Central to these are fundamental physical constants. The speed of light, the mass of a proton, the constant of gravitational attraction. But are these constants really constant? What would happen to our theories if they changed?

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How Do You Weigh The Universe?

How do you weigh everything in the cosmos? Credit: ESO/T. Preibisch

The weight of the universe (technically the mass of the universe) is a difficult thing to measure. To do it you need to count not just stars and galaxies, but dark matter, diffuse clouds of dust and even wisps of neutral hydrogen in intergalactic space. Astronomers have tried to weigh the universe for more than a century, and they are still finding ways to be more accurate.

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Betelgeuse Is Bright Again

Artist's impression of Betelgeuse. Credit: ESO/L. Calçada

Everyone’s favorite red supergiant star is bright again. The American Association of Variable Star Observers (AAVSO) has been tracking Betelgeuse as it has gradually returned to its more normal brilliance. As of this writing, it is about 95% of its typical visual brightness. Supernova fans will have to wait a bit longer.

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Why was there more matter than antimatter in the Universe? Neutrinos might give us the answer

A neutrino detection event at Super-Kamiokande observatory. Credit: T2K Collaboration

The universe is filled with matter, and we don’t know why. We know how matter was created, and can even create matter in the lab, but there’s a catch. Every time we create matter in particle accelerators, we get an equal amount of antimatter. This is perfectly fine for the lab, but if the big bang created equal amounts of matter and antimatter, the two would have destroyed each other early on, leaving a cosmic sea of photons and no matter. If you are reading this, that clearly didn’t happen.

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