A Gravity Map of Mars Uncovers Subsurface Mysteries

In this new gravity map of Mars, the red circles show prominent volcanoes and the black circles show impact craters with a diameter larger than a few 100 km. A gravity high signal is located in the volcanic Tharsis Region (the red area in the center right of the image), which is surrounded by a ring of negative gravity anomaly (shown in blue). Credit: Root et al.

A team of scientists presented a new gravity map of Mars at the Europlanet Science Congress 2024. The map shows the presence of dense, large-scale structures under Mars’ long-gone ocean and that mantle processes are affecting Olympus Mons, the largest volcano in the Solar System.

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If Gravitons Exist, this Experiment Might Find Them

It’s thought that gravity consists of minute quantum building blocks called gravitons, but so far they have been too elusive to observe. A new result from Pikovski’s Research Group now shows that next-generation quantum sensors can catch a single one.

There are four fundamental forces in the Universe; strong, weak, electromagnetic and gravity. Quantum theory explains three of the four through the interaction of particles but science has yet to discover a corresponding particle for gravity. Known as the ‘graviton’, the hypothetical gravity particle is thought to constitute gravitational waves but it hasn’t been detected in gravity wave detector. A new experiment hopes to change that using an acoustic resonator to identify individual gravitons and confirm their existence. 

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A NASA Rocket Has Finally Found Earth’s Global Electric Field

NASA's Endurance Rocket lifts off from Svalbard in 2022. The results are in and the rocket successfully measured Earth's global electric field. Image Credit: NASA/Brian Bonsteel

Scientists have discovered that Earth has a third field. We all know about the Earth’s magnetic field. And we all know about Earth’s gravity field, though we usually just call it gravity.

Now, a team of international scientists have found Earth’s global electric field.

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Will Wide Binaries Be the End of MOND?

Artist view of an orbiting binary star. Credit: ESO/L. Calçada

It’s a fact that many of us have churned out during public engagement events; that at least 50% of all stars are part of binary star systems. Some of them are simply stunning to look at, others present headaches with complex orbits in multiple star systems. Now it seems wide binary stars are starting to shake the foundations of physics as they question the very theory of gravity. 

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It's Official, Antimatter Falls Down in Gravity, Not Up

Illustration of how anti-hydrogen can test gravity. Credit: National Science Foundation

It’s a basic fact we’ve all learned in school. Drop any object, be it a baseball, feather, or cat, and it will fall toward the Earth at exactly the same rate. The cat will fortunately land on its feet thanks to a bit of feline grace, but the point is that everything falls at the same rate under gravity. It doesn’t matter what an object is made of, or how heavy it is. While we’ve all been taught this fact, calling it a fact was, until recently, a bit of a lie.

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Two New Space Telescopes Will Bring Dark Energy Into Focus

High-resolution illustration of the Euclid and Roman spacecraft against a starry background. Credits: NASA’s Goddard Space Flight Center, ESA/ATG medialab

Since the 1990s, thanks to observations by the venerable Hubble Space Telescope (HST), astronomers have contemplated the mystery of cosmic expansion. While scientists have known about this since the late-1920s and early-30s, images acquired by Hubble‘s Ultra Deep Fields campaign revealed that the expansion has been accelerating for the past six billion years! This led scientists to reconsider Einstein’s theory that there is an unknown force in the Universe that “holds back gravity,” which he named the Cosmological Constant. To astronomers and cosmologists today, this force is known as “Dark Energy.”

However, not everyone is sold on the idea of Dark Energy, and some believe that cosmic expansion could mean there is a flaw in our understanding of gravity. In the near future, scientists will benefit from next-generation space telescopes to provide fresh insight into this mysterious force. These include the ESA’s Euclid mission, scheduled for launch this July, and NASA’s Nancy Grace Roman Space Telescope (RST), the direct successor to Hubble that will launch in May 2027. Once operational, these space telescopes will investigate these competing theories to see which holds up.

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Many Astronauts Never Recover all of their Bone Density after Returning to Earth

In his book, Endurance, astronaut Scott Kelly described the arduous task of readjusting to life on Earth after spending a year in space. As part of NASA’s Twins Study, Kelly lived and worked aboard the International Space Station (ISS) while his identical twin (astronaut Mark Kelly) remained on Earth. While the results of this study revealed how prolonged exposure to microgravity could lead to all manner of physiological changes, the long and painful recovery Kelly described in his book painted a much more personal and candid picture.

As it turns out, astronauts who spend extended periods in space may never fully recover. At least, that is the conclusion reached by an international team led by the University of Calgary after they assessed the bone strength of multiple astronauts before and after they went to space. They found that after twelve months of recovery, the astronaut’s bones had not regenerated completely. These findings could have significant implications for proposed future missions, many of which involve long-duration stays in space, on the Moon, and Mars.

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What is Einstein’s Theory of Relativity?

Einstein Lecturing
Albert Einstein during a lecture in Vienna in 1921. Credit: National Library of Austria/F Schmutzer/Public Domain

In the history of science and physics, several scholars, theories, and equations have become household names. In terms of scientists, notable examples include Pythagoras, Aristotle, Galileo, Newton, Planck, and Hawking. In terms of theories, there’s Archimede’s “Eureka,” Newton’s Apple (Universal Gravitation), and Schrodinger’s Cat (quantum mechanics). But the most famous and renowned is arguably Albert Einstein, Relativity, and the famous equation, E=mc2. In fact, Relativity may be the best-known scientific concept that few people truly understand.

For example, Einstein’s Theory of Relativity comes in two parts: the Special Theory of Relativity (SR and the General Theory of Relativity (GR). And the term “Relativity” itself goes back to Galileo Galilee and his explanation for why motion and velocity are relative to the observer. As you can probably tell, explaining how Einstein’s groundbreaking theory works require a deep dive into the history of physics, some advanced concepts, and how it all came together for one of the greatest minds of all time!

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If Planet 9 is out There, Here's Where to Look

Illustration of the hypothetical Planet 9. Credit: R. Hurt/IPAC, Caltech

There are eight known planets in the solar system (ever since Pluto was booted from the club), but for a while, there has been some evidence that there might be one more. A hypothetical Planet 9 lurking on the outer edge of our solar system. So far this world has eluded discovery, but a new study has pinned down where it should be.

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Fantastic Visualization Shows What Would Happen if you Dropped a Ball Across the Solar System

Screen shot of ball drop across the solar system video.

Summertime means it’s time to play ball! But what would it be like to play ball on various locations across our Solar System? Planetary scientist Dr. James O’Donoghue has put together a fun animation of how quickly an object falls on to the surfaces of places like the Sun, Earth, Ceres, Jupiter, the Moon, and Pluto.

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