Pulsars Confirm One of Einstein’s Best Ideas, That Freefall Really Feels Like You’re Experiencing a Lack of Gravity

This artist’s impression shows the exotic double object that consists of a tiny, but very heavy neutron star that spins 25 times each second, orbited every two and a half hours by a white dwarf star. The neutron star is a pulsar named PSR J0348+0432 that is giving off radio waves that can be picked up on Earth by radio telescopes. Although this unusual pair is very interesting in its own right it is also a unique laboratory for testing the limits of physical theories. This system is radiating gravitational radiation, ripples in spacetime. Although these waves cannot be yet detected directly by astronomers on Earth they can be detected indirectly by measuring the change in the orbit of the system as it loses energy. As the pulsar is so small the relative sizes of the two objects are not drawn to scale.

Six and a half decades after he passed away, famed theoretical physicist Albert Einstein is still being proven right! In addition to General Relativity (GR) being tested under the most extreme conditions, lesser-known aspects of his theories are still being validated as well. For example, GR predicts that gravity and inertia are often indistinguishable, in what is known as the gravitational Strong Equivalence Principle (SEP).

Thanks to an international team of researchers, it has been proven under the strongest conditions to date. By precisely tracking the motion of a pulsar, the team demonstrated that gravity causes neutron stars and white dwarf stars to fall with equal accelerations. This confirms Einstein’s prediction that freefall accurately simulates zero-gravity conditions in all inertial reference frames.

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Tiny Cubesat Detects an Exoplanet

Credit: NASA/JPL-Caltech

In the past decade and a half, a total of 4,164 thousand planets have been discovered beyond our Solar System, while another 5220 await confirmation. The majority of these were detected by the venerable Kepler Space Telescope, while the remainder have been observed by the Transitting Exoplanet Survey Satellite (TESS) and a combination of other satellites and ground-based telescopes.

But in what is a new record, a known super-Earth was recently observed by the Arcsecond Space Telescope Enabling Research in Astrophysics (ASTERIA) small satellite – making it the smallest observatory to spot an exoplanet. Led by a team from the Massachusetts Institute of Technology (MIT), this mission has demonstrated that small satellites can perform complex tasks in space normally carried out by large observatories.

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New Horizons is so Far From Earth That the Positions of the Stars Look a Little Different From its Perspective

Credit: NASA/JHUAPL

In July of 2015, the New Horizons spacecraft made history when it became the first robotic explorer to conduct a flyby of Pluto. This was followed by another first, when the NASA mission conducted the first flyby of a Kuiper Belt Object (KBO) on December 31st, 2018 – which has since been named Arrokoth. Now, on the edge of the Solar System, New Horizons is still yielding some groundbreaking views of the cosmos.

For example, we here on Earth are used to thinking that the positions of the stars are “fixed”. In a sense, they are, since their positions and motions are relatively uniform when seen from our perspective. But a recent experiment conducted by the New Horizons team shows how familiar stars like Proxima Centauri and Wolf 359 (two of the closest stars in our neighbors) look different when viewed from the edge of the Solar System.

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Ideas for Sustainable Cities and Urban Farming… on Mars?

Credit: MCD
“The core essence of Mars City Design is —not to repeat the same mistakes that we did to our planet. The hope to start a new design for living on Mars, every single thing needs to have a sustainable answer within the big picture, of the regenerative circle of life and of the product itself. All things need an exit plan that allows them to be reusable or repurposed. That can hopefully inspire change on Earth.”

-Vera Mulyani (Vera Mars), Founder/CEO Mars City Design

Once the stuff of science fiction, the possibility that humans could establish a permanent settlement on Mars now appears to be a genuine possibility. While doing so represents a major challenge and there are many hurdles that still need to be overcome, the challenge itself is inspiring some truly creative solutions. But what is especially interesting is how these same solutions can also address problems here on Earth.

This is especially clear where the Mars City Design Challenges are concerned. This annual competition was founded with the purpose of inspiring innovative ideas that could lead to sustainable living on Mars. For this year’s challenge, “Urban Farming for Extreme Environment,” Mars City Design and its founder (Vera Mulyani) are looking for designs that incorporate urban farming to support a colony of 100 people.

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At the Heart of the Milky Way, Stars Come Close to Each Other All the Time

The core of the Milky Way. Credit: NASA/JPL-Caltech/S. Stolovy (SSC/Caltech)

We here at Universe Today would like to express our support for Black Lives Matter and the countless people who are currently marching and demonstrating across Canada and the United States. To support Moiya and other black scientists and science communicators in STEM, we’ll be silent on Wednesday. Go to https://www.particlesforjustice.org/ for more info.

At the center of our galaxy resides the Galactic Bulge, a densely-packed region of stars, dust, and gas. Within this massive structure, which spans thousands of light-years, there are an estimated 10 billion stars, most of which are old red giant stars. Because of this density, astronomers have often wondered if a galactic bulge is a likely place to find stars with habitable planets orbiting them.

Essentially, stars that are closely packed together are more likely to experience close encounters with other stars, which can be catastrophic for any planets that orbit them. According to a new study from Columbia University’s Cool Worlds Lab, most stars in the Bulge will experience dozens of close encounters over the course of a billion years, which could have significant implications for long-term habitability in this region.

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Practical Ideas for Farming on the Moon and Mars

Credit: GrowMars/D. Tompkins

When the International Space Station (ISS) runs low on basic supplies – like food, water, and other necessities – they can be resupplied from Earth in a matter of hours. But when astronauts go the Moon for extended periods of time in the coming years, resupply missions will take much longer to get there. The same holds true for Mars, which can take months to get there while also being far more expensive.

It’s little wonder then why NASA and other space agencies are looking to develop methods and technologies that will ensure that their astronauts have a degree of self-sufficiency. According to NASA-supported research conducted by Daniel Tompkins of Grow Mars and Anthony Muscatello (formerly of the NASA Kennedy Space Center), ISRU methods will benefit immensely from some input from nature.

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Spying a Rare ‘Ring of Fire’ Around Venus at Inferior Conjunction

Amazing things happen in the day-to-day sky that often go unnoticed during our normal routine. Just such a curious ‘non-event’ happened this week, when Venus reached inferior conjunction between the Earth and the Sun on its race from the dusk to the dawn sky. And what’s even more amazing, is the fact that some skilled observers followed this passage and caught sight of Venus as a tiny blazing ‘ring of fire’ silhouetted against the dazzling sky.

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What are the Odds of Life Emerging on Another Planet?

Artist's impression of the Milky Way Galaxy. Credit: ESO

In 1961, famed astronomer and astrophysicist Frank Drake formulated an equation for estimating the number of extraterrestrial civilizations in our galaxy at any given time. Known as the “Drake Equation“, this formula was a probabilistic argument meant to establish some context for the Search for Extraterrestrial Intelligence (SETI). Of course, the equation was theoretical in nature and most of its variables are still not well-constrained.

For instance, while astronomers today can speak with confidence about the rate at which new stars form, and the likely number of stars that have exoplanets, they can’t begin to say how many of these planets are likely to support life. Luckily, Professor David Kipping of Columbia University recently performed a statistical analysis that indicates that a Universe teeming with life is “the favored bet.”

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How to See This Friday’s Penumbral Lunar Eclipse

Eclipse season resumes on June 5th, with a fine penumbral lunar eclipse.

Are you cursing the June Full Moon as it thwarts your dreams of deep-sky imaging this week? Fear not; said Moon is actually the first astronomical draw for June 2020, as this coming weekend’s Full Moon marks the start of second eclipse season for 2020, with a penumbral lunar eclipse.

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Rare “Ring Galaxy” Seen in the Early Universe

Credit: ASTRO 3D

One of the greatest benefits to come from space telescopes and ground-based observatories that take advantage of advanced imaging techniques is their ability to see farther into space (and hence, further back in time). In so doing, they are revealing things about the earliest galaxies, which allows astronomers to refine theories of how the cosmos formed and evolved.

For example, new research conducted by the ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D) has found a “ring galaxy” that existed 11 billion years ago (about 3 billion years after the Big Bang). This extremely rare structure, which the team describes as a “cosmic ring of fire,” is likely to shake up cosmological theories of how the cosmos has changed over time.

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