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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Barred Spiral Galaxy NGC 2608, Surrounded by Many Many Other Galaxies

Looking deep into the Universe, the NASA/ESA Hubble Space Telescope catches a passing glimpse of the numerous arm-like structures that sweep around this barred spiral galaxy, known as NGC 2608. Appearing as a slightly stretched, smaller version of our Milky Way, the peppered blue and red spiral arms are anchored together by the prominent horizontal central bar of the galaxy. In Hubble photos, bright Milky Way stars will sometimes appear as pinpoints of light with prominent lens flares. A star with these features is seen in the lower right corner of the image, and another can be spotted just above the pale centre of the galaxy. The majority of the fainter points around NGC 2608, however, lack these features, and upon closer inspection they are revealed to be thousands of distant galaxies. NGC 2608 is just one among an uncountable number of kindred structures. Similar expanses of galaxies can be observed in other Hubble images such as the Hubble Deep Field which recorded over 3000 galaxies in one field of view.

Meet NGC 2608, a barred spiral galaxy about 93 million light years away, in the constellation Cancer. Also called Arp 12, it’s about 62,000 light years across, smaller than the Milky Way by a fair margin. The Hubble Space Telescope captured this image with its Wide-Field Camera 3 (WFC3).

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Newborn Exoplanets can be Completely Stripped of Their Atmosphere by Stars

Artist's conception of exoplanet systems that could be observed by PLAnetary Transits and Oscillations of stars (PLATO), a European Space Agency telescope. Credit: ESA - C. Carreau

Newborn exoplanets can have a tough life. They may form an atmosphere, but that atmosphere can be doomed. Their stars can emit intense X-ray and UV radiation, stripping away those atmospheres and laying their surfaces bare.

A team of researchers from the Leibniz Institute for Astrophysics looked at a family of four newborn sibling planets, and tried to understand how their star strips away their gaseous envelopes.

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Spacecraft was able to measure how long neutrons last before they decay

Artist's concept of the MESSENGER spacecraft on approach to Mercury. Credit: NASA/JPL

Using NASA’s MESSENGER spacecraft’s close encounters with Venus and Mercury, researchers were able to measure the lifetime of neutrons, an important prediction of the Standard Model of particle physics.

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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 Pictures of Phobos, Seen in the Infrared

Six views of the Martian moon Phobos captured by NASA's Odyssey orbiter as of March 2020. The orbiter's THEMIS camera is used to measure temperature variations that suggest what kind of material the moon is made of. Credit: NASA/JPL-Caltech/ASU/NAU

NASA’s Mars Odyssey Orbiter doesn’t get a lot of headlines lately. It was sent to Mars in 2001, to detect the presence of water and ice on Mars, or the past presence of it. It also looked at Mars’ geology and radiation. It’s been doing its job without a lot of fanfare.

Now Odyssey’s infrared camera has given us three new images of Mars’ moon Phobos.

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Scientists are much better at predicting when the Sun is going to become more active

A massive prominence erupts from the surface of the sun. Credit: NASA Goddard Space Flight Center

The sun constantly cycles between periods of activity and periods of inactivity, and a new technique allows scientists to better predict when things will start getting interesting.

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Well. It Looks Like James Webb is Getting Delayed Again, but it Should Still Launch in 2021

The James Webb Space Telescope's Engineering Design Unit (EDU) primary mirror segment, coated with gold. Image Credit: NASA/Drew Noel

This is probably one of the least surprising announcements to come out of the coronavirus pandemic.

During a virtual meeting of the National Academies’ Space Studies Board, NASA’s associate administrator for science, Thomas Zurbuchen, made an announcement. He said there’s no way the James Webb Space Telescope (JWST) will meet its target launch date of March 2021.

Already on a tight timeline, work on the telescope has slowed during the pandemic.

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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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