Astronomy Archives

December 22, 2023December 22, 2023 by Matt Williams

NASA Tightbeams a Cat Video From 31 Million Kilometers Away

This 15-second clip shows the first ultra-high-definition video sent via laser from deep space, featuring a cat named Taters chasing a laser with test graphics overlayed. Credit: NASA/JPL-Caltech

NASA’s Deep Space Network (DSN) has been responsible for maintaining contact with missions venturing beyond Low Earth Orbit (LEO) since 1963. In addition to relaying communications and instructions, the DSN has sent breathtaking images and invaluable science data back to Earth. As missions become more sophisticated, the amount of data they can gather and transmit is rapidly rising. To meet these growing needs, NASA has transitioned to higher-bandwidth radio spectrum transmissions. However, there is no way to increase data rates without scaling the size of its antennas or the power of its radio transmitters.

To meet these needs, NASA has created the Deep Space Optical Communications (DSOC), which relies on focused light (lasers) to stream very high-bandwidth video and other data from deep space. Compared to conventional radio, optical arrays are typically faster, more secure, lighter, and more flexible. In a recent test, NASA used this technology demonstrator to beam a video to Earth from a record-setting distance of 31 million km (19 million mi) – about 80 times the distance between the Earth and the Moon. The video, featuring a cat named Taters, marks a historic milestone and demonstrates the effectiveness of optical communications.

December 22, 2023December 22, 2023 by Matt Williams

Watch 14 Years of Gamma-Ray Observations in This Fascinating NASA Video

Still from the video showing 14 years of data gathered by the Fermi Gamma-ray Space Telescope. Credit: NASA Goddard

The Fermi Gamma-ray Space Telescope, named in honor of noted physicist Enrico Fermi, has been in operation for almost a decade and a half, monitoring the cosmos for gamma rays. As the highest-energy form of light, these rays are produced by extremely energetic phenomena – like supernovae, neutron stars, quasars, and gamma-ray bursts (GRBs). In honor of this observatory’s long history, NASA’s Goddard Spaceflight Center has released a time-lapse movie that shows data acquired by the Fermi Space Telescope between August 2008 and August 2022.

December 22, 2023December 22, 2023 by Paul M. Sutter

Holograms Might Save Physics

Observations made with ESO’s Very Large Telescope (VLT) have revealed for the first time that a star orbiting the supermassive black hole at the centre of the Milky Way moves just as predicted by Einstein’s theory of general relativity. Its orbit is shaped like a rosette and not like an ellipse as predicted by Newton's theory of gravity. This effect, known as Schwarzschild precession, had never before been measured for a star around a supermassive black hole. This artist’s impression illustrates the precession of the star’s orbit, with the effect exaggerated for easier visualisation.

Even though the guts of General Relativity are obtusely mathematical, and for decades was relegated to math departments rather than proper physics, you get to experience the technological gift of relativity every time you navigate to your favorite restaurant. GPS, the global positioning system, consists of a network of orbiting satellites constantly beaming out precise timing data. Your phone compares those signals to figure out where you are on the Earth. But there is a difference in spacetime between the surface of the Earth and the orbit of the satellites. Without taking general relativity into account, your navigation would simply be incorrect, and you’d be late for dinner.

December 22, 2023December 22, 2023 by Scott Alan Johnston

Ouch. Canadarm2 Took a Direct Hit From a Micrometeorite

Canadarm with a micrometeorite impact: ESA/NASA-A.Mogensen.

Living in space comes with risks. For astronauts on the International Space Station (ISS), those risks occasionally make themselves intrusively apparent.

Earlier this month, European Space Agency astronaut Andreas Mogensen snapped a photo of the Canadarm2, in which damage from a micrometeorite impact is clearly visible.

December 21, 2023December 22, 2023 by Carolyn Collins Petersen

Should We Be Preparing for First Contact?

First Contact. It’s a topic guaranteed to inspire a mix of emotions in people. It’s also one of the most fascinating SF scenarios we can imagine. What will people do when “they” appear? Or when we find evidence of life elsewhere in the Universe? For answers, one suggestion is to turn to a discipline called “exosociology”.

December 21, 2023December 21, 2023 by Andy Tomaswick

Lost In Space? Just Use Relativity

One of the hardest things for many people to conceptualize when talking about how fast something is going is that they must ask, “Compared to what?” All motion only makes sense from a frame of reference, and many spacecraft traveling in the depths of the void lack any regular reference from which to understand how fast they’re going. There have been several different techniques to try to solve this problem, but one of the ones that have been in development the longest is StarNAV – a way to navigate in space using only the stars.

December 21, 2023December 21, 2023 by Matt Williams

We Just had the Strongest Solar Flare in the Current Solar Cycle

A solar flare erupts on the Sun. Credit: NASA/GSFC/SDO

On December 14th, at 12:02 PM Eastern (09:02 AM Pacific), the Sun unleashed a massive solar flare. According to the Space Weather Prediction Center, part of the National Oceanic Atmospheric Administration (NOAA), this was the strongest flare of Solar Cycle 25, which began in 2019 and will continue until 2030. What’s more, scientists at the SWPC estimate that this may be one of the most powerful solar flares recorded since 1755 when extensive recording of solar sunspot activity began.

December 21, 2023December 18, 2023 by Paul M. Sutter

Why the Universe Might be a Hologram

The colored circle represents the hologram, out of which the knotted optical vortex emerges. Credit: University of Bristol

A quarter century ago, physicist Juan Maldacena proposed the AdS/CFT correspondence, an intriguing holographic connection between gravity in a three-dimensional universe and quantum physics on the universe’s two-dimensional boundary. This correspondence is at this stage, even a quarter century after Maldacena’s discovery, just a conjecture. A statement about the nature of the universe that seems to be true, but one that has not yet been proven to actually reflect the reality that we live in. And what’s more, it only has limited utility and application to the real universe.

December 20, 2023December 21, 2023 by Paul M. Sutter

The Strangest Coincidence in Physics: The AdS/CFT Correspondence

The west limb of the Sun imaged by NuSTAR and SDO shows areas of high-energy x-rays above particularly active regions (NASA/JPL-Caltech/GSFC)

Attempts to turn string theory into a workable theory of nature have led to the potential conclusion that our universe is a hologram: that what we perceive as three spatial dimensions is actually composed of only two. The greatest realization of this hologram-led program is a proposal that goes by the awkward and clunky name of the AdS/CFT correspondence, first proposed by string theorist Juan Maldacena in the late 1990’s.

December 19, 2023December 19, 2023 by Evan Gough

Can Webb Find the First Stars in the Universe?

The Universe’s very first stars had an important job. They formed from the primordial elements created by the Big Bang, so they contained no metals. It was up to them to synthesize the first metals and spread them out into the nearby Universe.

The JWST has made some progress in finding the Universe’s earliest galaxies. Can it have the same success when searching for the first stars?