Universe Today

September 20, 2023September 20, 2023 by Matt Williams

We Should Be Looking for Small, Hot Dyson Spheres

A Type II civilization is one that can directly harvest the energy of its star using a Dyson Sphere or something similar. Credit: Fraser Cain (with Midjourney)

In 1960, legendary physicist Freeman Dyson published his seminal paper “Search for Artificial Stellar Sources of Infrared Radiation,” wherein he proposed that there could be extraterrestrial civilizations so advanced that they could build megastructures large enough to enclose their parent star. He also indicated that these “Dyson Spheres,” as they came to be known, could be detected based on the “waste heat” they emitted at mid-infrared wavelengths. To this day, infrared signatures are considered a viable technosignature in the Search for Extraterrestrial Intelligence (SETI).

So far, efforts to detect Dyson Spheres (and variation thereof) by their “waste heat” signatures have come up empty, leading some scientists to recommend tweaking the search parameters. In a new paper, astronomy and astrophysics Professor Jason T. Wright of the Center for Exoplanets and Habitable Worlds and the Penn State Extraterrestrial Intelligence Center (PSTI) recommends that SETI researchers refine the search by looking for indications of activity. In other words, he recommends looking for Dyson Spheres based on what they could be used for rather than just heat signatures.

September 20, 2023September 20, 2023 by Nancy Atkinson

Curiosity Has Spent Three Years Trying to Reach This Spot on Mars

NASA’s Curiosity captured this 360-degree panorama while parked below Gediz Vallis Ridge (seen at right), a formation that preserves a record of one of the last wet periods seen on this part of Mars. After previous attempts, the rover finally reached the ridge on its fourth try. Credits: NASA/JPL-Caltech/MSSS.

About three billion years ago, rushing water on Mars carried mud and boulders down a steep slope and deposited them into a vast fan-shaped debris pile. NASA’s Curiosity Rover has been trying to reach a ridge overlooking the region, and now finally, the rover has reached this vantage point after three years of climbing. NASA released a 360-degree view image of the region, showing the jumble of rocks strewn about by the rushing water. Now, Curiosity is reaching out to touch and study them.

September 20, 2023September 20, 2023 by Brian Koberlein

First Contact Could Turn Out Well for Humanity

Illustration of a radio telescope listening for signals from an alien civilization. Credit: Zayna Sheikh, Breakthrough Listen

You’ve heard this story before. An advanced alien race comes to Earth. They offer peace and prosperity, but they hold a dark secret. One that could destroy humanity. That dark secret has varied over the years, from stealing our water, books on culinary advice, or communism, but the result is always the same. First contact with advanced extraterrestrials goes very badly for us. But in reality, how bad could it be? That’s the question a new study examines using game theory and Hobbesian philosophy.

September 20, 2023September 20, 2023 by David Dickinson

Introducing Magic: Analog Sky’s New 3D Printed Binoculars for Astronomy

A new project promises to ‘bring back the magic’ to night sky observing.

When it comes to deep sky observing versus portability, we’ve all been there. How do you balance the trade-off between big complicated optics, with something basic and simple to use? We’ll make a small confession: while big light bucket optics have their place in astronomy, only binoculars give you a true view of the sky.

September 19, 2023September 19, 2023 by Carolyn Collins Petersen

The Race to Find the Farthest Galaxy Continues

Scientists with the CEERS Collaboration have identified an object (Maisie’s galaxy) that may be one of the earliest and farthest galaxies ever observed. Credit: NASA/STScI/CEERS/TACC/S. Finkelstein/M. Bagley/Z. Levay.

The very early Universe was a busy place, particularly when stars and galaxies began to form. Astronomers eagerly search for the farthest galaxy—that elusive “first” one to form. JWST is part of that hunt through its Cosmic Evolution Early Release Survey (CEERS).

September 19, 2023September 19, 2023 by Evan Gough

Galaxies Breathe Gas, and When They Stop, No More Stars Form

Artist concept of how a galaxy might accrete mass from rapid, narrow streams of cold gas. These filaments provide the galaxy with continuous flows of raw material to feed its star-forming at a rather leisurely pace. Credit: ESA–AOES Medialab

For most of the history of astronomy, all we could see were stars. We could see them individually, in clusters, in nebulae, and in fuzzy blobs that we thought were clumps of stars but were actually galaxies. The thing is, most of what’s out there is much harder to see than stars and galaxies. It’s gas.

Now that astronomers can see gas better than ever, we can see how galaxies breathe it in and out. When they stop breathing it, stars stop forming.

September 19, 2023September 19, 2023 by Brian Koberlein

Polar Ring Galaxies Are Bizarre and Rare. Astronomers Just Found Two More

A galaxy with a polar ring of hydrogen gas, known as a polar ring galaxy. Credit: Jayanne English, Nathan Deg & WALLABY Survey, CSIRO/ASKAP, NAOJ/Subaru Telescope

Galaxies come in a range of shapes, from elegant spirals to egg-shaped ellipticals. We often categorize galaxies by their shape, which was traditionally done based on what we could observe in the visual spectrum. But as we expanded astronomy into radio, infrared, ultraviolet, and x-ray light, learned that often galaxies have structures invisible to our eyes. Take, for example, an odd type of galaxy known as polar ring galaxies (PRGs).

September 19, 2023September 19, 2023 by Nancy Atkinson

Spacecraft Could be Equipped With Tiny Thrusters That Use Water for Propellant

A micro thruster developed at Imperial College is only 1 mm long. Credit: Imperial College/ESA

Engineers working with the European Space Agency have developed a new thruster design smaller than the tip of your finger. Despite its small size, this mini-thruster designed for CubeSats appears to be highly efficient without the use of toxic chemicals.

September 18, 2023September 18, 2023 by Carolyn Collins Petersen

A Collision Between Gigantic Galaxy Clusters. Too Big, Too Early

Hubble Space Telescope image of the El Gordo galaxy cluster. This and other gigantic galaxy clusters are challenging the most common theory of the evolution of structure in the Universe. Credit: NASA, ESA, and J. Jee (University of California, Davis)

Just when cosmologists have a workable theory for when and how galaxy collisions happened in the early Universe, something challenges it. In this case, the challenger is a collision of two massive galaxy clusters that combined to form a gigantic galaxy cluster.

September 18, 2023September 18, 2023 by Brian Koberlein

An Ambitious New Technology Might be Needed to See Other Earths

How a starshade would reveal exoplanets. Credit: NASA/JPL

The race is on to discover truly habitable Earth-like worlds. While we are starting to observe the atmospheres of large potentially habitable planets such as Hycean worlds with the telescopes we currently have, the most significant breakthroughs will likely come with the development of advanced specialized telescopes. These new designs will likely use a starshade to hide the glare of a star and allow us to directly observe its exoplanets. But will that be enough to study distant terrestrial planets?