Universe Today

October 8, 2023October 8, 2023 by Brian Koberlein

Here's What it Would Take to See a Black Hole's Photon Ring

The EHT image of M87* compared to its photon ring. Credit: Left: EHT Collaboration, Right: A.E. Broderick et al, 2022

Supermassive black holes are elusive creatures. Massive gravitational beasts that can power immensely bright quasars, or can lurk quietly among the bright stars of a galactic core. We mostly study them indirectly through their bright accretion disks or powerful jets of plasma they create, but we have been able to observe them more directly, such as our images of M87* and Sag A*. But what still eludes us is capturing a direct image of the enigmatic photon ring. A new work in Acta Astronautica proposes how this might be done.

October 8, 2023October 8, 2023 by Scott Alan Johnston

M87's Jet is Triggering Novae

The jet emerging from the galactic core of M87. NASA/STScI/AURA.

Everyone loves a good mystery, and astronomers have just uncovered a new one in a nearby supermassive galaxy called M87. Like most galaxies, M87 regularly plays host to a smattering of stellar explosions called novae, each the result of a star stealing material from a neighbour. M87 also features a massive jet of plasma blasting out into deep space from the galactic core. These phenomena: the jet and the novae, are unrelated astronomical occurrences, or so scientists believed. But astronomers recently discovered that the novae in M87 seem to be uncharacteristically aligned along the jet, instead of scattered randomly throughout the galaxy. Is the jet somehow triggering nova explosions?

It might be, but the mystery is: how?

October 8, 2023October 8, 2023 by Andy Tomaswick

A Flock of CubeSats Will Use Wings to Maneuver at the Edge of Space

CubeSats are taking on more and more responsibility for remote monitoring of the Earth. As they become more ubiquitous, they will also gain more varied propulsion systems. Or, in the case of a new set of monitoring CubeSats from INTA, Spain’s Institue of Aerospace Technology, no propulsion system at all.

October 8, 2023October 8, 2023 by Andy Tomaswick

Future Moon and Mars Rovers Have a New Sandbox to Learn in

In-situ testing for space equipment is complex when it has to be developed on Earth, which is the case for literally all of it, at least for now. Typically, engineers and scientists developing the next Lunar or Martian robotic explorer would seek out exotic destinations that, while they look like they fit on another planet, were just more exotic parts of ours. The robotics team at DLR, Germany’s space agency, decided they could do better. So they built a 1500 sq meter test bed for their upcoming Martian and Lunar exploration bots.

October 7, 2023October 7, 2023 by Matt Williams

Hubble Sees a Mysterious Flash in Between Galaxies

Artist’s concept of one of brightest explosions ever seen in space: a Luminous Fast Blue Optical Transient (LFBOT). Credit: NASA

While the night sky may appear tranquil (and incredibly beautiful), the cosmos is filled with constant stellar explosions and collisions. Among the rarest of these transient events are what is known as Luminous Fast Blue Optical (LFBOTs), which shine intensely bright in blue light and fade after a few days. These transient events are only detectable by telescopes that continually monitor the sky. Using the venerable Hubble Space Telescope, an international team of astronomers recently observed an LFBOT far between two galaxies, the last place they expected to see one.

October 7, 2023October 7, 2023 by Brian Koberlein

Starlinks are Easily Detected by Radio Telescopes

Artist's impression of the 5km diameter central core of Square Kilometre Array (SKA) antennas. Credit: SPDO/TDP/DRAO/Swinburne Astronomy Productions

Radio astronomy and satellite communication have a long common history. Advances made in one field have benefitted the other, and our modern era of spacecraft and mobile internet is a product of this partnership. But there are times when the goals of radio astronomy and the goals of communication satellites are in opposition. This is most clearly seen in the development of satellite constellations such as Starlink.

October 7, 2023October 7, 2023 by Nancy Atkinson

This Moon Rover Wheel Could be 3D Printed on the Moon

NASA mechanical design engineer Richard Hagen, left, and ORNL researcher Michael Borish inspect a lunar rover wheel prototype that was 3D printed at the Manufacturing Demonstration Facility. Credit: Carlos Jones/ORNL, U.S. Dept. of Energy

When you think about sending missions to the Moon, every single gram counts on launch day. Therefore, it makes sense to live off the land when you arrive with in-situ resource utilization. For example, what if you could fly a rover without wheels and 3D print them out of lunar regolith when you get there?

It just might happen.

Researchers used a 3D printer to build the same design for a wheel that will be part of the upcoming NASA VIPER rover. It was done using additive manufacturing (another word for 3D printing), melting metal powder and laying down and bonding a large number of successive thin layers of materials into the designed shape.

October 6, 2023October 6, 2023 by Matt Williams

Colliding Neutron Stars Could Help Measure the Expansion of the Universe

Artist's impression of two neutron stars colliding, known as a "kilonova" event. Credits: Elizabeth Wheatley (STScI)

According to some in the astrophysical community, there has been something of a “Crisis in Cosmology” in recent years. Though astronomers are all aware that the Universe is in a state of expansion, there has been some inconsistency when measuring the rate of it (aka. the Hubble Constant). This issue arises from the Cosmic Distance Ladder, where astronomers use different methods to measure relative distances over longer scales. This includes making local distance estimates using parallax measurements, nearby variable stars, and supernovae (“standard candles”).

They also conduct redshift measurements of the Cosmic Microwave Background (CMB), the relic radiation left over from the Big Bang, to determine cosmological distances. The discrepancy between these two methods is known as the “Hubble Tension,” and astronomers are eager to resolve it. In a recent study, an international team of astrophysicists from the Niels Bohr Institute suggested a novel method for measuring cosmic expansion. They argue that by observing colliding neutron stars (kilonovae), astronomers can relieve the tension and obtain consistent measurements of the Hubble Constant.

October 6, 2023October 6, 2023 by Evan Gough

One of the Brightest Stars in the Sky is Actually a Satellite

The bright streaks drawing an arc across the night sky are caused by the satellite BlueWalker 3. The prototype satellite is brighter than most stars. Image Credit: Ilse Plauchu-Frayn

Back in the 70s, kids used to look up at the summer sky and try to be the first one to shout, “Satellite!” That seems like a relic from the past now, alongside Polaroid cameras and astronauts on the Moon. These days, it’s rare to spend any amount of time looking at the sky without seeing a satellite, or several of them.

A new satellite is emphasizing that fact. It’s a prototype communications satellite with a roughly 700-square-foot antenna, and it’s brighter than most stars.

October 6, 2023October 6, 2023 by Brian Koberlein

What Caused Eta Carinae’s 1840 “Great Eruption?”

Hubble image of Eta Carinae. Credit: NASA, ESA, N. Smith (University of Arizona), and J. Morse (BoldlyGo Institute)

In 1840 an unassuming star in the Southern Hemisphere brightened suddenly. What had been a 5th magnitude star became so bright by 1843 that it was the second brightest star in the sky. The star, known as Eta Carinae, had been known to vary in brightness before, but this change was so sudden and so dramatic that it became known as the Great Eruption.