Radio Astronomers are Worried About Mega-Constellations and the Square Kilometer Array

Antennas of CSIRO’s Australian SKA Pathfinder with the Milky Way overhead. Credit: Alex Cherney/CSIRO

In the coming years, a number of next-generation observatories and arrays will become operational. These facilities will make major contributions to multiple fields of astronomy: exploring the mysteries of the early Universe, studying gravitational waves, determining the role of dark matter and dark energy in cosmic evolution, and directly image “Earth-like” exoplanets.

Unfortunately, this revolutionary development in astronomy may be going up against another major project: the creation of mega-constellations. Because of this, the SKA Organization (SKAO) – which oversees the international Square Kilometre Array (SKA) – is insisting that corrective measures be taken so satellites won’t interfere with its radio observations once it’s operational.

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New Radio Telescope Is Going to Fly to the Far Side of the Moon to Listen to the Signals From the Early Universe

The phrase “silence is golden” is even more important for radio astronomers.  The sheer amount of radio output created by humans can drown out any interesting signal from the heavens that they might wish to study.  Those signals are also partially blocked by Earth’s atmosphere, adding more complexity to the challenge.  

The obvious solution to the atmosphere problem is to launch space based observatories, and that has been done in the past.  However, in near Earth orbit the radio waves emitted from radio stations all around the world can still blast any radio receiver with an unwanted deluge of signals.  So scientists have come up with a novel idea to get the silence they so crave: park a probe on the far side of the moon.

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A Broken Cable Smashed Part of the Arecibo Observatory

Damage at the Arecibo Observatory in August, 2020. Credit: NSF/NAIC

The Arecibo Observatory is an iconic institution. Located in Puerto Rico, this National Science Foundation (NSF) observatory was the largest radio telescope in the world between 1963 and 2016. While that honor now goes to the Five hundred meter Aperture Spherical Telescope (FAST) in China, Arecibo will forever be recognized for its contributions to everything from radio astronomy to the Search for Extraterrestrial Intelligence (SETI).

Unfortunately, the Arecibo Observatory suffered serious damage when on Monday, Aug. 10th, an auxiliary cable that supports the platform suspended above the telescope reflector dish broke. The cable struck the Gregorian Dome (which sits on the underside of the platform) before landing on the reflector dish, which created a gash over 30 meters (100 feet) in length and forced the observatory to temporarily shut down operations.

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A Repeating Fast Radio Burst Has Been Found. It Flares for 4 Days and then Remains Silent for 12 Days

Artist’s impression of a fast radio burst traveling through space and reaching Earth. Credit: ESO/M. Kornmesser

Five hundred million light-years from Earth, there is a deeply unusual object. It is radio silent for 12 days, then erupts in bright radio bursts. These fast radio bursts occur randomly over four days, then the object goes silent for another 12 days. Astronomers have observed this object for 500 days, and the pattern always repeats, like clockwork. We still aren’t sure what the object is.

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Searching for the End of the Universe’s “Dark Age”

A ‘radio colour’ view of the sky above the Murchison Widefield Array radio telescope, part of the International Centre for Radio Astronomy Research (ICRAC). Credit: Radio image by Natasha Hurley-Walker (ICRAR/Curtin) and the GLEAM Team. MWA tile and landscape Credit: ICRAR/Dr John Goldsmith/Celestial Visions

According to the most widely accepted cosmological theories, the first stars in the Universe formed a few hundred million years after the Big Bang. Unfortunately, astronomers have been unable to “see” them since their emergence coincided during the cosmological period known as the “Dark Ages.” During this period, which ended about 13 billion years ago, clouds of gas filled the Universe that obscured visible and infrared light.

However, astronomers have learned that light from this era can be detected as faint radio signals. It’s for this reason that radio telescopes like the Murchison Widefield Array (MWA) were built. Using data obtained by this array last year, an international team of researchers is scouring the most precise radio data to date from the early Universe in an attempt to see exactly when the cosmic “Dark Ages” ended.

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Seti@home is on Pause. Unfortunately, it’s not Because They’ve Discovered Aliens

A home PC running SETI at Home helping to churn through observational data Credit: SETI@home

In May of 1999, the Berkeley SETI Research Center launched a citizen-science program that would make the Search for Extra-Terrestrial Intelligence (SETI) open to the public. The brainchild of computer scientist David Gedye, this program would rely on large numbers of internet-connected computers to sort through the volumes of data collected by institutions participating in SETI efforts.

The program was appropriately named SETI@home and would rely on the computers of volunteers to process radio signals for signs of transmissions. And after twenty years, the program recently announced that it has gone into hibernation. The reason, they claim, is that the program’s network has become too big for its own britches and the scientists behind it need time to process and share all the results they’ve obtained so far.

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Astronomers Have Recorded the Biggest Explosion Ever Seen in the Universe

Hundreds of millions of light years away, a supermassive black hole sits in the center of a galaxy cluster named Ophiuchus. Though black holes are renowned for sucking in surrounding material, they sometimes expel material in jets. This black hole is the site of an almost unimaginably powerful explosion, created when an enormous amount of material was expelled.

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Detecting Exoplanets Through Their Exoauroras

Artistic impression of a red-dwarf star’s magnetic interaction with its exoplanet. Credit: Danielle Futselaar/

At present, scientists can only look for planets beyond our Solar System using indirect means. Depending on the method, this will involve looking for signs of transits in front of a star (Transit Photometry), measuring a star for signs of wobble (Doppler Spectroscopy), looking for light reflected from a planet’s atmosphere (Direct Imaging), and a slew of other methods.

Based on certain parameters, astronomers are then able to determine whether a planet is potentially-habitable or not. However, a team of astronomers from the Netherlands recently released a study in which they describe a novel approach for exoplanet-hunting: looking for signs of aurorae. As these are the result of interaction between a planet’s magnetic field and a star, this method could be a shortcut to finding life!

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A Rare Fast Radio Burst has been Found that Actually Repeats Every 16 Days

Taken with the HAWK-I instrument on ESO’s Very Large Telescope in the Chilean Atacama Desert, this stunning image shows the Milky Way’s central region with an angular resolution of 0.2 arcseconds. This means the level of detail picked up by HAWK-I is roughly equivalent to seeing a football (soccer ball) in Zurich from Munich, where ESO’s headquarters are located. The image combines observations in three different wavelength bands. The team used the broadband filters J (centred at 1250 nanometres, in blue), H (centred at 1635 nanometres, in green), and Ks (centred at 2150 nanometres, in red), to cover the near infrared region of the electromagnetic spectrum. By observing in this range of wavelengths, HAWK-I can peer through the dust, allowing it to see certain stars in the central region of our galaxy that would otherwise be hidden.   

A team of scientists in Canada have found a Fast Radio Burst (FRB) that repeats every 16 days. This is in stark contrast to other FRBs, which are more sporadic. Some of those sporadic FRBs occur in clusters, and repeat irregularly, but FRBs with a regular, repeatable occurrence are rare.

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