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Fossil galaxy buried in Milky Way + Arecibo telescope is toast, will SETI suffer?

#1
C C Offline
Astronomers discover new 'fossil galaxy' buried deep within the Milky Way
https://phys.org/news/2020-11-astronomer...milky.html

EXCERPTS: Scientists working with data from the Sloan Digital Sky Surveys' Apache Point Observatory Galactic Evolution Experiment (APOGEE) have discovered a "fossil galaxy" hidden in the depths of our own Milky Way. This result, published today in Monthly Notices of the Royal Astronomical Society, may shake up our understanding of how the Milky Way grew into the galaxy we see today.

The proposed fossil galaxy may have collided with the Milky Way ten billion years ago, when our galaxy was still in its infancy. Astronomers named it Heracles, after the ancient Greek hero who received the gift of immortality when the Milky Way was created. The remnants of Heracles account for about one third of the Milky Way's spherical halo. But if stars and gas from Heracles make up such a large percentage of the galactic halo, why didn't we see it before? The answer lies in its location deep inside the Milky Way.

[...] To separate stars belonging to Heracles from those of the original Milky Way, the team made use of both chemical compositions and velocities of stars measured by the APOGEE instrument. "Of the tens of thousands of stars we looked at, a few hundred had strikingly different chemical compositions and velocities," Horta said. "These stars are so different that they could only have come from another galaxy. By studying them in detail, we could trace out the precise location and history of this fossil galaxy."

Because galaxies are built through mergers of smaller galaxies across time, the remnants of older galaxies are often spotted in the outer halo of the Milky Way, a huge but very sparse cloud of stars enveloping the main galaxy. But since our galaxy built up from the inside out, finding the earliest mergers requires looking at the most central parts of the Milky Way's halo, which are buried deep within the disc and bulge... (MORE - details)



Without the Arecibo telescope, our search for intelligent life is hamstrung
https://www.engadget.com/what-were-losin...40347.html

EXCERPTS: Structural engineers and repair crews have done all that they can but the end result is as we feared: the Arecibo radio telescope has to come down. The venerable space observatory has been out of commission since August when a cable atop Tower 4, which supports the platform, snapped and gutted a 100-foot long section from the telescope’s reflecting dish. At the time, the University of Florida, which runs the facility on behalf of the National Science Foundation, deployed three different engineering teams to investigate the problem. [...] “The telescope is in danger of catastrophic failure,” the NSF wrote in a November statement. “Any attempts at repairs could put workers in potentially life-threatening danger.” As such, the NSF announced on Thursday that it will be dismantling the array before it can come crashing down on its own.

[...] In 1959, Cornell University contracted with ARPA to manage a gargantuan new radio telescope being built in the karst foothills, just outside Arecibo, Puerto Rico. ... Completed in 1963, the Arecibo telescope was initially tasked with studying the ionosphere ... However the reasoning behind the telescope’s construction actually grew out of an ARPA defense program which sought to create an early detection system for incoming nuclear missiles ... The telescope was also clandestinely used to snoop for Soviet radar sites by detecting signals bounced off the moon.

The Arecibo telescope was simply massive. Its primary collection dish measures more than a 1,000 meters in diameter [...] With a total collection area of 73,000 square meters (roughly 20 square acres), the NAIC stood as the largest single aperture telescope on the planet from the date of its completion in 1963 to 2016 when China completed its FAST telescope...

Its gigantic footprint allowed the Arecibo telescope capabilities that smaller sites simply could not match. [...] It was used in a wide array of scientific studies -- observing everything from the Earth’s upper atmosphere and the heliophysics of the sun to distant fast radio bursts and pulsar emissions. ... The telescope has also provided an invaluable aid in the search for extraterrestrial life... “I'd say that the Arecibo closing is bad for SETI, but not disastrous,” Dr. Christopher Conselice ... told Engadget. “It is a very sensitive telescope for searching for [extraterrestrial] signals but is not the only game in town anymore.”

[...] The telescope had experienced a number of difficulties in recent decades including damage from Hurricane Maria in 2017 and unreliable funding. Still, the NSF’s decision has come as a gut punch to the scientific community. ... "For nearly six decades, the Arecibo Observatory has served as a beacon for breakthrough science and what a partnership with a community can look like,” NSF Director Sethuraman Panchanathan said in a statement Thursday. “While this is a profound change, we will be looking for ways to assist the scientific community and maintain that strong relationship with the people of Puerto Rico." (MORE - details)
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#2
stryder Offline
In regards to Arecibo and SETI (albeit against my personal views) the fact that the telescope has lasted a time and is now at the brink of collapse also brings a valid point to signalling.

If there was an intelligent species out there using primative (by their standards) radio frequency to broadcast out into the universe, the equipment they use would either have to be maintained or replaced regularly, otherwise it would be just pure luck if anyone did spot anything.

Personally I'd think the evolution of communication will use non-locality, which means the usage of dopplers would become obsolete for communication.
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