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Science Announcements, Articles, announcements, comments about science
mullokintyre
post Posted: Nov 28 2020, 09:01 AM
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The WOW! seti signal is still puzzling scientists even after 40 years.
FromHACK

QUOTE
On a balmy August evening in 1977, an enormous radio telescope in a field in the middle of Ohio sat silently listening to the radio universe. Shortly after 10:00 PM, the Earth’s rotation slewed the telescope through a powerful radio signal whose passage was noted only by the slight change in tone in the song sung every twelve seconds by the line printer recording that evening’s data.

When the data was analyzed later, an astronomer’s marginal exclamation of the extraordinarily powerful by vanishingly brief blip would give the signal its forever name: the Wow! Signal. How we came to hear this signal, what it could possibly mean, and where it might have come from are all interesting details of an event that left a mystery in its wake, one that citizen scientists are now looking into with a fresh perspective. If it was sent from a region of space with habitable planets, it’s at least worth a listen.Understanding the Wow! Signal requires a look at the instrument that produced it. Affectionately known as “The Big Ear”, the Ohio State University Radio Observatory was the vision of John D. Kraus, a physicist at Ohio State. Dr. Kraus was no stranger to big science — during WWII he developed methods for degaussing naval ships to protect them from magnetically detonated mines, and he worked on a massive cyclotron for the University of Michigan.

Dr. Kraus first described his idea for a telescope capable of detecting extraterrestrial radio signals in an article for Scientific American in 1955. The design of the telescope would be extremely simple, especially compared to the more typical fully steerable dish antenna. It consisted of a large, flat reflector section of steel mesh standing across an open space from a wide, stationary paraboloid reflector. Between these two elements lay a large, flat ground plane area of aluminum-covered pavement. At the focal point of the paraboloid reflector was a small shack containing the feed horns, which could move across the width of the telescope on railroad tracks. Although in general the telescope was static and pointed wherever the Earth’s rotation took it, the feedhorn tracking coupled with adjustments to the tilt of the flat reflector gave some control to which part of the sky was being surveyed.

The Big Ear was big: the flat reflector alone was 33 meters tall and 100 meters wide, and the ground plane stretched 150 meters between the two reflectors. But Dr. Kraus had actually designed a much, much bigger antenna.

His original design called for 600-meter-wide reflectors, but when the National Science Foundation grant came through in 1955 at a paltry $48,000, the design was reduced to what was possible. And even then, a great deal of “sweat equity” went into the construction of the Big Ear, with graduate students learning to weld specifically to build the telescope, and with critical equipment such as the parametric amplifiers needed for the receiver being built at cost by an OSU alumnus.


and from Leif Salvberg
QUOTE
As of October 2020, the WOW! Signal remains the strongest candidate SETI signal. It has been suggested that the signal was produced by hydrogen clouds from Comets 266/P Christensen and P/2008 Y2 (Paris and Davies, 2015). However, this hypothesis has been dismissed by the scientific community, and the source of the signal remains unknown.


Despite the WOW! Signal never repeated, the key aspect was its duration. The signal lasted for 72 seconds, but since this was the maximum amount of time that the Big Ear radio telescope was able to observe, it is likely that the signal would have lasted longer.


The main problem, however, is that the signal never repeated. Follow-up observations of the area conducted by many observatories during several years never detected another signal (Gray and Ellingsen, 2002). Nonetheless, the fact that the signal never repeated, does not necessarily discard that it was produced by extraterrestrial intelligence.


In fact, if we analyse the history of (the few) radio signals that humanity have sent to several targets in the hope of contacting a civilization, none of those transmissions had a long duration or were repeatedly sent for a long time. An extraterrestrial civilization could have opted to behave in a similar manner.


Few attempts have been made to determine the exact location of the WOW! Signal due to the difficulty involved. Despite it was detected in just one of the two feed horns of the radio telescope, the data was processed in a way that does not allow us to determine which of the feed horns actually received the signal.


They are out there all right, but not wanting to get too close to us because of COVID (and Trump)..
Mick



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mullokintyre
post Posted: Nov 23 2020, 08:49 PM
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The mighty winged suits have gone green.
Not satisfied with jet packs, rechargeable elctric packs are now the power source.
BMW has spent the last three years developing an electrified winged suit.

From BMW Winged Suit
QUOTE
Base jumper and wingsuit pilot Peter Salzman, a 33-year-old Austrian, was recently outfitted with the suit and leaped from a helicopter. The 15 kW battery pack, powering two carbon impellers, spinning at 25,000 rpm, allowed Salzman to reach 186 mph.Salzmann's first flight was a wild success. Next, it appears the daredevil wants to fly the wingsuit between skyscrapers.

There's no word if the wingsuit will be commercially available from BMW. Powered wingsuits and jetpacks could be the future of private flight, or perhaps quickly adopted by the military for the modern battlefield. Either way, these alternative forms of flight appear to be maturing in a way that could be commercially available by the midpoint of the decade.


I am still trying to get my head around how the two impellers propel the guy at those speeds, I would have thought that the tips would exceed the speed of sound and lose all effectiveness.
The videos are amazing, Who would have thought that the Swiss have developed a wind tunnel just for testing winged suits!

Mick




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mullokintyre
post Posted: Nov 6 2020, 11:01 AM
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From The Mind Unleashed

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After months of radio silence, NASA has finally reconnected with its Voyager 2 space craft. The Voyager 2 spacecraft has been scouring the cosmos for longer than 40 years, all that time staying in contact with NASA’s team of engineers. However, in March of this year, NASA closed communication with the craft.

The space agency left the shuttle to spend a secluded few months in space without signal to upgrade its communication system. Flying some 11.5 billion miles away from Earth, Voyager 2 was left to its own equipment in mid-March.

But on October 29th right before Halloween, NASA briefly reconnected with Voyager 2 while testing its new Deep Space Network antennas (DSN), NASA reported. Voyager 2 was on an important scientific mission originally to study the outer planets, and now in its extended mission, to study deep Interstellar Space in general.

It’s also one of the furthest manmade objects from Earth. NASA notes that Voyager 2 has left the Solar System entirely. To communicate with the spacecraft, NASA relies on the Deep Space Network antennas (DSN).
The DSN is reliable. But much like the Voyager 2, it’s old, very old. To be more precise, it’s more than 70 years old. To put that into perspective, the system was first created when NASA launched its first satellite, Explorer 1, in 1958. The DSN is used to communicate with an estimated 30 spacecraft every day and it runs 24 hours a day, 365 days a year. As another fun fact, the system is spread out across three joint sites located in the United States, Australia, and Spain.

As NASA prepares for numerous new missions to the moon and mars, all launching in the next few years, the DSN is certainly overdue for a much-needed upgrade to its systems and software.

NASA also started its critical work with an antenna denominated Dss43 that is 230-feet-wide, about the size of a 20-story building, and is located in Canberra, Australia. Dss43 has been operational for 48 years and some of its components, including the conductor used to actively communicate with Voyager 2, have never been given a tune-up. NASA has now drastically improved Dss43’s heating and cooling equipment, power supply equipment, and other devices used to operate. On October 29th, NASA sent a brief call to Voyager 2 to test the new equipment to make sure it was operational.


“What makes this task unique is that we’re doing work at all levels of the antenna, from the pedestal at ground level all the way up to the feedcones at the center of the dish that extend above the rim,” Brad Arnold, the DSN project manager at NASA’s Jet Propulsion Lab in Southern California, said in a statement. “This test communication with Voyager 2 definitely tells us that things are on track with the work we’re doing.”

In the test, NASA’s mission control operators on the ground transmitted a series of commands to Voyager 2, and the spacecraft executed the commands, confirming the test was a success.

NASA is going to cut off its communications to Voyager 2 again until later next year. Dss43 will not be fully back online until February 202, so Voyager 2 will have to endure several more months without communication to ground control, which is worrying for engineers.

“Having the antenna down for one year is not an ideal situation for Voyager or for many other NASA missions,” Philip Baldwin, operations manager for NASA’s Space Communications and Navigation (SCaN) Program, said in a statement. “The agency made the decision to conduct these upgrades to ensure that the antenna can continue to be used for current and future missions. For an antenna that is almost 50 years old, it’s better to be proactive than reactive with critical maintenance.”

Not bad for a bit of old technology.
Wonder just how long it can keep sending stuff back??
This was from the days when NASA did science rather than social engineering.

Mick




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mullokintyre
post Posted: Oct 30 2020, 11:14 AM
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Heres a new twist on the "big Bang".
FromUniversity of Hawaii
QUOTE
University of Hawaiʻi Institute for Astronomy (IfA) astronomer has revealed critical new findings linked to a large asteroid expected to pass extremely close to Earth. Dave Tholen and collaborators have announced the detection of Yarkovsky acceleration on the near-Earth asteroid Apophis. This acceleration arises from an extremely weak force on an object due to non-uniform thermal radiation. This force is particularly important for the asteroid Apophis, as it affects the probability of an Earth impact in 2068.

All asteroids need to reradiate as heat the energy they absorb from sunlight in order to maintain thermal equilibrium, a process that slightly changes the orbit of the asteroid. Prior to the detection of Yarkovsky acceleration on Apophis, astronomers had concluded that a potential impact with Earth in 2068 was impossible. The detection of this effect acting on Apophis means that the 2068 impact scenario is still a possibility.

Apophis is noteworthy because of its extremely close approach to the Earth on Friday, April 13, 2029, when the 300 meter-sized asteroid will become visible to the unaided eye as it passes within the belt of communications satellites orbiting the Earth.

“We have known for some time that an impact with Earth is not possible during the 2029 close approach,” said Tholen, who has been accurately tracking the motion of Apophis in the sky since his team discovered it in 2004. “The new observations we obtained with the Subaru telescope earlier this year were good enough to reveal the Yarkovsky acceleration of Apophis, and they show that the asteroid is drifting away from a purely gravitational orbit by about 170 meters per year, which is enough to keep the 2068 impact scenario in play.”


Doubt if I will be around in '68 to observe the big bang though.
Mick



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mullokintyre
post Posted: Sep 22 2020, 11:08 PM
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And on another front in the "we really don't know much" department.
From NEWSZONE

QUOTE
An oval-shaped area of lower magnetic intensity in the atmosphere between South America and Africa is causing concern to NASA over the potential danger it poses to satellites and spacecraft that pass through it, the website ScienceAlert.com reported.

The South Atlantic Anomaly, first identified in 1958, appears to be dividing into two different cells, one over South America and the other off the coast of South Africa.

The concern is due to the fact the weakened magnetic field results in the closest approach of the Van Allen radiation belts to the Earth's surface. That leaves what some scientists refer to a "pothole" or "dent" in which charged solar particles can sail through the Earth's atmosphere and wreak havoc on electronic components, causing them to short-circuit and malfunction."The observed SAA can be also interpreted as a consequence of weakening dominance of the dipole field in the region," according to geophysicist and mathematician Weijia Kuang at NASA's Goddard Space Flight Center in Greenbelt, Maryland.

"More specifically, a localized field with reversed polarity grows strongly in the SAA region, thus making the field intensity very weak, weaker than that of the surrounding regions."

The consequences are that man-made satellites, such as the International Space Station, must take precautions when their orbits take it through the zone. Some satellite operators must routine shut down their equipment to avoid significant data loss or even permanent damage to key components.

Studies have indicated not only is the zone splitting, it appears to be moving to the northwest.

"Even though the SAA is slow-moving, it is going through some change in morphology, so it's also important that we keep observing it by having continued missions," Goddard geophysicist Terry Sabaka said.

"Because that's what helps us make models and predictions."


Had a bit of a chuckle over that last bit.
Their models and predictions didn't show the anomaly, only by the very basic science principle of observtion ond measurement did it get discovered.

Mick



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triage
post Posted: Sep 22 2020, 06:26 PM
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In Reply To: mullokintyre's post @ Sep 21 2020, 09:13 PM

Thanks Mick, it is a great watch. And more impressive work by Aussie Terry Tao.



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mullokintyre
post Posted: Sep 22 2020, 12:47 PM
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In Reply To: Mork's post @ Sep 22 2020, 10:40 AM

It reinforces to me just how much we really don't know about a lot of things..
Mick



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Mork
post Posted: Sep 22 2020, 10:40 AM
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In Reply To: mullokintyre's post @ Sep 21 2020, 09:13 PM

Nice video,
It brought a chuckle when considering the possibility of the earth flipping becomes a "conspiracy theory"
It's quite interesting to note that the earth has a slow wobble in its rotation axis of about 2%
There's also the story in the bible of the sun coming to a standstill, hieroglyphs in Egypt and ancient myths in China, North & South America describing similar events in pre-history.
Kind of makes you wonder.




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mullokintyre
post Posted: Sep 21 2020, 09:13 PM
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So how many of us are aware of the Dzhanibekov Effect or Tennis Racket Theorem?
here is a video that demonstrates its effect, and goes a good way to explaining why.
Bizarre behaviour of Spinning objects.
Mick



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birnam
post Posted: Sep 18 2020, 10:15 AM
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In Reply To: mullokintyre's post @ Sep 18 2020, 09:43 AM

This research was awarded the Ig Nobel prize for Psychology. May there be more like it.

https://arstechnica.com/science/2020/09/bel...g-nobel-prizes/


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