Author Topic: Astronomy Corner  (Read 28405 times)

Svetz

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Re: Astronomy Corner
« Reply #240 on: July 15, 2018, 04:40:34 am »
Dark flow (a mysterious non-random component of the peculiar velocity of galaxy clusters, not to be confused with dark energy, dark matter, or dark fluid) has been traced to deeper outside our visible universe: https://www.nasa.gov/centers/goddard/news/releases/2010/10-023.html

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"This is not something we set out to find, but we cannot make it go away," Kashlinsky said. "Now we see that it persists to much greater distances"

Svetz

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Svetz

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Re: Astronomy Corner
« Reply #242 on: September 23, 2018, 09:10:07 am »
Images are starting to come back from Japanese rovers on Asteroid Ryugu:

https://www.geekwire.com/2018/japanese-mini-rovers-send-back-first-images-hop-around-asteroid/


Svetz

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Solar Minimum cooling the upper atmosphere
« Reply #243 on: September 28, 2018, 10:54:33 am »
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THE CHILL OF SOLAR MINIMUM: The sun is entering one of the deepest Solar Minima of the Space Age. Sunspots have been absent for most of 2018, and the sun's ultraviolet output has sharply dropped. New research shows that Earth's upper atmosphere is responding.

"We see a cooling trend," says Martin Mlynczak of NASA's Langley Research Center. "High above Earth's surface near the edge of space, our atmosphere is losing heat energy. If current trends continue, the upper atmosphere could soon set a Space Age record for cold.

These results come from the SABER instrument onboard NASA's TIMED satellite. SABER monitors infrared emissions from carbon dioxide (CO2) and nitric oxide (NO), two substances that play a key role in the energy balance of air 100 to 300 kilometers above our planet's surface. By measuring the infrared glow of these molecules, SABER can assess the thermal state of gas at the very top of the atmosphere-a layer researchers call "the thermosphere."

"The thermosphere always cools off during Solar Minimum. It's one of the most important ways the 11-year solar cycle affects our planet," explains Mlynczak, the associate principal investigator for SABER."




The above is from http://spaceweather.com/, but since it changes frequently the source is: https://www.sciencedirect.com/science/article/pii/S1364682618301354?via%3Dihub

Svetz

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Earth missed a Carrington Event in 2012
« Reply #244 on: September 28, 2018, 11:05:26 am »
A paper referenced in the article below predicts a 12% chance to get hit by a Carrington event in the next 10 years.  The problem with being supremely lucky over the last 150 years is that without a disaster we don't really have all the infrastructure in place to deal with a storm that knocks out power/water/transportation/communication (cell, TV, Radio)/refrigeration/fuel/GPS world wide (although in 2017 Congress did order some stockpiling and FEMA does have a plan).  If it were big enough, it would be like a zombie apocolypse minus the zombies (don't worry, we'd have to be pretty unlucky for it to be so big that power to major cities couldn't be restored in a few days).  We also have warning systems, so you (and the power company) could in advance disconnect/unplug/open breakers (important since it's not just protecting delicate electronics... it's also keeping things from catching fire).

From: https://science.nasa.gov/science-news/science-at-nasa/2014/23jul_superstorm

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If an asteroid big enough to knock modern civilization back to the 18th century appeared out of deep space and buzzed the Earth-Moon system, the near-miss would be instant worldwide headline news.

A few years ago, Earth experienced a close shave just as perilous, but most newspapers didn't mention it. The "impactor" was an extreme solar storm, the most powerful in as much as 150+ years.

"If it had hit, we would still be picking up the pieces," says Daniel Baker of the University of Colorado.

Baker, along with colleagues from NASA and other universities, published a seminal study of the storm in the December 2013 issue of the journal Space Weather.  Their paper, entitled "A major solar eruptive event in July 2012," describes how a powerful coronal mass ejection (CME) tore through Earth orbit on July 23, 2012.  Fortunately Earth wasn't there. 

« Last Edit: September 28, 2018, 11:31:46 am by Svetz »

Svetz

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Re: Astronomy Corner
« Reply #245 on: September 29, 2018, 09:06:44 am »
Details on the Ryugu rovers: https://www.youtube.com/watch?v=l0zKdl7vdZM

Svetz

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Kessler Syndrome Tipping Point: Are we there yet?
« Reply #246 on: October 09, 2018, 03:58:01 am »
The premise behind the "kessler syndrome" is that Earth orbit gets more dangerous as the amount of debris increases.
As more impacts occur, more debris is generated - like a runaway nuclear reaction.
Eventually, there's so much debris that all satelites (and your way of life) are destroyed and it's impossible to launch anything new.

Nice overview here:  https://www.youtube.com/watch?v=OA9RqYAsQ1A

Makes you wonder as many countries and private organizations are launching more and more into orbit.

NASA Low Earth Orbit image based on items they track:

Svetz

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End of Hubble?
« Reply #247 on: October 10, 2018, 02:57:37 am »
Hubble lost a gyro last friday and entered safe mode, it may not be recoverable. 

The good news is they might know why reaction wheels fail so frequently in space, the idea is that solar events cause electrostatic discharge across the ball bearing causing degradation; if so it's pretty easy to fix so possibly future satellites will last longer.

details: https://www.youtube.com/watch?time_continue=5&v=KibT-PEMHUU

Svetz

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Oumuamua
« Reply #248 on: November 06, 2018, 08:03:23 am »
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Cigar-shaped interstellar object may have been an alien probe, Harvard paper claims
Full Story: https://www.cnn.com/2018/11/06/health/oumuamua-alien-probe-harvard-intl/index.html


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On its way out of the Solar System, something unexpected happened. 'Oumuamua accelerated as if jets of gas were pushing it forward.

https://www.youtube.com/watch?v=PYxhxUik5PY
« Last Edit: November 06, 2018, 09:15:50 am by Svetz »

Svetz

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Re: Astronomy Corner
« Reply #249 on: November 06, 2018, 08:10:54 am »
https://www.technologyreview.com/s/418011/orange-dwarf-star-set-to-smash-into-the-solar-system/

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Gliese 710 has the potential to perturb the hypothetical Oort cloud in the outer Solar System, exerting enough force to send showers of comets into the inner Solar System for millions of years, triggering visibility of about ten naked-eye comets per year,[12] and possibly causing an impact event. According to Filip Berski and Piotr Dybczyński, this event will be "the strongest disrupting encounter in the future and history of the solar system"

Only a million years to wait.  ;-)

Svetz

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China's moon mission launches 12/8
« Reply #250 on: December 07, 2018, 07:23:51 am »
Chang'e 4 (CE-4) lander and rover mission on the far side of the Moon. Should land on 12/31.

Svetz

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Re: Astronomy Corner
« Reply #251 on: December 07, 2018, 07:25:57 am »
The SpaceX mission was successful, sort of... the hydraulics on a grid fin failed.  Amazingly the rocket self corrected.  If it hadn't landed in a swamp it might have stayed upright.  Nice review here: https://www.youtube.com/watch?v=wNpDWSfSd8k

Pharyu

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Re: Astronomy Corner
« Reply #252 on: December 10, 2018, 01:11:31 pm »
The SpaceX mission was successful, sort of... the hydraulics on a grid fin failed.  Amazingly the rocket self corrected.  If it hadn't landed in a swamp it might have stayed upright.  Nice review here: https://www.youtube.com/watch?v=wNpDWSfSd8k


Still soft landed in the water, and was able to purge its fuel tank. So they can actually recover and find out what caused the failure.


Svetz

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