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PostPosted: Fri Jul 31, 2020 6:58 am
 


***

I've been trying to get a glimpse of Neowise, but between the cloud cover and the constant sunrise/sunset this time of year it's been tough to see.


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PostPosted: Fri Jul 31, 2020 7:02 am
 


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SpaceX completes static fire of Starship prototype, will hop next

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After scrubbing several attempts for weather concerns, technical issues, and even a range violation due to a nearby boat, SpaceX succeeded in static-fire testing the latest prototype of its Starship vehicle on Thursday.

At 3:02pm local time in South Texas, the single Raptor engine attached to the Starship prototype dubbed Serial Number 5, or SN5, roared to life for a few seconds. In video shared by NASASpaceflight.com, the test appeared to be nominal, evidently providing SpaceX engineers with the confidence they need in the latest iteration of Starship.

Starship SN5 just completed full duration static fire. 150m hop soon.

— Elon Musk (@elonmusk) July 30, 2020

Shortly after the test, the founder and chief engineer of SpaceX, Elon Musk, confirmed that the static fire meant the company now plans to move forward with a short test flight of the vehicle. Based upon a notification from the US Federal Aviation Administration, this 150-meter flight test could take place as soon as Sunday, with a launch window opening at 8am local time (13:00 UTC).

This would be the first flight test of Starship hardware since a stubby prototype—Starhopper—soared to 150 meters in late August 2019. That test, in which a single Raptor engine powered the vehicle upward and laterally for about 100 meters before landing, was successful in demonstrating thrust and vector control of the methane-fueled engine.

Since then, SpaceX has built several full-scale prototypes, losing them to a varying array of fueling and pressure tests. With an iterative test program like the one SpaceX is using to develop Starship, the company has chosen to accept some reasonable level of risk in order to move fast.

And SpaceX has been doing just that. Over the last eight months, it has built an impressive factory in South Texas and has begun to churn out Starship prototypes. Its engineers and technicians have reduced the time to build a single Starship down from months to weeks, bringing the company closer to Musk's ultimate goal of mass-producing the large, interplanetary spaceships that may one day allow humans to settle Mars.



https://arstechnica.com/science/2020/07 ... -hop-next/



Note: "SN5" is "Serial Number 5", or the 5th Starship to be tested. The other 4 blew up during their testing.


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PostPosted: Mon Aug 03, 2020 7:14 am
 




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PostPosted: Wed Aug 05, 2020 10:02 am
 




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PostPosted: Wed Aug 05, 2020 7:45 pm
 




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PostPosted: Thu Aug 06, 2020 11:46 am
 


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New Solar Model Successfully Predicted Seven of the Sun’s Last Nine Big Flares


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Since it launched in 2010, the Solar Dynamics Observatory has helped scientists understand how the Sun’s magnetic field is generated and structured, and what causes solar flares. One of the main goals of the mission was to be able to create forecasts for predicting activity on the Sun.

Using mission data from the past 10 years, SDO scientists have now developed a new model that successfully predicted seven of the Sun’s biggest flares from the last solar cycle, out of a set of nine.

The team says that with more development, the model could be used to inform forecasts of these intense bursts of solar radiation, which influence life on Earth and can affect our technological systems.

Led by Kanya Kusano, the director of the Institute for Space-Earth Environmental Research at Japan’s Nagoya University, a team of scientists built a physics-based model, which they call the k-scheme, to predict large solar flares. They based the model on a magnetic map created from SDO’s observations of magnetic fields on the Sun’s surface.

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https://www.universetoday.com/147324/ne ... ig-flares/


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PostPosted: Mon Aug 10, 2020 11:06 am
 


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Dwarf planet closest to Earth is geologically alive



Tucked into the asteroid belt between Mars and Jupiter, the dwarf planet Ceres is a small world that holds big surprises. A slew of new research from NASA’s Dawn spacecraft advances the case that—in its own cold, salty way—Ceres is a geologically active body, with ice volcanoes and surviving pockets of an ancient ocean.

About a year’s worth of data collected by Dawn from late 2017 through late 2018—during its final orbits before running out of fuel—show that the dwarf planet probably has briny liquid seeping out on its surface, as well as mounds and hills that formed when ice melted and refroze after an asteroid impact about 20 million years ago.

The idea that liquid water could persist on Ceres—a world that’s less than a third of the moon’s width—would have once seemed outlandish. But now that humankind has seen it up close, we know that frigid, tiny Ceres is geologically alive.

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https://www.nationalgeographic.com/scie ... nasa-dawn/


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PostPosted: Mon Aug 10, 2020 4:21 pm
 




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PostPosted: Wed Aug 12, 2020 7:40 am
 


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Arecibo Observatory damaged by broken lashing cable


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One of the auxiliary cables that helps support the receiver platform in place above the famous Arecibo Observatory in Puerto Rico broke on Monday, August 10, 2020, causing a 100-foot-long (30-meter-long) gash on the southeast side of the 1,000-foot (305-meter) reflector dish.

According to the University of Central Florida (UFC), which manages the National Science Foundation facility, the three-inch cable also damaged about six to eight panels in the Gregorian Dome, an antenna receiver on the platform. It is not yet clear what caused the cable to break.

There are 18 cables, running from three reinforced concrete towers, which support the 900-ton platform above the dish. The facility is now closed while engineers review the damage and assess the extent of repairs that will be needed to bring the telescope back online. Francisco Cordova, the director of the observatory, said:

We have a team of experts assessing the situation. Our focus is assuring the safety of our staff, protecting the facilities and equipment, and restoring the facility to full operations as soon as possible, so it can continue to assist scientists around the world.



https://earthsky.org/space/arecibo-obse ... hing-cable


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PostPosted: Wed Aug 12, 2020 7:41 am
 


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This is the way the universe ends: not with a whimper, but a bang

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An artist’s impression of a black dwarf, a cooled-down stellar remnant that could form in trillions of years
MARK GARLICK/Science Source


In the unimaginably far future, cold stellar remnants known as black dwarfs will begin to explode in a spectacular series of supernovae, providing the final fireworks of all time. That’s the conclusion of a new study, which posits that the universe will experience one last hurrah before everything goes dark forever.

Astronomers have long contemplated the ultimate end of the cosmos. The known laws of physics suggest that by about 10100 (the No. 1 followed by 100 zeros) years from now, star birth will cease, galaxies will go dark, and even black holes will evaporate through a process known as Hawking radiation, leaving little more than simple subatomic particles and energy. The expansion of space will cool that energy nearly to 0 kelvin, or absolute zero, signaling the heat death of the universe and total entropy.

But while teaching an astrophysics class this spring, theoretical physicist Matt Caplan of Illinois State University realized the fate of one last group of entities had never been accounted for. After exhausting their thermonuclear fuel, low mass stars like the Sun don’t pop off in dramatic supernovae; rather, they slowly shed their outer layers and leave behind a scorching Earth-size core known as a white dwarf.

“They are essentially pans that have been taken off the stove,” Caplan says. “They’re going to cool and cool and cool, basically forever.”

White dwarfs’ crushing gravitational weight is counterbalanced by a force called electron degeneracy pressure. Squeeze electrons together, and the laws of quantum mechanics prevent them from occupying the same state, allowing them to push back and hold up the remnant’s mass.

The particles in a white dwarf stay locked in a crystalline lattice that radiates heat for trillions of years, far longer than the current age of the universe. But eventually, these relics cool off and become a black dwarf.

Because black dwarfs lack energy to drive nuclear reactions, little happens inside them. Fusion requires charged atomic nuclei to overcome a powerful electrostatic repulsion and merge. Yet over long time periods, quantum mechanics allows particles to tunnel through energetic barriers, meaning fusion can still occur, albeit at extremely low rates.

When atoms such as silicon and nickel fuse toward iron, they produce positrons, the antiparticle of an electron. These positrons would ever-so-slowly destroy some of the electrons in a black dwarf’s center and weaken its degeneracy pressure. For stars between roughly 1.2 and 1.4 times the Sun’s mass—about 1% of all stars in the universe today—this weakening would eventually result in a catastrophic gravitational collapse that drives a colossal explosion similar to the supernovae of higher mass stars, Caplan reports this month in the Monthly Notices of the Royal Astronomical Society.

Caplan says the dramatic detonations will begin to occur about 101100 years from now, a number the human brain can scarcely comprehend. The already unfathomable number 10100 is known as a googol, so 101100 would be a googol googol googol googol googol googol googol googol googol googol googol years. The explosions would continue until 1032000 years from now, which would require most of a magazine page to represent in a similar fashion.



https://www.sciencemag.org/news/2020/08 ... imper-bang


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PostPosted: Thu Aug 13, 2020 11:47 am
 


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Hubble finds that Betelgeuse's mysterious dimming is due to a traumatic outburst

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This four-panel graphic illustrates how the southern region of the rapidly evolving, bright red supergiant star B


Recent observations of Betelgeuse have revealed that the star's unexpected and significant dimming periods in late 2019 and early 2020 were most likely caused by the ejection and cooling of dense hot gases, and that the star may be going through another dimming period more than a year early.

Between October and November 2019, Hubble Space Telescope observed dense, heated material moving outward through the star's extended atmosphere at 200,000 miles per hour. The following month, several ground-based telescopes observed a decrease in brightness in Betelgeuse's southern hemisphere, as if something was blocking light in this region of the star. By February 2020, the star had lost more than two-thirds of its brilliance, a dimming visible even to the naked eye, creating buzz that the star might be going supernova. Continued ultraviolet light spectroscopic observations with Hubble provided a timeline for researchers to follow, like breadcrumbs leading back through time to pinpoint the source of the mysterious dimming.

"With Hubble, we had previously observed hot convection cells on the surface of Betelgeuse and in the fall of 2019 we discovered a large amount of dense hot gas moving outwards through Betelgeuse's extended atmosphere. We think this gas cooled down millions of miles outside the star to form the dust that blocked the southern part of the star imaged in January and February," said Andrea Dupree, associate director of the Center for Astrophysics | Harvard & Smithsonian, and lead author on the study. "The material was two to four times more luminous than the star's normal brightness. And then, about a month later the south part of Betelgeuse dimmed conspicuously as the star grew fainter. We think it possible that a dark cloud resulted from the outflow that Hubble detected. Only Hubble gives us this evidence that led up to the dimming."

Image



https://phys.org/news/2020-08-hubble-be ... g-due.html


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PostPosted: Fri Aug 14, 2020 9:19 am
 


An older video, but very explanatory.



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PostPosted: Sun Aug 16, 2020 12:34 am
 


DrCaleb wrote:
Quote:
Arecibo Observatory damaged by broken lashing cable


Image

One of the auxiliary cables that helps support the receiver platform in place above the famous Arecibo Observatory in Puerto Rico broke on Monday, August 10, 2020, causing a 100-foot-long (30-meter-long) gash on the southeast side of the 1,000-foot (305-meter) reflector dish.

According to the University of Central Florida (UFC), which manages the National Science Foundation facility, the three-inch cable also damaged about six to eight panels in the Gregorian Dome, an antenna receiver on the platform. It is not yet clear what caused the cable to break.

There are 18 cables, running from three reinforced concrete towers, which support the 900-ton platform above the dish. The facility is now closed while engineers review the damage and assess the extent of repairs that will be needed to bring the telescope back online. Francisco Cordova, the director of the observatory, said:

We have a team of experts assessing the situation. Our focus is assuring the safety of our staff, protecting the facilities and equipment, and restoring the facility to full operations as soon as possible, so it can continue to assist scientists around the world.



https://earthsky.org/space/arecibo-obse ... hing-cable




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PostPosted: Sun Aug 16, 2020 2:36 pm
 




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PostPosted: Mon Aug 17, 2020 9:44 am
 


Quote:
Planet X? Why not a tiny black hole instead?

Planet X has a long and storied history of non-existence. For about 130 years, astronomers have debated the existence of an additional planet or planets to explain discrepancies in the orbits of the known planets (mainly Neptune and Uranus). Later, the list of discrepancies was expanded to cover trans-Neptunian objects. But none of the Planet X candidates discovered, including Pluto, have the mass or location to explain observations.

Primordial black holes have now been proposed as the latest planet X (or planet 9, since Pluto was demoted).
Orbital weirdness

Planet X’s origin starts with the discovery of Neptune. Neptune was not found by accident: observations of oddities in the orbit of Uranus were used to calculate the location of Neptune, and it was subsequently found.

That is a game that can be played more than once. Astronomers then noted that Uranus and Neptune’s orbits could be better explained by the existence of another large planet. Follow-up observations have found numerous objects: Pluto and Charon, Sedna, and Eris to name a few. None of these far-flung bodies is large enough to be planet X. But some of their orbits may also suggest a new planet is needed.

Some trans-Neptunian objects have very weird orbits. Many are clustered and have highly elliptical orbits, and there is a sub-group that orbits well out of the plane in which the planets orbit. That’s unusual, since the action of gravity and the nature of the disc that formed the planets typically keeps everything close to the same orbital plane. Finding highly inclined orbits suggests that something is pulling the objects back out of the plane.

A planet that is large and far enough from the Sun might explain these orbits. Indeed, researchers have calculated a range of different planet masses and orbits that may account of the behavior of objects like Sedna.

By happy coincidence, the required masses and distances correspond to an observed gravitational lensing anomaly—an excess of events where the gravitational influence of an unseen object distorted the light from distant stars. That is, there is mass out there, and it is unseen. Could this be a new planet?



https://arstechnica.com/science/2020/08 ... e-instead/


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