Scientists Calculate the Pressure Inside a Proton and It's Higher Than in a Neutron Star - Canadanewsmedia
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Scientists Calculate the Pressure Inside a Proton and It's Higher Than in a Neutron Star

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This is not at all how you would measure the pressure inside of a proton.
Illustration: Department of Energy/Jefferson Lab

The pressure inside the particles that make up every atom in the universe could be greater than the pressure inside the densest stars, according to a new measurement.

Scientists at Jefferson Lab in Virginia calculated the pressure using the lab’s Continuous Electron Beam Accelerator Facility, or CEBAF, and some tricky mathematics. The measurement will mainly be useful for fundamentally understanding these particles’ nature. The calculation is pretty mind-boggling.

“Neutron stars are some of the densest objects we know of in the universe,” Volker Burkert, Jefferson Lab Hall B leader, told Gizmodo. “It’s an order of magnitude bigger than that. It could be the record observation of a pressure on Earth.”

The researchers calculated the pressure faced by the quarks that make up protons at 1035 pascals, equalling 1030 times the pressure at sea level, according to the paper published in Nature.

Ascertaining that pressure required a series of mathematical steps, beginning with another innate set of properties of the proton, called its gravitational form factors. These form factors get their name because they can only be directly measured by protons interacting with gravitons. Scientists have never observed a graviton, but two photons can serve as a proxy.

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The CEBAF measures the values by shooting electrons at protons in liquid hydrogen, resulting in an electron, a proton, and those two photons. Rather than collide with the entire proton, the electrons in the experiment collide with individual quarks through a process called “deeply virtual Compton scattering.” These already-published measurements provided the gravitational form factors needed to calculate the pressure. 

So, what do you do with knowledge of the proton’s ridiculously high internal pressure? First, it’s interesting to know more about perhaps the most important particle to life, since without protons, there would be no atoms and no humans. And there’s still lots to know about protons: Just last week, another team at the Jefferson Lab measured a fundamental property of the proton, called its weak charge, for the first time.

Aside from that, scientists measure two different values for the proton’s radius based on the experiments they perform. It’s a frustrating inconsistency when it comes to understanding a property as basic as a particle’s size. This latest research could offer a new way to measure the proton’s radius based on how the pressure is distributed inside the particle, explained study author and Jefferson Lab physicist Francois-Xavier Girod. It can also motivate theorists to try to understand the very nature of the proton, things like why it doesn’t decay the way a neutron does.

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And things go even deeper than that: Quarks, the smaller pieces that make up protons and neutrons, can never exist on their own—they’re always “confined.” The pressure faced by quarks inside the proton illustrates their permanently social behavior, and could perhaps provide a fundamental mechanism for this so-called quark confinement, said Mu-Chun Chen, a professor of physics and astronomy at the University of California, Irvine, who was not involved with the study.

More precise experiments to measure further properties of the proton are on the horizon, which would reduce some of the uncertainty currently faced by the researchers. But it’s worth appreciating that it takes a lot of effort to keep together the things that, well, keep you together.

[Nature]

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Six Things About NASA's Opportunity Rover Recovery Efforts, Silent Since June 10

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[unable to retrieve full-text content]

  1. Six Things About NASA’s Opportunity Rover Recovery Efforts, Silent Since June 10  SpaceCoastDaily.com
  2. Curiosity finds strange object on the surface of Mars  EarthSky
  3. Curiosity Rover Found A Strange Object On The Surface Of Mars That Puzzled The Scientists  Health Thoroughfare
  4. Full coverage



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Astronomers observe cosmic steam jets and molecules galore

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Illustration highlighting ALMA’s high-frequency observing capabilities. Credit: NRAO/AUI/NSF, S. Dagnello

A team of scientists using the highest-frequency capabilities of the Atacama Large Millimeter/submillimeter Array (ALMA) has uncovered jets of warm water vapor streaming away from a newly forming star. The researchers also detected the “fingerprints” of an astonishing assortment of molecules near this stellar nursery.

The ALMA telescope in Chile has transformed how we see the universe, showing us otherwise invisible parts of the cosmos. This array of incredibly precise antennas studies a comparatively high-frequency sliver of radio light: waves that range from a few tenths of a millimeter to several millimeters in length. Recently, scientists pushed ALMA to its limits, harnessing the array’s highest-frequency (shortest wavelength) capabilities, which peer into a part of the electromagnetic spectrum that straddles the line between infrared light and radio waves.

“High-frequency radio observations like these are normally not possible from the ground,” said Brett McGuire, a chemist at the National Radio Astronomy Observatory in Charlottesville, Virginia, and lead author on a paper appearing in the Astrophysical Journal Letters. “They require the extreme precision and sensitivity of ALMA, along with some of the driest and most stable atmospheric conditions that can be found on Earth.”

Under ideal atmospheric conditions, which occurred on the evening of 5 April 2018, astronomers trained ALMA’s highest-frequency, submillimeter vision on a curious region of the Cat’s Paw Nebula (also known as NGC 6334I), a star-forming complex located about 4,300 light-years from Earth in the direction of the southern constellation Scorpius.

Previous ALMA observations of this region at lower frequencies uncovered turbulent star formation, a highly dynamic environment, and a wealth of molecules inside the nebula.

To observe at higher frequencies, the ALMA antennas are designed to accommodate a series of “bands” — numbered 1 to 10 — that each study a particular sliver of the spectrum. The Band 10 receivers observe at the highest frequency (shortest wavelengths) of any of the ALMA instruments, covering wavelengths from 0.3 to 0.4 millimeters (787 to 950 gigahertz), which is also considered to be long-wavelength infrared light.

These first-of-their-kind ALMA observations with Band 10 produced two exciting results.

Composite ALMA image of NGC 6334I, a star-forming region in the Cat’s Paw Nebula, taken with the Band 10 receivers, ALMA’s highest-frequency vision. The blue component is heavy water (HDO) streaming away from either a single protostar or a small cluster of protostars. The orange region is the “continuum emission” in the same region, which scientists found is extraordinarily rich in molecular fingerprints, including glycolaldehyde , the simplest sugar-related molecule. Credit: ALMA (ESO/NAOJ/NRAO): NRAO/AUI/NSF, B. Saxton

Jets of Steam from Protostar

One of ALMA’s first Band 10 results was also one of the most challenging, the direct observation of jets of water vapor streaming away from one of the massive protostars in the region. ALMA was able to detect the submillimeter-wavelength light naturally emitted by heavy water (water molecules made up of oxygen, hydrogen and deuterium atoms, which are hydrogen atoms with a proton and a neutron in their nucleus).

“Normally, we wouldn’t be able to directly see this particular signal at all from the ground,” said Crystal Brogan, an astronomer at the NRAO and co-author on the paper. “Earth’s atmosphere, even at remarkably arid places, still contains enough water vapor to completely overwhelm this signal from any cosmic source. During exceptionally pristine conditions in the high Atacama Desert, however, ALMA can in fact detect that signal. This is something no other telescope on Earth can achieve.”

As stars begin to form out of massive clouds of dust and gas, the material surrounding the star falls onto the mass at the center. A portion of this material, however, is propelled away from the growing protostar as a pair of jets, which carry away gas and molecules, including water.

The heavy water the researchers observed is flowing away from either a single protostar or a small cluster of protostars. These jets are oriented differently from what appear to be much larger and potentially more-mature jets emanating from the same region. The astronomers speculate that the heavy-water jets seen by ALMA are relatively recent features just beginning to move out into the surrounding nebula.

These observations also show that in the regions where this water is slamming into the surrounding gas, low-frequency water masers – naturally occurring microwave versions of lasers — flare up. The masers were detected in complementary observations by the National Science Foundation’s Very Large Array.

ALMA Observes Molecules Galore

In addition to making striking images of objects in space, ALMA is also a supremely sensitive cosmic chemical sensor. As molecules tumble and vibrate in space, they naturally emit light at specific wavelengths, which appear as spikes and dips on a spectrum. All of ALMA’s receiver bands can detect these unique spectral fingerprints, but those lines at the highest frequencies offer unique insight into lighter, important chemicals, like heavy water. They also provide the ability to see signals from complex, warm molecules, which have weaker spectral lines at lower frequencies.

Using Band 10, the researchers were able to observe a region of the spectrum that is extraordinarily rich in molecular fingerprints, including glycolaldehyde , the simplest sugar-related molecule.

When compared to previous best-in-the-world observations of the same source with the European Space Agency’s Herschel Space Observatory, the ALMA observations detected more than ten times as many spectral lines.

“We detected a wealth of complex organic molecules surrounding this massive star-forming region,” said McGuire. “These results have been received with excitement by the astronomical community and show once again how ALMA will reshape our understanding of the universe.”

ALMA is able to take advantage of these rare windows of opportunity when the atmospheric conditions are “just right” by using dynamic scheduling. That means, the telescope operators and astronomers carefully monitor the weather and conduct those planned observations that best fit the prevailing conditions.

“There certainly are quite a few conditions that have to be met to conduct a successful observation using Band 10,” concluded Brogan. “But these new ALMA results demonstrate just how important these observations can be.”

“To remain at the forefront of discovery, observatories must continuously innovate to drive the leading edge of what astronomy can accomplish,” said Joe Pesce, the program director for the National Radio Astronomy Observatory at NSF. “That is a core element of NSF’s NRAO, and its ALMA telescope, and this discovery pushes the limit of what is possible through ground-based astronomy.”

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August 2018 Mars Bright and Large but Low in the Sky

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by Pat Browne

Recently, a Night Sky Friend recently wrote me to me…:

Looking at Mars lately and wondering if you have already or are intending to open up the telescope for a look at that….

The path of the planets on our summer 2018 southern horizon. Mars, (and Saturn and Jupiter) during the month of August. Mars is bright because it is right after opposition … The summer ecliptic (the path of the planets) is however low. – image courtesy Stellarium

Mars has just passed its closest approach to Earth (July 31 2018) . It is the very bright orangey planet (much brighter than a star) in the low southeast, rising after Jupiter and Satun. It has also just passed the point of  opposition. See https://millstonenews.com/2014/04/night-sky-course-planets-earth-and-orbits-around-the-sun.html

  • The best times to view an outer planet is in the opposition configuration which happens whenever the outer planet lines up with Earth away from the Sun’s glare .
  • The best oppositions are those in which the planet is close to the earth (measured in A.U.s- the distance between the Earth and the Sun) This is seen in the diagram below where the distance between Mars and Earth in late July 2018 is just 0.39 A.U.s
image courtesy https://medium.com/@starwalk/mars-mania-means-opposition-closest-approach-and-a-thunder-moon-meet-up-57d59e05756

This year, 2018, the Mars apparition is similar to the one in 2003 known as the ‘Super-Mars’. Every 15 years or so, the geometry works out that we pass Mars while we are near aphelion (the farthest distance from the sun) and Mars is near perihelion (its closest distance from the sun). When that happens, our two planets are at their minimum distance from one another. When Earth passes a more distantly orbiting planet on the “inside track”, that planet appears in our sky opposite to the sun, … That planet will rise in the east as the sun sets in the west. And because we are closer to it, it will shine brighter than at any other date and look larger in binoculars or a telescope.[courtesy Mars Mania means Opposition…

Earth is on the faster inside track around the Sun. Mars orbit takes almost twice as long. For a bright close up view of Mars, it happens when Mars is at perihelion. As it turns out (no pun intended), Earth happens to be at aphelion, but the distance between the two is at a minimum.

Why is Mars so low when we see it  near opposition in the Northern Hemisphere?

Mars is bright and close, but for observers in the Northern Hemisphere, this event happens in the summer . Since Mars has to be opposite the Sun for opposition; conditions are such that

  • In the Northern hemisphere, during the summer season, the  Sun is high in the sky, that means that…
  •  Planets visible in the night sky in the summer at northern latitudes are low in the sky when they transit.  These planets are away from the glare of the Sun – so opposite the Sun – Sun achieves a high altitude in Summer, planets visible in the northern hemisphere at night have a low altitude. Celestial objects are best viewed high in the sky so that we don’t have to look through a lot of humid atmosphere to observe them.
  • Observers in the Southern Hemisphere have a much higher, clearer view of Mars at this time.

Mars – The previous Super-Mars opposition in 2003

Recall that 2003 was the summer of the “Super-Mars” opposition, and a legendary bad-astronomy fake ‘fact’ found its way into the media. People read that Mars would be “the size of the  moon”. In fact, this is probably due to a mis-quoting of the astronomy column in the Old Farmer’s Almanac written by Bob Berman. Bob confesses:

Not that Mars is immune to hype. In August 2003, we had the closest martian visit in more than 50,000 years, and in the Old Farmer’s Almanac, where [Bob Berman has] been the astronomy editor since forever, I wrote that through any telescope at a mere 100x Mars would look bigger than the naked eye Moon… The fake “Mars is bigger than the Moon” business every single summer stems from that Old Farmer’s Almanac article, with the part about “through the telescope” omitted. [courtesy Astronomy Magazine, August 2008, p. 12).

Observing Mars when it’s disk is largest

So what does this mean…that Mars at a perihelion opposition will appear to be 1/2 degree in a telescope when viewed through a telescope with 100x magnification?

RASC Observer’s Handbook showing apparent size of the martian disk near opposition. July-August 2018 line (opposition) shows 0.38 AU with apparent size 24.3″ (not shown)

Consider how Mars might look in a telescope when its disk is the largest)and compare this to just looking up (without a telescope) to see the Moon when a large portion is lit.

  • Mars at 2018 opposition had an apparent size of 24.4″ (arc-seconds). When we look at Mars through a telescope with an eyepiece providing 100x magnification, that makes it 2440 arc secs (24.4) secs or slightly less than 1/2 degree.
  • Moon waxing/waning Full: When we look up at the sky, naked eye, the Moon takes up less than a degree over the entire sky.

Recently I went out, and tested this perception. I used  a 100x eyepiece for my scope; For a  Pentax XL eyepiece http://www.nightskyinfo.com/eyepieces/#4 the apparent field of view is around 65 degrees. I could count maybe 30 mars diameters on either side of the image; so the apparent size of the disk in the eyepiece was approaching around degree: 65 deg / 60 (mars diameters). Still very small in the eyepiece but not as small as a point source like a star.

Naked Eye Observing  – measuring angles in the Sky

When I hold my arm at arm’s length and extend my pinky finger out to the disk of the moon, the finger covers the moon . The moon has an angular measure of 1/2 degree, or 30 seconds of arc. Hold your pinky out over the moon and it will block it from your field of view. These hand measurements help you approximate angular measures in the sky when you are star-gazing with the naked-eye.

– courtesy One Minute Astronomer measuring distances in the Sky: https://oneminuteastronomer.com/860/measuring-sky/

Observing Mars through a Telescope

Mars, unlike Saturn and Jupiter, is very difficult to observe when it comes to seeing features and detail on the planet. It requires patience and repeated viewing to confirm that you have seen what is shown in, for example, the Mars Profiler provided by Sky and Telescope: https://www.skyandtelescope.com/wp-content/plugins/observing-tools/mars_profiler/mars.html

At 100x I was unable to see these features. It simply looked like an orange disk with perhaps a hint of a darker shade running across the central portion – perhaps Syrtis Major. I suspect that it takes much higher power and large aperture to tease out any features on Mars.

Perhaps that’s why it’s important to try and observe it when the diameter of the disk is near maximum. Try to observe it soon: because our interplanetary distance increases dramatically through September and October, reducing the elusive portrait of the planet to a disk diameter of 11 ” by the end of October.

One can simply enjoy the colour and the brilliance of Mars night after night, with the naked eye, as it retrogrades its way (moving West to East every night)  along the low-slung ecliptic.

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