Starship Asterisk*

[quote="APOD Robot" post_id=340387 time=1721707555 user_id=128559]
[url=https://apod.nasa.gov/apod/ap240723.html] [img]https://apod.nasa.gov/apod/calendar/S_240723.jpg[/img] [size=150]The Crab Nebula from Visible to X-Ray[/size][/url]

[b] Explanation: [/b] What powers the Crab Nebula? A city-sized magnetized [url=https://apod.nasa.gov/apod/ap030201.html]neutron star[/url] spinning around 30 times a second. Known as the [url=https://en.wikipedia.org/wiki/Crab_Pulsar]Crab Pulsar[/url], it is the bright spot in the center of the gaseous swirl at the nebula's core. About 10 light-years across, the [url=https://i.chzbgr.com/full/9047697920/hF7BB9AC7/]spectacular picture[/url] of the [url=https://en.wikipedia.org/wiki/Crab_Nebula]Crab Nebula[/url] (M1) frames a swirling central disk and complex filaments of surrounding and expanding glowing gas. The picture combines [url=https://science.nasa.gov/ems/09_visiblelight/]visible light[/url] from the [url=https://science.nasa.gov/mission/hubble/overview/about-hubble/]Hubble Space Telescope[/url] in red and blue with [url=https://science.nasa.gov/ems/11_xrays/]X-ray light[/url] from the [url=https://chandra.harvard.edu/about/]Chandra X-ray Observatory[/url] shown in white, and diffuse X-ray emission detected by [url=https://www.nasa.gov/ixpe-overview/]Imaging X-ray Polarimetry Explorer[/url] (IXPE) in diffuse purple. The central [url=https://apod.nasa.gov/apod/ap210209.html]pulsar[/url] powers the [url=https://arxiv.org/abs/1704.02968]Crab Nebula[/url]'s emission and [url=https://apod.nasa.gov/apod/ap230320.html]expansion[/url] by slightly slowing its spin rate, which drives out a [url=https://en.wikipedia.org/wiki/Stellar_wind]wind[/url] of energetic [url=https://www.aps.org/archives/publications/apsnews/200010/history.cfm]electrons[/url]. The [url=https://chandra.harvard.edu/photo/2024/25th/more.html" >featured image</a> released today, the <a href="https://chandra.harvard.edu/25th/]25th Anniversary[/url] of the [url=https://youtu.be/al0Ol3rGthE]launch[/url] of NASA's [url=https://en.wikipedia.org/wiki/NASA_large_strategic_science_missions]flagship-class[/url] X-ray Observatory: [url=https://chandra.harvard.edu/]Chandra[/url].


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[/quote]

Judy in the NEW YORK TIMES. Cogratulations!

Out There
Watch These Supernovas Explode Across Time
For the 25th anniversary of the Chandra X-ray Observatory, NASA produced ghostly time-lapse videos of two centuries-old stellar eruptions.
Published July 12, 2024

[url]https://www.nytimes.com/2024/07/12/science/space/chandra-videos-supernova-explosions.html?unlocked_article_code=1.6k0.65Q6.bRjgEbMjyrCI&smid=url-share[/url]

A time-lapse video, assembled from images collected over two decades by the Chandra X-ray Observatory, shows the Crab Nebula, a supernova explosion first observed in 1054.CreditCredit...NASA/CXC/SAO; Image Processing: NASA/CXC/SAO/[b]J. Schmidt[/b], J. Major, A. Jubett, K. Arcand

[quote=Avalon post_id=340406 time=1721787223]
What a spectacular image! I assume there is another jet shooting out on the other side of the disc? What sets that pulsar rotating so incredibly fast?
[/quote]

Conservation of angular momentum. The same thing that speeds up a figure skater when they pull in their arms.

What a spectacular image! I assume there is another jet shooting out on the other side of the disc? What sets that pulsar rotating so incredibly fast?

If only Lord Rosse could see modern images of the "crab" he first drew in the 19th century!
[attachment=1]LR.jpg[/attachment]

[attachment=0]Crab_MultiChandra_960.jpg[/attachment]
What a baffling object…

[quote=Bird_Man post_id=340398 time=1721759653 user_id=141078]
[quote=Ann post_id=340389 time=1721715463 user_id=129702]
[img3="The Crab Nebula from Visible to X-Ray
Image Credit: NASA, ESA, ASI, Hubble, Chandra, IXPE"]https://apod.nasa.gov/apod/image/2407/Crab_MultiChandra_960.jpg[/img3]




Anyway, NASA had better make good use of the Chandra X-ray Telescope now before they retire it. It is such a shame that Chandra will be decommissioned, because the telescope has performed extremely well, has shown no great signs of aging, and is the best X-ray telescope in existence anywhere, unless I am mistaken.

Ann
[/quote]

Ann makes a good point and apparently isn't the only astronomer that thinks it's important to save the Chandra X-ray Telescope. Here is an interesting NPR article on the topic: https://www.npr.org/2024/07/23/nx-s1-5048828/chandra-x-ray-observatory-nasa-powerful-telescope-anniversary
[/quote]

Agreed. I can't believe that such a mundane thing as a limited budget is the problem here (though, yes, even NASA has to contend with the earthly realm every now and then). You'd think that at least [i][b]ONE [/b][/i]so-called "tech billionaire" would come to the rescue and donate funds.

[quote=Ann post_id=340389 time=1721715463 user_id=129702]
[img3="The Crab Nebula from Visible to X-Ray
Image Credit: NASA, ESA, ASI, Hubble, Chandra, IXPE"]https://apod.nasa.gov/apod/image/2407/Crab_MultiChandra_960.jpg[/img3]




Anyway, NASA had better make good use of the Chandra X-ray Telescope now before they retire it. It is such a shame that Chandra will be decommissioned, because the telescope has performed extremely well, has shown no great signs of aging, and is the best X-ray telescope in existence anywhere, unless I am mistaken.

Ann
[/quote]

Ann makes a good point and apparently isn't the only astronomer that thinks it's important to save the Chandra X-ray Telescope. Here is an interesting NPR article on the topic: https://www.npr.org/2024/07/23/nx-s1-5048828/chandra-x-ray-observatory-nasa-powerful-telescope-anniversary

[quote="Sa Ji Tario" post_id=340395 time=1721745837]
[quote=Roy post_id=340394 time=1721743868 user_id=1]
Looks like two annular rings with a jet or ejection down from the center.
Anyway, we can calculate the average expansion velocity of the nebula - given a diameter of 10 ly, radius of 5 ly, 946 years from first observed to image referenced for Hubble visible light (2000 - 1054) = 1585 kilometers per second. Enormous amount of energy released to start that off.
[/quote]
There are stars that generate winds of 2,000-3,000 k/s
[/quote]

Yes, but (kinetic) energy is proportional to mass and velocity squared. The important point here is mass. The total mass that is moving here is many orders of magnitude greater than the mass of any stellar wind.

[quote=Roy post_id=340394 time=1721743868 user_id=1]
Looks like two annular rings with a jet or ejection down from the center.
Anyway, we can calculate the average expansion velocity of the nebula - given a diameter of 10 ly, radius of 5 ly, 946 years from first observed to image referenced for Hubble visible light (2000 - 1054) = 1585 kilometers per second. Enormous amount of energy released to start that off.
[/quote]
There are stars that generate winds of 2,000-3,000 k/s

Looks like two annular rings with a jet or ejection down from the center.
Anyway, we can calculate the average expansion velocity of the nebula - given a diameter of 10 ly, radius of 5 ly, 946 years from first observed to image referenced for Hubble visible light (2000 - 1054) = 1585 kilometers per second. Enormous amount of energy released to start that off.

[img3="The Crab Nebula from Visible to X-Ray
Image Credit: NASA, ESA, ASI, Hubble, Chandra, IXPE"]https://apod.nasa.gov/apod/image/2407/Crab_MultiChandra_960.jpg[/img3]


I wasn't aware that the disk surrounding the central neutron star was so relatively large. If the entire Crab Nebula is 10 light-years across, then I guess that the swirling disk must be at least 2 light-years in diameter. Halfway to Proxima Centauri!

Anyway, NASA had better make good use of the Chandra X-ray Telescope now before they retire it. It is such a shame that Chandra will be decommissioned, because the telescope has performed extremely well, has shown no great signs of aging, and is the best X-ray telescope in existence anywhere, unless I am mistaken.

Ann

[url=https://apod.nasa.gov/apod/ap240723.html] [img]https://apod.nasa.gov/apod/calendar/S_240723.jpg[/img] [size=150]The Crab Nebula from Visible to X-Ray[/size][/url]

[b] Explanation: [/b] What powers the Crab Nebula? A city-sized magnetized [url=https://apod.nasa.gov/apod/ap030201.html]neutron star[/url] spinning around 30 times a second. Known as the [url=https://en.wikipedia.org/wiki/Crab_Pulsar]Crab Pulsar[/url], it is the bright spot in the center of the gaseous swirl at the nebula's core. About 10 light-years across, the [url=https://i.chzbgr.com/full/9047697920/hF7BB9AC7/]spectacular picture[/url] of the [url=https://en.wikipedia.org/wiki/Crab_Nebula]Crab Nebula[/url] (M1) frames a swirling central disk and complex filaments of surrounding and expanding glowing gas. The picture combines [url=https://science.nasa.gov/ems/09_visiblelight/]visible light[/url] from the [url=https://science.nasa.gov/mission/hubble/overview/about-hubble/]Hubble Space Telescope[/url] in red and blue with [url=https://science.nasa.gov/ems/11_xrays/]X-ray light[/url] from the [url=https://chandra.harvard.edu/about/]Chandra X-ray Observatory[/url] shown in white, and diffuse X-ray emission detected by [url=https://www.nasa.gov/ixpe-overview/]Imaging X-ray Polarimetry Explorer[/url] (IXPE) in diffuse purple. The central [url=https://apod.nasa.gov/apod/ap210209.html]pulsar[/url] powers the [url=https://arxiv.org/abs/1704.02968]Crab Nebula[/url]'s emission and [url=https://apod.nasa.gov/apod/ap230320.html]expansion[/url] by slightly slowing its spin rate, which drives out a [url=https://en.wikipedia.org/wiki/Stellar_wind]wind[/url] of energetic [url=https://www.aps.org/archives/publications/apsnews/200010/history.cfm]electrons[/url]. The [url=https://chandra.harvard.edu/photo/2024/25th/more.html" >featured image</a> released today, the <a href="https://chandra.harvard.edu/25th/]25th Anniversary[/url] of the [url=https://youtu.be/al0Ol3rGthE]launch[/url] of NASA's [url=https://en.wikipedia.org/wiki/NASA_large_strategic_science_missions]flagship-class[/url] X-ray Observatory: [url=https://chandra.harvard.edu/]Chandra[/url].


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