APOD: The Multiwavelength Crab (2017 May 11)

[APOD Robot]

The Multiwavelength Crab

Explanation: The Crab Nebula is cataloged as M1, the first object on Charles Messier's famous list of things which are not comets. In fact, the Crab is now known to be a supernova remnant, expanding debris from massive star's death explosion, witnessed on planet Earth in 1054 AD. This brave new image offers a 21st century view of the Crab Nebula by presenting image data from across the electromagnetic spectrum as wavelengths of visible light. From space, Chandra (X-ray) XMM-Newton (ultraviolet), Hubble (visible), and Spitzer (infrared), data are in purple, blue, green, and yellow hues. From the ground, Very Large Array radio wavelength data is in shown in red. One of the most exotic objects known to modern astronomers, the Crab Pulsar, a neutron star spinning 30 times a second, is the bright spot near picture center. Like a cosmic dynamo, this collapsed remnant of the stellar core powers the Crab's emission across the electromagnetic spectrum. Spanning about 12 light-years, the Crab Nebula is 6,500 light-years away in the constellation Taurus.

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[bystander]

Crab Nebula in Multiple Wavelengths - Annotated
Video Credit: NASA, ESA, and J. DePasquale (STScI)

This video starts with a composite image of the Crab Nebula, a supernova remnant, that was assembled by combining data from five telescopes spanning nearly the entire breadth of the electromagnetic spectrum: the Very Large Array, the Spitzer Space Telescope, the Hubble Space Telescope, the XMM-Newton Observatory, and the Chandra X-ray Observatory.

The video dissolves to the red-colored radio-light view that shows how a neutron star’s fierce “wind” of charged particles from the central neutron star energized the nebula, causing it to emit the radio waves. The yellow-colored infrared image includes the glow of dust particles absorbing ultraviolet and visible light. The green-colored Hubble visible-light image offers a very sharp view of hot filamentary structures that permeate this nebula. The blue-colored ultraviolet image and the purple-colored X-ray image shows the effect of an energetic cloud of electrons driven by a rapidly rotating neutron star at the center of the nebula.

The Crab Nebula, the result of a supernova explosion seen by Chinese and other astronomers in the year 1054, is 6,500 light-years from Earth.

viewtopic.php?t=37167

[RedFishBlueFish]

1054 AD

Really?

Such usage In this Common Era year of 2017 seems divisive, awkward and not well suited to a diverse audience of those who share an interest in science.

If the desire is to be specifically exclusionary and deliberately sectarian, why use the more politically correct truncated version and not simply have the courage to use the original Anno Domini nostri Jesu Christi?

On the other hand, one might express the year as 1054 CE, as is common in the non-sectarian and inclusive world of science.

[neufer]

1054 AD Really? Such usage In this Common Era year of 2017 seems divisive, awkward and not well suited to a diverse audience of those who share an interest in science.

The Meigetsuki, by Fujiwara no Teika [Sadaie], states:

Tenki reign period of Emperor Go-Reizei, secondyear, fourth lunar month, after the middle ten-day period (zhongxun yihou). At the (double) hour of chou (1-3 am), a guest star appeared in the degrees of (the lunar lodges) Zui (xi) and Shen. It was seen inthe eastern direction and emerged [bo] at the star Tianguan. It was as large as Jupiter.

[Chris Peterson]

If the desire is to be specifically exclusionary and deliberately sectarian, why use the more politically correct truncated version and not simply have the courage to use the original Anno Domini nostri Jesu Christi?

On the other hand, one might express the year as 1054 CE, as is common in the non-sectarian and inclusive world of science.

Certainly it would be better to use CE, and that would be consistent with scholarly usage (which this site should appropriately use). But the use of AD is sufficiently common and normalized in our culture that it no more represents a religious sentiment than "goodbye" or "bless you" in response to a sneeze.

[neufer]

If the desire is to be specifically exclusionary and deliberately sectarian, why use the more politically correct truncated version and not simply have the courage to use the original Anno Domini nostri Jesu Christi? On the other hand, one might express the year as 1054 CE, as is common in the non-sectarian and inclusive world of science.

Certainly it would be better to use CE, and that would be consistent with scholarly usage (which this site should appropriately use). But the use of AD is sufficiently common and normalized in our culture that it no more represents a religious sentiment than "goodbye" or "bless you" in response to a sneeze.

good-bye (interj.) salutation in parting, also goodbye, good bye, good-by, 1590s, from godbwye (1570s), a contraction of God be with ye (late 14c.), influenced by good day, good evening, etc. As a noun from 1570s. Intermediate forms in 16c. include God be wy you, God b'uy, God buoye, God buy, etc.

adieu (interj.) late 14c., adewe, from Old French a Dieu, a Deu, shortened from phrases such as a dieu (vous) commant "I commend (you) to God," from a "to" (see ad-) + dieu "God," from Latin deum, accusative of deus "god," from PIE *deiwos "god" (from root *dyeu- "to shine," in derivatives "sky, heaven, god"). Originally said to the party left (farewell was to the party setting forth), but in English used as a general parting salutation.

<<In George Orwell's world of Nineteen Eighty-Four, Newspeak is a controlled language, of restricted grammar and limited vocabulary, a linguistic design meant to limit the freedom of thought—personal identity, self-expression, free will—that ideologically threatens the régime of Big Brother and the Party, who thus criminalised such concepts as thoughtcrime. In "The Principles of Newspeak", the appendix to the 1949 novel, Orwell explains that Newspeak usage follows most of the English grammar, yet is a language characterised by a continually diminishing vocabulary; complete thoughts reduced to simple terms of simplistic meaning.>>

[Fred the Cat]

The composite image appears to show a torus. I may be donuts but it has made my hungry to search for toroidal shapes possible in nature. Universally, the geometric shapes created can be fascinating though some ideas are presented annoyingly!

Guess it’s just a coincident today's is in Taurus.

[sillyworm]

"Spinning 30 times a second.." Wow.....The jets ,in the X Ray data...are they products of the same process as the jets emitted by a black hole? What causes this spin?

[ThePiper]

Why does M1 not have a counter-jet?

[DL MARTIN]

Why does Stephen Hawking state, in his Briefer History of Time (page 82), that the Crab Nebula is 5000 light-years away?

[ta152h0]

almost looks like a cancer cell, in a gigantic size ( pictorially )

[MarkBour]

I love this merged image -- a splash of colors as beautiful as a rainbow. And I also loved bystander's presentation of the separate layers. What happens to a neutron star after another billion years?

[Chris Peterson]

Why does Stephen Hawking state, in his Briefer History of Time (page 82), that the Crab Nebula is 5000 light-years away?

We don't usually have very accurate distances for most objects. It's common to find ranges of 20% or more.

[BDanielMayfield]

What happens to a neutron star after another billion years?

It slows down somewhat, unless it is in a binary system where dramatic things can happen.

[Ann]

Why does M1 not have a counter-jet?

The visible jet of M87.
Photo: NASA and The Hubble Heritage Team

We can only see one jet in giant elliptical galaxy M87, too.

Wikipedia wrote about the jet in M87:
There is evidence of a counter jet, but this feature remains unseen from the Earth due to relativistic beaming.

Perhaps the Crab Nebula has a counter jet too, but for some reason we can't see it.

Ann

[Nitpicker]

This article attempts to explain and test the apparent differences in the jet and counter-jet:

http://cds.cern.ch/record/620859/files/0306162.pdf

I feel like I can just see a faint counter-jet in the x-ray (purple) image, but that may only be because I want to see it.

[Chris Peterson]

What happens to a neutron star after another billion years?

It slows down somewhat, unless it is in a binary system where dramatic things can happen.

If it was spinning very fast when it formed, it probably slows down a lot. And, of course, it also cools down.

[Chris Peterson]

"Spinning 30 times a second.." Wow.....The jets ,in the X Ray data...are they products of the same process as the jets emitted by a black hole? What causes this spin?

Most likely, all these astrophysical jets are produced by the same general process, involving material falling inward under the force of gravity towards a small body, acquiring a lot of energy in the process, and somehow interacting with rotating magnetic fields such that ionized matter and energetic particles are ejected along the axes of rotation.

The high spin of young neutron stars (and other compact bodies) is simply the result of conservation of angular momentum. You have something with the mass of several Suns, probably rotating at a "normal" stellar rate (a period measured in hours to weeks), which collapses down to a fraction of its original radius. So it has to increase its rotational rate, just like ice skaters do when they tuck their arms in during a spin.

[neufer]

What happens to a neutron star after another billion years?

It slows down somewhat, unless it is in a binary system where dramatic things can happen.

If it was spinning very fast when it formed, it probably slows down a lot. And, of course, it also cools down.

The crab nebula neutron star:

• Jet energy loss rate ~ 10⁴⁹ erg/millennium
  
  Rotational energy ~ 2 x 10⁴⁹ erg
  
  Gravitational energy ~ 30,000 x 10⁴⁹ erg

Certainly the jet energy loss must come directly from the rotational energy
and one might therefore expect to change significantly over a millennium.

The star could transfer some of it's gravitational energy into rotational energy by shrinking some & becoming less oblate
but that would only extend the time scale to something on the order of a million years NOT a billion years.