Starship Asterisk*

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.

RedFishBlueFish wrote:
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.

http://www.academia.edu/738326/Notes_on_translations_of_the_East_Asian_records_relating_to_the_Supernova_of_AD_1054 wrote:
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.

RedFishBlueFish wrote: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.

Chris Peterson wrote:

RedFishBlueFish wrote:
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.

http://www.etymonline.com/ wrote:
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.

https://en.wikipedia.org/wiki/Newspeak wrote:
<<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.>>

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

MarkBour wrote:What happens to a neutron star after another billion years?

ThePiper wrote:Why does M1 not have a counter-jet?

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

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.

BDanielMayfield wrote:

MarkBour wrote: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.

sillyworm wrote:"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?

Chris Peterson wrote:

BDanielMayfield wrote:

MarkBour wrote:
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.

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