Starship Asterisk*

RocketRon wrote:Can even we see all these oorts that far out ?

RocketRon wrote:
Yes, they keep shifting the goalposts, without even consulting.
Alas, poor pluto the ex-planet.

Didn't they relatively recently announce that one of the Voyagers had left the Solar System.
That was nothing like that distance ?

Can even we see all these oorts that far out ?

• We can always see fallen oorts. But Voyager 1 will be defunct long before it reaches the cloud.

http://en.wikipedia.org/wiki/Voyager_1#Interstellar_medium wrote:

[b][color=#0000FF]Plot showing a dramatic decrease in the rate of solar wind particle detection by Voyager 1 (October 2011 through October 2012)[/color][/b]

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<<On September 12, 2013, NASA officially confirmed that Voyager 1 had reached the interstellar medium in August 2012 as previously observed, with a generally accepted date of August 25, 2012, the date durable changes in the density of energetic particles were first detected. By this point most space scientists had abandoned the belief that a change in magnetic field direction must accompany crossing of the heliopause; a new model of the heliopause predicted that no such change would be found. A key finding that persuaded many scientists that the heliopause had been crossed was an indirect measurement of an 80-fold increase in electron density, based on the frequency of plasma oscillations observed beginning on April 9, 2013, triggered by a solar outburst that had occurred in March 2012 (Electron density is expected to be two orders of magnitude higher outside the heliopause than within). Weaker sets of oscillations measured in October and November 2012 provided additional data. An indirect measurement was required because Voyager 1's plasma spectrometer had stopped working in 1980. In September 2013, NASA released audio renditions of these plasma waves. The recordings represent the first sounds to be captured in interstellar space.

While Voyager 1 is commonly spoken of as having left the Solar System simultaneously with having left the heliosphere, the two are not the same. The Solar System is usually defined as the vastly larger region of space populated by bodies that orbit the Sun. The craft is presently less than one seventh the distance to the aphelion of Sedna, and it has not yet entered the Oort cloud, the source region of long-period comets, regarded by astronomers as the outermost zone of the Solar System.

Voyager 1 will reach the Oort cloud in about 300 years and take about 30,000 years to pass through it. Though it is not heading towards any particular star, in about 40,000 years, it will pass within 1.6 light years of the star Gliese 445, which is at present in the constellation Camelopardalis. That star is generally moving towards the Solar System at about 119 km/s. NASA says that "The Voyagers are destined—perhaps eternally—to wander the Milky Way."

Provided Voyager 1 does not collide with anything and is not retrieved, the New Horizons space probe will never pass it, despite being launched from Earth at a faster speed than either Voyager spacecraft. New Horizons is traveling at about 15 km/s, 2 km/s slower than Voyager 1, and is still slowing down. When New Horizons reaches the same distance from the Sun as Voyager 1 is now, its speed will be about 13 km/s (vs. 17 km/s for Voyager 1).>>

RocketRon wrote:

neufer wrote:
Chris is extending the Solar System limits into the Oort Cloud.

The Oort cloud goes for half a light year (approx) out into space ?

http://en.wikipedia.org/wiki/Oort_cloud wrote:
<<The Oort cloud is thought to occupy a vast space from somewhere between
2,000 & 5,000 AU (0.03 & 0.08 ly) to as far as 50,000 AU (0.79 ly) from the Sun.>>

RocketRon wrote:
Mentioning the Solar System and a light year even in the same sentence seems a somewhat mismatched size comparison...

• Old fashion & parochial thinking!

neufer wrote: Chris is extending the Solar System limits into the Oort Cloud.

RocketRon wrote:

Chris Peterson wrote:

Dad is watching wrote:
Relative to our solar system, what would the dimensions of this nebula be? (diameter, height, width, etc?)

The object subtends about 25 arcseconds. At a distance of 8000 light years, that makes its size about one light year. Of course, it's asymmetrical, so that figure just gives a sense of dimension. But what it means is that the object is about the size of our solar system.

The size of our solar System is an interesting comment.

When Pluto is 'only' 5 or 6 light hours away, presumeably you are extending the Solar System limits far into space ??

Dad is watching wrote:Relative to our solar system, what would the dimensions of this nebula be? (diameter, height, width, etc?)

Chris Peterson wrote:The object subtends about 25 arcseconds. At a distance of 8000 light years, that makes its size about one light year. Of course, it's asymmetrical, so that figure just gives a sense of dimension. But what it means is that the object is about the size of our solar system.

Boomer12k wrote:If everything is known to be true by conjecture.... Why look?

neufer wrote:

• Hubble mostly relied & utilized the hard work of others:

http://en.wikipedia.org/wiki/Vesto_Slipher wrote:
<<Edwin Hubble is commonly incorrectly credited with discovering the redshift of galaxies; these measurements and their significance were understood before 1917 by James Edward Keeler (Lick & Allegheny), Vesto Melvin Slipher (Lowell), and William Wallace Campbell (Lick) at other observatories. Combining his own measurements of galaxy distances with Vesto Slipher's measurements of the redshifts associated with the galaxies, Hubble and Milton Humason discovered a rough proportionality of the objects' distances with their redshifts. This redshift-distance correlation, nowadays termed Hubble's law, was formulated by Hubble and Humason in 1929 and became the basis for the modern model of the expanding universe.>>

Chris Peterson wrote:

Boomer12k wrote:
Hubble.... A true scientist....

Did not rely on theory, and conjecture, smashed the limited theories....changed Einstein's view, and changed Astronomy forever... And the instrument named after him has done a splendid job of continuing that legacy....

Say what? Hubble totally relied on theory. He totally utilized conjecture. That's exactly what scientists do!

• Hubble mostly relied & utilized the hard work of others:

http://en.wikipedia.org/wiki/Vesto_Slipher wrote:
<<Edwin Hubble is commonly incorrectly credited with discovering the redshift of galaxies; these measurements and their significance were understood before 1917 by James Edward Keeler (Lick & Allegheny), Vesto Melvin Slipher (Lowell), and William Wallace Campbell (Lick) at other observatories. Combining his own measurements of galaxy distances with Vesto Slipher's measurements of the redshifts associated with the galaxies, Hubble and Milton Humason discovered a rough proportionality of the objects' distances with their redshifts. This redshift-distance correlation, nowadays termed Hubble's law, was formulated by Hubble and Humason in 1929 and became the basis for the modern model of the expanding universe.>>

• . https://telescoper.wordpress.com/2012/0 ... s-slipher/

Ann wrote:
Judging from that diagram, it looks like the planetary nebula phase starts when the parent star has a temperature of about 3,500 K. The stellar corpse then gets hotter until it hits a temperature of about 7,000 - 10,000 K. Obviously that is not correct. In order to ionize an emission nebula, a star has to have a temperature of at least 20,000 K.

• The rest of the Story

Boomer12k wrote:Hubble.... A true scientist....

Did not rely on theory, and conjecture, smashed the limited theories....changed Einstein's view, and changed Astronomy forever... And the instrument named after him has done a slendid job of continueing that legacy....

neufer wrote:

https://saoastronews.wordpress.com/2012/11/09/binary-drives-pne/ wrote:

[b][color=#0000FF]Hertzsprung-Russell(HR) diagram, showing the evolutionary phase of a low mass star towards the planetary nebulae phase. (Credit: Swinburne)[/color][/b]

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• SAO astro news

<<Planetary nebulae (PNe) come in a wide variety of shapes, with complex morphologies including asymmetries, bipolar jets and high-velocity outflows. The origin of their complex structure has been debated for many years – how can a spherical star produce such an asymmetric structure? The resulting asymmetry is likely due to processes that occurred during the main mass-loss phase of the star and are thought to result from a central binary system, or structure in the local stellar magnetic field, or both.>>

alex_space wrote:
I suppose the dying star is the white dot inside the green region.
Why is it not centered in the dark part of the green region ?
For what reason symmetry is broken ?

• It might be part of a binary star system but is >10,000 more luminous than it's companion:

https://saoastronews.wordpress.com/2012/11/09/binary-drives-pne/ wrote:

[b][color=#0000FF]Hertzsprung-Russell(HR) diagram, showing the evolutionary phase of a low mass star towards the planetary nebulae phase. (Credit: Swinburne)[/color][/b]

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• SAO astro news

<<Planetary nebulae (PNe) come in a wide variety of shapes, with complex morphologies including asymmetries, bipolar jets and high-velocity outflows. The origin of their complex structure has been debated for many years – how can a spherical star produce such an asymmetric structure? The resulting asymmetry is likely due to processes that occurred during the main mass-loss phase of the star and are thought to result from a central binary system, or structure in the local stellar magnetic field, or both.>>

Dad is watching wrote:

APOD Robot wrote: this brief, spectacular, closing phase of a Sun-like star

Relative to our solar system, what would the dimensions of this nebula be? (diameter, height, width, etc?) Also, what controls the general shape of the ejected material? Does it align with the axis of rotation of the star, the magnetic field of the star, or the plane of an (assumed) accretion disk/planetary system, or is some other natural force in control?

Dad is watching wrote:Relative to our solar system, what would the dimensions of this nebula be? (diameter, height, width, etc?)

Also, what controls the general shape of the ejected material? Does it align with the axis of rotation of the star, the magnetic field of the star, or the plane of an (assumed) accretion disk/planetary system, or is some other natural force in control?

Ann wrote:The Eye in the Sky. I'm just saying.

What is it about this planetary nebula that makes it look like a green eye surrounded by two sets of red rings?

Ann

APOD Robot wrote: this brief, spectacular, closing phase of a Sun-like star