by neufer » Sun Dec 02, 2012 10:21 pm
Chris Peterson wrote:sinanipek wrote:
Is the Solar System a part of a nebula? I mean,
if we look to the Sun from, say, Sirius, can we see the nursing nebula from which Sol came from?
No. We're currently passing through a region were the interstellar medium is a bit denser, which you might think of as a sort of instrumentally detectable nebula, but as we usually use the word, we are not in a nebula. The nebula that our system formed from is long since dissipated.
http://en.wikipedia.org/wiki/Local_Interstellar_Cloud wrote:
<<The Local Interstellar Cloud (or Local Fluff or LIC) is the interstellar cloud roughly 30 light years or 9.2 parsecs across through which the Earth's Solar System is currently moving. It is currently unknown if the Sun is embedded in the LIC, or in the region where the LIC is interacting with the neighboring G-cloud.
The Solar System is thought to have entered the Local Interstellar Cloud at some time between 44,000 and 150,000 years ago and is expected to remain within it for another 10,000 to 20,000 years. The cloud has a temperature of about 6000 K, about the same temperature as the surface of the Sun. It is not very dense, with 0.3 atoms per cubic centimeter; less dense than the average for the interstellar medium in the Milky Way (0.5 atoms/cm³), though six times denser than the gas in the Local Bubble (0.05 atoms/cm³) which surrounds the local cloud. In comparison, Earth's atmosphere at the edge of space has 12 billion atoms per cubic centimeter, dropping to 52 million at 150 km.
The cloud is flowing outwards from the Scorpius-Centaurus Association, a stellar association that is a star-forming region. The cloud formed where the Local Bubble and the Loop I Bubble met.
The Sun is embedded in the Local Interstellar Cloud, as are a few other nearby stars including Alpha Centauri, Altair, Vega, Fomalhaut, and Arcturus. The Local Interstellar Cloud's potential effects on Earth are prevented by the solar wind and the Sun's magnetic field. This interaction with the heliosphere is under study by the
Interstellar Boundary Explorer (IBEX), a NASA satellite mapping the boundary between the Solar System and interstellar space.>>
[quote="Chris Peterson"][quote="sinanipek"]
Is the Solar System a part of a nebula? I mean,
if we look to the Sun from, say, Sirius, can we see the nursing nebula from which Sol came from?[/quote]
No. We're currently passing through a region were the interstellar medium is a bit denser, which you might think of as a sort of instrumentally detectable nebula, but as we usually use the word, we are not in a nebula. The nebula that our system formed from is long since dissipated.[/quote][quote=" http://en.wikipedia.org/wiki/Local_Interstellar_Cloud"]
[float=right][img2]http://upload.wikimedia.org/wikipedia/commons/thumb/7/74/Local_Interstellar_Clouds_with_motion_arrows.jpg/768px-Local_Interstellar_Clouds_with_motion_arrows.jpg[/img2][/float]
<<The Local Interstellar Cloud (or Local Fluff or LIC) is the interstellar cloud roughly 30 light years or 9.2 parsecs across through which the Earth's Solar System is currently moving. It is currently unknown if the Sun is embedded in the LIC, or in the region where the LIC is interacting with the neighboring G-cloud. [b][color=#0000FF]The Solar System is thought to have entered the Local Interstellar Cloud at some time between 44,000 and 150,000 years ago and is expected to remain within it for another 10,000 to 20,000 years. The cloud has a temperature of about 6000 K, about the same temperature as the surface of the Sun.[/color][/b] It is not very dense, with 0.3 atoms per cubic centimeter; less dense than the average for the interstellar medium in the Milky Way (0.5 atoms/cm³), though six times denser than the gas in the Local Bubble (0.05 atoms/cm³) which surrounds the local cloud. In comparison, Earth's atmosphere at the edge of space has 12 billion atoms per cubic centimeter, dropping to 52 million at 150 km.
The cloud is flowing outwards from the Scorpius-Centaurus Association, a stellar association that is a star-forming region. The cloud formed where the Local Bubble and the Loop I Bubble met. [b][color=#0000FF]The Sun is embedded in the Local Interstellar Cloud, as are a few other nearby stars including Alpha Centauri, Altair, Vega, Fomalhaut, and Arcturus.[/color][/b] The Local Interstellar Cloud's potential effects on Earth are prevented by the solar wind and the Sun's magnetic field. This interaction with the heliosphere is under study by the [url=http://asterisk.apod.com/viewtopic.php?f=31&t=18120&p=175318&hilit=ibex#p114942]Interstellar Boundary Explorer (IBEX)[/url], a NASA satellite mapping the boundary between the Solar System and interstellar space.>>[/quote]