Starship Asterisk*

flamespaceship wrote:The large scale interactions amongst dust, gases and stars are often amazingly beautiful and awe-inspiring. Is enough known about the distribution of stars, dust and gases in the vicinity our our Sun and its neighboring stars to be able to reconstruct how our region of space might appear to a distant observer? They must be out there looking, so what do they see?

flamespaceship wrote:The large scale interactions amongst dust, gases and stars are often amazingly beautiful and awe-inspiring. Is enough known about the distribution of stars, dust and gases in the vicinity our our Sun and its neighboring stars to be able to reconstruct how our region of space might appear to a distant observer? They must be out there looking, so what do they see?

Mario wrote:gee!... What a panorama!
I wonder how would be to see at this stellar field, on an hypotetical planet, orbiting around a star, just in the middle of this breathtaking view...
Maybe too many GIGANTIC stars in so small volume, would let the nighttime lit as daytime... who knows!

gar37bic wrote:

Mario wrote:
I wonder how would be to see at this stellar field, on an hypothetical planet, orbiting around a star, just in the middle of this breathtaking view... Maybe too many GIGANTIC stars in so small volume, would let the nighttime lit as daytime... who knows!

I was just thinking similar thoughts - if one lived on a planet in the midst of such a cluster,
it might be daytime-bright, or at least moonlight-bright, all the time.

• Moonlight bright at most.

gar37bic wrote:
But that raises two questions - one, would the additional influx of UV and extrasolar particle streams (cosmic rays, etc.) make it impossible for life as we know it? And also, I wonder if having many stars close by would cause gravitational drag, slowing planets down until they fall into uninhabitable range or into their star itself?

eltodesukane wrote:
Over the last 4 billions years, as the Sun rotates around the galaxy, crossing galactic arms and passing through who knows what clouds or clusters, I wonder what are the probability of the Earth never coming too close to a lethal exploding supernova. Only the lucky ones would live to tell.

http://en.wikipedia.org/wiki/Near-Earth_supernova wrote:
<<Adrian L. Melott et al. estimated that gamma ray bursts from "dangerously close" supernova explosions occur two or more times per billion years, and this has been proposed as the cause of the end Ordovician extinction, which resulted in the death of nearly 60% of the oceanic life on Earth. Type Ia supernovae are thought to be potentially the most dangerous if they occur close enough to the Earth. Because Type Ia supernovae arise from dim, common white dwarf stars, it is likely that a supernova that could affect the Earth will occur unpredictably and take place in a star system that is not well studied. One theory suggests that a Type Ia supernova would have to be closer than 10 parsecs to affect the Earth. On average, a supernova explosion occurs within 10 parsecs of the Earth every 240 million years. Gamma rays are responsible for most of the adverse effects a supernova can have on a living terrestrial planet. In Earth's case, gamma rays induce a chemical reaction in the upper atmosphere, converting molecular nitrogen into nitrogen oxides, depleting the ozone layer enough to expose the surface to harmful solar and cosmic radiation. Phytoplankton and reef communities would be particularly affected, which could badly deplete the base of the marine food chain.

Evidence from daughter products of short-lived radioactive isotopes shows that a nearby supernova helped determine the composition of the Solar System 4.5 billion years ago, and may even have triggered the formation of this system. Supernova production of heavy elements over astronomic periods of time ultimately made the chemistry of life on Earth possible.

In 1996, astronomers at the University of Illinois at Urbana-Champaign theorized that traces of past supernovae might be detectable on Earth in the form of metal isotope signatures in rock strata. Subsequently, iron-60 enrichment has been reported in deep-sea rock of the Pacific Ocean by researchers from the Technical University of Munich. 23 atoms of this iron isotope were found in the top 2 cm of crust, and these date from the last 13 million years or so. It is estimated that the supernova must have occurred in the last 5 million years or else it would have had to have happened very close to the solar system to account for so much iron-60 still being here. A supernova occurring as close as would have been needed would have probably caused a mass extinction, which didn't happen in that time frame.

In 2009, researchers have found nitrates in ice cores from Antarctica at depths corresponding to the known supernovae of 1006 and 1054 CE, as well as from around 1060 CE. The nitrates were apparently formed from nitrogen oxides created by gamma rays from the supernovae. This technique should be able to detect supernovae going back several thousand years.>>

neufer wrote:The Westerlund 1 super star cluster has never gotten an APOD

http://en.wikipedia.org/wiki/Westerlund_1 wrote:
Wd1 is too remote for direct measurement of the distance via parallax measurements, and the distance must be estimated from the expected absolute magnitude of the stars and estimates of the extinction towards the cluster. This has been done for both the yellow hypergiant[2] and Wolf–Rayet[6] populations, yielding estimates around 5 kpc in both cases, while a determination from the main-sequence population suggests 3.6 kpc.[7] These estimates all place Wd1 near the outer edge of the Galactic bar, which may be significant in determining how such a massive cluster formed.

neufer wrote:The Westerlund 1 super star cluster has never gotten an APOD

Chris Peterson wrote:

flamespaceship wrote:The large scale interactions amongst dust, gases and stars are often amazingly beautiful and awe-inspiring. Is enough known about the distribution of stars, dust and gases in the vicinity our our Sun and its neighboring stars to be able to reconstruct how our region of space might appear to a distant observer? They must be out there looking, so what do they see?

Sure. Our region of the galaxy is largely unobscured by dust, so we know it very well. A skilled renderer could produce an accurate simulated view of our region from another viewpoint. It wouldn't be very interesting in comparison with images like today's APOD. We're in a little bubble of gas which would glow slightly instrumentally, but there isn't much going on here. Which is a good thing for us!

flamespaceship wrote:Are you implying that even the few old stars with planets (and potentially with life) that happen to be in the vicinity of these photogenic nebulae would be sterilized by the intense radiation emitted by all of those many young energetic stars whose emissions light these nebulae?

If that logic holds, do the current planet searches focus on quiescent older regions of the galaxy to increase the odds of finding planets in less toxic environments?