Astrophysics and Cosmology - Discuss the Universe here

[onan]

Look at my posts in the OSOM thread the night I hurt OstrichThief's feelings when he made claims about Hoagland being the origins of the ice on Europa. Or search expat and Philip Plait's blogs. I think astroguy might even have a multipart podcast. 

It starts around here:

Thanks for the link. I don't usually follow hoagland or his thread.

[GravitySucks]

Thanks for the link. I don't usually follow hoagland or his thread.

Bottom line is, yes, we certainly knew that Europa had water ice some time in the 70's, maybe earlier through spectrum analysis. NASA made the decision to do a flyby with Voyager in 79 and that confirmed it and gave us the first decent pictures of the "cracks" and the extent of the surface ice.

We still don't know how much there is, but is a lot. I read one article a few weeks back that claimed Europa had more water than our own oceans. I have troubles accepting that since Europa is slightly smaller than our moon.

[zeebo]

Just bumping my question. Seriously, does anyone know what known about Europa at the time of 2010's publication in 1982? Did they suspect water back then?

Underrated movie imho.  I thought the Jupiter aero-braking scene was pretty cool for its time.

[GravitySucks]

I believe there is a problem with the ESA Mars lander. The orbiter seems to be in good shape but I don't think they have had contact with the lander since it entered Mars atmosphere.

https://twitter.com/esaoperations/status/788812352988844033

Breaking: my suspicions confirmed: https://www.theguardian.com/science/across-the-universe/live/2016/oct/19/mars-landing-esa-attempts-to-set-schiaparelli-probe-on-red-planet-live

[GravitySucks]

Looks like the ESA Mars probe did in fact crater in

http://www.bbc.com/news/science-environment-37731671

[GravitySucks]

http://www.npr.org/sections/thetwo-way/2016/10/30/499751470/nasas-new-intruder-alert-system-spots-an-incoming-asteroid

[KevinIsAHybrid]

I read from a book that Universe is like a cell!

[GravitySucks]

Turned the corner and heading to another solar mininum.

http://www.vencoreweather.com/blog/2016/10/31/1040-am-sun-quiet-again-as-it-heads-towards-solar-minimum

[GravitySucks]

https://youtu.be/zVScPy-fiGM

[zeebo]

Planet Orbiting Nearest Star Could be Habitable

A rocky extrasolar planet with a mass similar to Earth’s was recently detected around Proxima Centauri, the nearest star to our sun. This planet, called Proxima b, is in an orbit that would allow it to have liquid water on its surface, thus raising the question of its habitability. In a study to be published in The Astrophysical Journal Letters, an international team led by researchers at the Marseille Astrophysics Laboratory (CNRS/Aix-Marseille Université) has determined the planet’s dimensions and properties of its surface, which actually favor its habitability.

http://www.nasa.gov/feature/jpl/study-planet-orbiting-nearest-star-could-be-habitable

[Camazotz Automat]

Planet Orbiting Nearest Star Could be Habitable

A rocky extrasolar planet with a mass similar to Earth’s was recently detected around Proxima Centauri, the nearest star to our sun. This planet, called Proxima b, is in an orbit that would allow it to have liquid water on its surface, thus raising the question of its habitability. In a study to be published in The Astrophysical Journal Letters, an international team led by researchers at the Marseille Astrophysics Laboratory (CNRS/Aix-Marseille Université) has determined the planet’s dimensions and properties of its surface, which actually favor its habitability.

http://www.nasa.gov/feature/jpl/study-planet-orbiting-nearest-star-could-be-habitable

Since it is in the correct star system, if we do send a light sail probe to Alpha Centauri, we absolutely need to name some component of the project "Jupiter II."

Breakthrough Starshot possible flyby of Proxima Centauri b

[zeebo]

^^ Project Starshot rules.  Anyone not familiar may want to check out Amy's discussion w/ Dr. Philip Lubin here (this is only the first hour, but gives an idea what it's about.)


https://www.youtube.com/watch?v=D8U0GSxfH7s

[Camazotz Automat]

Just got back from a quick Super Moon night drive.  It's still at 99% full. 

I pulled over at a truck stop just outside of G-------- and took this incredible photo:

[trostol]

question..maybe stupid

Say we were on a planet in the Andromeda galaxy or..any other..would the constellations we see in our night sky, say, Orion, look the same from there?

[=Schlyder=]

question..maybe stupid

Say we were on a planet in the Andromeda galaxy or..any other..would the constellations we see in our night sky, say, Orion, look the same from there?

No, you wouldn't see any of the constellations we see.   The constellations we can see are stars within our own Milky Way galaxy.

[zeebo]

No, you wouldn't see any of the constellations we see.   The constellations we can see are stars within our own Milky Way galaxy.

Yep but even within our own galaxy, you wouldn't have to go that far - on the astronomical scale - to see the constellations start to shift and then eventually disappear altogether.  Take Orion's Belt for instance.  Although the three stars seem like the same distance from us, the middle one is actually roughly twice as far away as the other two, but since it has a much higher absolute luminosity it appears from our vantage point to be at the same depth.  What we're really seeing is sort of an edge-on triangle, which would look different depending on where you were.

Of course sometimes certain stars really are close together e.g. binary stars and they'd look pretty similar from any direction.  One example of this is the second star from the end of the Big Dipper's handle, which is actully two stars Mizar & Alcor.  You can easily resolve these as distinct objects with good binocs or a telescope.  There are stories btw that in ancient times the ability to see them both with the naked eye was an eyesight test.

[trostol]

well now i have to scrap my story lol

[=Schlyder=]

Yep but even within our own galaxy, you wouldn't have to go that far - on the astronomical scale - to see the constellations start to shift and then eventually disappear altogether.  Take Orion's Belt for instance.  Although the three stars seem like the same distance from us, the middle one is actually roughly twice as far away as the other two, but since it has a much higher absolute luminosity it appears from our vantage point to be at the same depth.  What we're really seeing is sort of an edge-on triangle, which would look different depending on where you were.

Of course sometimes certain stars really are close together e.g. binary stars and they'd look pretty similar from any direction.  One example of this is the second star from the end of the Big Dipper's handle, which is actully two stars Mizar & Alcor.  You can easily resolve these as distinct objects with good binocs or a telescope.  There are stories btw that in ancient times the ability to see them both with the naked eye was an eyesight test.

exactly... I  just didn't feel like going into the whole parallax explanation.  We can see the changes of the constellations from modeling of earth's precession from the past to current times.

[trostol]

my question was wrong any way lol

[Rix Gins]

my question was wrong any way lol

Still, it was a cool question.  It made me think (wrongly) that if I had a spaceship that could traverse time and space, I could pass through the Big Dipper, turn around and still see the Big Dipper, only it would be backwards. lol  I'm glad zeebo and Schlyder understand the stars, because I sure don't.  Haha

[trostol]

Still, it was a cool question.  It made me think (wrongly) that if I had a spaceship that could traverse time and space, I could pass through the Big Dipper, turn around and still see the Big Dipper, only it would be backwards. lol  I'm glad zeebo and Schlyder understand the stars, because I sure don't.  Haha

i misthought at the hour i posted it lol the planet isn't in another galaxy..just another solar system lol

from what i had read it would still look like Orion on say..Mars..just a different.."angle"

[zeebo]

exactly... I  just didn't feel like going into the whole parallax explanation.  We can see the changes of the constellations from modeling of earth's precession from the past to current times.

The precession of the earth is pretty interesting too.  Every 26,000 yrs. (I had to check wiki for that) ... the axis going out the north pole traces out a circle in the sky.  Ten thousand years ago or so I think it was Vega which served as a decent 'north star', but count yourselves lucky folks, we're actually living in the golden age of Polaris being in the perfect sweet spot for it.

[ItsOver]

Just got back from a quick Super Moon night drive.  It's still at 99% full. 

I pulled over at a truck stop just outside of G-------- and took this incredible photo:

"Cam...phone home."

[zeebo]

i misthought at the hour i posted it lol the planet isn't in another galaxy..just another solar system lol

from what i had read it would still look like Orion on say..Mars..just a different.."angle"

I'm fairly sure our constellations would look the same within our own solar system, even as far out as say Pluto.  I'm thinking it would be like standing on a beach, looking out a skyline on some distant shore, then walking ten feet down the beach - the relative distance change is so small, the skyline would look the same.  However once you go out as far as the nearest stars you'd start seeing some changes I think.  So I think you can still do your story if you stay 'local'.   

[trostol]

here's one...I am playing Mass effect for like the 50th time and it got me wondering..say a planet it found some where and colonized but has a longer ..orbital period 2..3..10 years to go around its son and say you are born onto that planet..does your life span change or does that take a few..generations if not longer or would there in fact be no bearing at all?

[zeebo]

here's one...I am playing Mass effect for like the 50th time and it got me wondering..say a planet it found some where and colonized but has a longer ..orbital period 2..3..10 years to go around its son and say you are born onto that planet..does your life span change or does that take a few..generations if not longer or would there in fact be no bearing at all?

You'd still live the same number of 'earth years', but you'd experience longer seasons.  Think Game of Thrones:  "Winter is coming".     Now over time, who knows how life would evolve with such environmental differences.  I did see somewhere that on Mars eventually future generations would be taller and thinner because of lower gravity. 

[GravitySucks]

Interesting find in reviewing archived Hubble images over a 16 year period.

https://astronomynow.com/2017/01/10/hubble-captures-shadow-play-caused-by-possible-planet/

[Evil Twin Of Zen]

http://www.youtube.com/watch?v=nzkns8GfV-I

[zeebo]

I don't know the image process behind this, but it's the nearest I've seen to actually feeling like you're just hanging out on Mars.

https://kuula.co/post/7l4jJ

[twiki]

http://www.youtube.com/watch?v=nzkns8GfV-I

this is just beautiful. thanks for posting.