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[demosthenes]

It is widely accepted that there is a super massive black hole at the center of our galaxy (and at the center of most/all galaxies). We can't however see this back hole due to thick dust clouds along the galactic plane.

As for why it is bright, that has been confusing me for a while too. I thought black holes are, well, black, i.e. invisible. But I recently watched in interview with Micho Kaku (spelling?) who said if weren't for the dust clouds obscuring our view, then the black hole at the center of our galaxy would appear brighter than the full moon at night to the naked eye! That caught me off guard and I still don't know the explanation (didn't try to look it up)...

Perhaps it has to do with the massive amounts of matter (including nearby stars) that are being constantly sucked in by the black hole? All that tearing and compressing of matter and space time around the event horizon must be releasing insane amounts of energy (and thus glows?)... Also don't objects going into the black hole apprear (for a distant observer) to be continually slowing down as they approach the event horizon but never fully reach it (relativity)? Which might explain the intense brightness, as all that mass would appears to be accumilating in ever growing quantities around the black hole since an observer can never see something "go inside".

I wrote all that from bed on my phone as I struggle to sleep at 6 in the morning. Phone web browser doesn't support tabs so I can't look up any of that to verify it. So might all be wrong

I was told by my astronomy Professor that stars are just closer together near the center of the galaxy, so close in fact that in some areas you wouldn't experience a night time like we do here on Earth on some planets.

 

[Naked Snake]

I was told by my astronomy Professor that stars are just closer together near the center of the galaxy, so close in fact that in some areas you wouldn't experience a night time like we do here on Earth on some planets.

I wonder how life which evolved on a planet that does not have a day/night cycle like Earth would be. I believe all creatures on Earth sleep because we have a 24hr cycle. Some planets revolve around stars always facing the same way (like our moon does around Earth), so one side would always be in light and the other always in dark, and as you said some planets probably have no dark side at all due to being close to many stars.

If life evolves on such planets the creatures might not know what sleep is, pretty interesting.

Edit: Not sure if the word "creatures" is approperiate when you don't believe in creationism

 

[Hawk SE]

The phrase you were looking for is "tidal locked".

Yeah would be interesting, just sad all of us will never know these answers.

 

[The Elite]

saddest looking planet ever

Chicks dig scars.

 

[Melchiah]

Chicks dig scars.

True.

 

[CabbageRed]

If life evolves on such planets the creatures might not know what sleep is, pretty interesting.

For fun.

A galactic core (or any crowded bit of space) should be exceptionally hostile to any attempts to get life, especially complicated life, going. That said, if such lifeforms did exist, I think it would be more likely that the ever-present light would not stop them from sleeping. Nocturnal animals on our own planet illustrate that darkness is not required for sleep. Plus, the heat and increased amount of radiation (relative to Earth) would likely result in tough, thick skin which could double as excellent eyelids (assuming their senses and anatomy had need of them). Of course, while I believe every animal on Earth needs sleep of some sort, creatures elsewhere may evolve along a different path (I forget what it's called, but certain predispositions get "locked" in during the course of evolution) so maybe the universe is teaming with populated but sleepless planets.

 

[Extollere]

I wonder how life which evolved on a planet that does not have a day/night cycle like Earth would be. I believe all creatures on Earth sleep because we have a 24hr cycle. Some planets revolve around stars always facing the same way (like our moon does around Earth), so one side would always be in light and the other always in dark, and as you said some planets probably have no dark side at all due to being close to many stars.

If life evolves on such planets the creatures might not know what sleep is, pretty interesting.

Edit: Not sure if the word "creatures" is approperiate when you don't believe in creationism

I read somewhere once before that it isn't speculated that there are many planets (or any) closer to the center of the galaxy. Reason being that most of the suns there are super giants, and too close together to have kind of stable and/or safe gravitational fields. No orbits that can house planets without destroying them, and no habitable zones. IIRC most of the planets are located in the various spiral arms. The center is just where old stars go to die.

 

[Mr. Luchador]

That's always bugged me about the definition of life - its our definition, based on what we know and understand. OK, so it makes sense to start there, but it always comes across as that's it, that's the only way.

Like the same way the communicate via the periodic table and math since they consider it 'Universal'!

 

[Extollere]

Like the same way the communicate via the periodic table and math since they consider it 'Universal'!

The reason why people often say this is because the laws of physics are the same anywhere you go in the Universe. If the laws of physics are the same on another solar system that harbors life, and if those beings have a method of science to understand them, then we have some kind of universal commonality, communication/understanding-wise. This of course, says nothing of whether or not we could communicate with them, even if we made contact.

 

[Mr. Luchador]

Haven't the laws of physics been questioned, tested, challenged, and changed since the dawn of man? Hardly a constant.

 

[ezrarh]

Haven't the laws of physics been questioned, tested, challenged, and changed since the dawn of man? Hardly a constant.

Our mathematical description of the laws of physics have evolved over time to more accurately describe the laws of nature. However I assure you, gravity has always been gravity.

 

[Extollere]

Haven't the laws of physics been questioned, tested, challenged, and changed since the dawn of man? Hardly a constant.

Yes of course. But because our understanding of them changed with better applications of science. Not because the physical properties of the Universe changed. What I'm saying is that those properties, those laws of the Universe (not the laws we decree upon the Universe), are the same everywhere regardless of our understanding or interpretation of them. Some of the laws that we postulate are accurate to such an extraordinary degree that they work for us with predictable results. It's because of this commonality that you hear things like "math is a universal language" etc, because certain equations and properties (like the speed of light for example) will act the same everywhere in the Universe.

 

[Mr. Luchador]

Our mathematical description of the laws of physics have evolved over time to more accurately describe the laws of nature. However I assure you, gravity has always been gravity.

In the literal sense, it probably is, but yeah, our understanding and point of view of what we consider 'universal' changes all the time. That's what I was getting at, we're looking and searching based on us, which I guess is a logical starting point.

 

[Stinkles]

It is widely accepted that there is a super massive black hole at the center of our galaxy (and at the center of most/all galaxies). We can't however see this back hole due to thick dust clouds along the galactic plane.

As for why it is bright, that has been confusing me for a while too. I thought black holes are, well, black, i.e. invisible. But I recently watched in interview with Micho Kaku (spelling?) who said if weren't for the dust clouds obscuring our view, then the black hole at the center of our galaxy would appear brighter than the full moon at night to the naked eye! That caught me off guard and I still don't know the explanation (didn't try to look it up)...

Perhaps it has to do with the massive amounts of matter (including nearby stars) that are being constantly sucked in by the black hole? All that tearing and compressing of matter and space time around the event horizon must be releasing insane amounts of energy (and thus glows?)... Also don't objects going into the black hole apprear (for a distant observer) to be continually slowing down as they approach the event horizon but never fully reach it (relativity)? Which might explain the intense brightness, as all that mass would appears to be accumilating in ever growing quantities around the black hole since an observer can never see something "go inside".

I wrote all that from bed on my phone as I struggle to sleep at 6 in the morning. Phone web browser doesn't support tabs so I can't look up any of that to verify it. So might all be wrong

Brightness ios from energetic radioactive emissions from gas (and dust) being sucked into the black hole, but from far outside the point of no return. So light can still easily escape. Think about the foam at the edge of a whirlpool - a very visible phenomenon from the calmest point of the vortex.

 

[CabbageRed]

In the literal sense, it probably is, but yeah, our understanding and point of view of what we consider 'universal' changes all the time. That's what I was getting at, we're looking and searching based on us, which I guess is a logical starting point.

Right. I think all good science has an asterisk next to it (theory of whatever), but for the ease of conversation this is usually left out. That said, we can see very far back in time and the rules governing mass/energy appear to be consistent. You could point to black holes, but that would really just highlight a large hole in our own understanding of the universe. All aberrations of the laws of physics would only expose our own ignorance rather than an actual change in the "laws."

 

[PantherLotus]

You guys see Through the Wormhole last night? Great episode that comes down to this:

If time is real, it can be tested by measuring the speed of particles coming from a GRB in an older part of the universe (based on the idea that time and space are related through gravity, and that weaker particles will be less affected by gravity the further they travel). A couple billion light years away, we should be able to see up to a 1-second (ONE SECOND!) difference between particles if time actually exists.

Basically, the test would refute the idea that everything is happening at once -- because those particles would arrive at the same time.

I know I've butchered the explanation, and am open to a better or more concise version if one of you can. Either way, it's freaking fascinating.

 

[a176]

'weaker particles' ?

 

[Hootie]

http://www.npr.org/2011/06/25/137414737/among-the-costs-of-war-20b-in-air-conditioning

Not a space-related article, but I think the first sentence speaks for itself.

We spend more money on keeping soldiers cool every year than we spend on NASA's annual budget. This makes me really, really sad.

 

[Naked Snake]

http://www.npr.org/2011/06/25/137414737/among-the-costs-of-war-20b-in-air-conditioning

Not a space-related article, but I think the first sentence speaks for itself.

We spend more money on keeping soldiers cool every year than we spend on NASA's annual budget. This makes me really, really sad.

Damn

 

[fierrotlepou]

http://www.npr.org/2011/06/25/137414737/among-the-costs-of-war-20b-in-air-conditioning

Not a space-related article, but I think the first sentence speaks for itself.

We spend more money on keeping soldiers cool every year than we spend on NASA's annual budget. This makes me really, really sad.

They're all selfish pricks. This is very sad, because everyone is just looking past the important things in life.

 

[params7]

Hubble photograph of Centaurus A reveals bright jewel behind dust

Wow..fantastic. Thing song played while I was browsing that picture and that even made it a fantastic experience as I read about.

 

[Hawk SE]

Variations in the Night Sky.

 

[PantherLotus]

I don't believe zone 1 is real.

 

[wolfmat]

I don't believe zone 1 is real.

Desert / ocean.

 

[Gvaz]

Where I live in maine I'd say my house is between 1 and 3 easily.

In Boston it's easily a 9.

 

[RSTEIN]

I've seen #1 at about 3:00 am over Lake Erie. Amazing.

 

[Hawk SE]

Where I live is a 5, where wife's parents live is a 3.

 

[LQX]

Living in NY, 5-9 is all I ever seen. I would probably fall into shock if I ever saw 1-3 today. Haven't seen skies like that since I was kid.

 

[Angry Fork]

Living in NY, 5-9 is all I ever seen. I would probably fall into shock if I ever saw 1-3 today. Haven't seen skies like that since I was kid.

Same here. I wish so bad I could see a desert sky one day.

http://www.npr.org/2011/06/25/137414737/among-the-costs-of-war-20b-in-air-conditioning

Not a space-related article, but I think the first sentence speaks for itself.

We spend more money on keeping soldiers cool every year than we spend on NASA's annual budget. This makes me really, really sad.

Monumentally depressing.

 

[PantherLotus]

I would *love* to see a map of those light pollution zones.

 

[XMonkey]

I would *love* to see a map of those light pollution zones.

I'm pretty sure this was posted awhile back in this thread, but there is such a thing: the Dark Sky Finder.

 

[Maklershed]

I live in zone 5 (although sometimes it can look like 3) and ironically I've been noticing Altair recently and wondering what I was seeing. At first I thought it was double vision glare from my window but then I realized it was two stars close together.

 

[Scrow]

I'm pretty sure this was posted awhile back in this thread, but there is such a thing: the Dark Sky Finder.

i want one for australia

 

[GroteSmurf]

i want one for australia

You can make one The source code is available.

 

[derFeef]

Where I live in maine I'd say my house is between 1 and 3 easily.

Wow, at what sea-level do you live? 1 is really uncommon for non-desert, mountain or ocean places.
I was in the alps with my telescope once and I was shocked, looking through the okular was almost blinding. Too many stars - it was hard to navigate the sky at first because I could not find my reference points.

 

[Tha Robbertster]

The most beatifull thing I ever saw was the night sky in New-Sealand. We were somewhere on the southern Island and you could see an entire ''arm'' of the milky way.

I thought I saw 2 clouds in the sky but they were other galaxys... An incredible experience, makes you feel so small.

 

[hirokazu]

I don't believe zone 1 is real.

I've seen it with my own eyes in rural Australia. Or at least I think it's Zone 1, because Zone 3 doesn't seem to have that many stars compared to what I saw. :0

 

[Antagon]

Planning to visit Salar de Uyuni this year (largest salt flats in the world) so hopefully I'll get to see a zone 1 sky. As a Dutchie the best I normally see is a zone 5 I guess.

 

[fallout]

I thought I saw 2 clouds in the sky but they were other galaxys... An incredible experience, makes you feel so small.

That would have been the Magellanic Clouds, so I wouldn't feel too bad about mistaking them for something more earthly.

There's also a neat effect that can be seen in dark skies when no Moon is present called the Zodiacal Light (certain times of the year are preferable, as well). At night, the sun is still shining of course. Sunlight scatters off of the interplanetary dust that is found along the orbital plane of our solar system (i.e., the ecliptic) and creates a faint glow in the night sky along that line.

 

[Kaako]

Southern Ocean Sky by Alexy Cherney. Magnificent footage.

 

[Noirulus]

That looks amazing. I'm having trouble believing the video hasn't been tampered with during editing.

 

[Raistlin]

Desert / ocean.

A lot of it is elevation.

Basically look at locations where large-scale optical telescopes are stationed. The locations are selected for a reason.

 

[AceBandage]

Southern Ocean Sky by Alexy Cherney. Magnificent footage.

Gorgeous.

 

[Scrow]

http://www.npr.org/2011/06/25/137414737/among-the-costs-of-war-20b-in-air-conditioning

Not a space-related article, but I think the first sentence speaks for itself.

We spend more money on keeping soldiers cool every year than we spend on NASA's annual budget. This makes me really, really sad.

 

[Hootie]

US Lawmakers kill off funding for the successor to the Hubble Space Telescope

 

[Hawk SE]

I'm glad Atlantis successfully launched into space.

 

[popeutlal]

Beautiful dust storm on Saturn.

www.sciencedaily.com/releases/2011/...encedaily+(ScienceDaily:+Latest+Science+News)

 

[Lime]

In relation to the above:

Saturn Storm Panoramas
Credit: Cassini Imaging Team, SSI, JPL, ESA, NASA

Explanation: These tantalizing panoramas follow a remarkable giant storm encircling the northern hemisphere of ringed planet Saturn. Still active, the roiling storm clouds were captured in near-infrared images recorded by the Cassini spacecraft on February 26 and stitched into the high resolution, false-color mosaics. Seen late last year as a prominent bright spot by amateur astronomers when Saturn rose in predawn skies, the powerful storm has grown to enormous proportions. Its north-south extent is nearly 15,000 kilometers and it now stretches completely around the gas giant's northern hemisphere some 300,000 kilometers. Taken about one Saturn day (11 hours) apart, the panoramas show the head of the storm at the left and cover about 150 degrees in longitude. Also a source of radio noise from lightning, the intense storm may be related to seasonal changes as Saturn experiences northern hemisphere spring.

Today's APOD

 

[UltimaPooh]

The Sagan Series End of an Era

 

[Kaako]

The Sagan Series End of an Era

Love the Sagan series. Thanks for posting the new one.
Also, those storm pics are pretty amazing. The close-up one looks like a freaking painting.