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Old 2006-01-12, 02:31   Link #1
Muir Woods
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The Astronomy Discussion Thread

I remember there was an astronomy thread, so I searched the forums for astro/astronomy but did not find it. Perhaps it was lost due to the hack incident. Hence, here's a new thread to have casual or critical discussions related to astronomy. Anyways, the news I want to bring is:

The most detailed observation of the Messier object 42 (M42, or more commonly known as The Orion Nebula) has just been completed by The Hubble Space Telescope. Over 100 Hubble orbits, Hubble snapshotted mosaics of M42 amounting to a billion pixels, creating one of the most detailed and largest astronomical image ever released to the public. The resolution is so high that, even spectral M stars (low mass dim red stars) and the even dimmer brown dwarfs (multiple Jupiter mass objects that lack sufficient mass to compress their core enough to initiate fusion), can be seen in the visible spectrum. In fact, the first brown dwarf binary is possibly discovered in this observation. Check out moderately sized images and the full story here. Or grab the image in its full sized glory of 18000x18000 pixels. The full size image has sufficient resolution to make a fine 12ftx12ft print wallpaper (in 300 dpi), according to my friend in photography. 12ftx12ft print wallpaper is much too large, I but think 5ftx5ft of this image in print is splendid enough...ahhhh, beauty isn't it?
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Old 2006-01-12, 03:51   Link #2
Kamui4356
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The images taken by the hubble never fail to amaze me.

It's a shame it's future is so uncertain. Though even if NASA does decide to do a repair mission, it won't last forever. I can only hope they seriously consider building a replacement for the hubble. It would be a shame to be left without such a vital tool in our quest to understand the universe.
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Old 2006-01-12, 04:25   Link #3
Chronissz
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Quote:
Originally Posted by Kamui4356
The images taken by the hubble never fail to amaze me.

It's a shame it's future is so uncertain. Though even if NASA does decide to do a repair mission, it won't last forever. I can only hope they seriously consider building a replacement for the hubble. It would be a shame to be left without such a vital tool in our quest to understand the universe.
I was reading through the site thinking just that, and I saw this near the end of the page:

Quote:
Plans are still underway for the James Webb Space Telescope, Hubble's successor, which would be launched in 2011. JWST will be designed to view objects in visible light and infrared, and its mirror will have six times the area of Hubble's mirror. Its goal is to study the first stars and galaxies that formed in the early universe. JWST will operate 1 million miles (1.5 million km) away from the Earth, and will not be serviceable from orbit. Learn more about JWST.
The link leads to here: http://jwstsite.stsci.edu/ ,

Quite an ambitious project, its kind of worrisome because unlike the Hubble, we wont be able to service it once it's put out in space, but the ability to view passed the obsticles that have always stood in our way, and truly see into deep space is an amazing feat. I've got my fingers crossed for it, but I can foresee a lot of problems that could easily arise to stop their progress, not to mention ruin it entirly. Imagine if they pulled a Hubble type mistake on this one, and its all the way at the moon.
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Old 2006-01-12, 05:23   Link #4
Kamui4356
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Quote:
Originally Posted by Chronissz
I was reading through the site thinking just that, and I saw this near the end of the page:



The link leads to here: http://jwstsite.stsci.edu/ ,

Quite an ambitious project, its kind of worrisome because unlike the Hubble, we wont be able to service it once it's put out in space, but the ability to view passed the obsticles that have always stood in our way, and truly see into deep space is an amazing feat. I've got my fingers crossed for it, but I can foresee a lot of problems that could easily arise to stop their progress, not to mention ruin it entirly. Imagine if they pulled a Hubble type mistake on this one, and its all the way at the moon.
Now that you pointed it out, I had heard of this, but I didn't realize it gotten this far. I thought it was just a proposal, not an actual project. Thanks for pointing it out. Great news indeed. Unfortunately, that site seems to be a bit out of date. I did a search and found this though: http://www.jwst.nasa.gov/ According to that site, the launch has been pushed back to june 2013 at the eariliest... A shame...

Hopefully it'll prove to be a worthy successor to the hubble. Looks like it'll be a long wait, but the images this should be capable of will make it worthwhile.
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Old 2006-01-12, 05:32   Link #5
Kensuke
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Quote:
Originally Posted by Muir Woods
I remember there was an astronomy thread, so I searched the forums for astro/astronomy but did not find it. Perhaps it was lost due to the hack incident. Hence, here's a new thread to have casual or critical discussions related to astronomy. Anyways, the news I want to bring is:
I don't remember that there ever was specific astronomy thread, but there was couple astronomy related threads about recent events.
Like "tenth planet" http://en.wikipedia.org/wiki/UB313

Even thought Hubble had plenty of troubles, it has expanded our view of universe more than any other single instrument. But maybe it is better to put money to new telescope rather than trying to maintain the old (if it is going to be replaced anyway), NASA is running short of funds, I believe. Also, I don't believe that any of the current manned spacecrafts can reach it, if it is going to be placed 1,5 million km from Earth.

But the new shuttles maybe ready at that time too.
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Old 2006-01-12, 08:15   Link #6
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After watching Twin Spica few days ago, the question pop into my mind. Is it true Spica are actually 2 stars? From reference book I only know it was part of Virgo constelation and also known as Alpha Virgo. I'm just wondering if anyone know more?
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Old 2006-01-12, 16:24   Link #7
Kensuke
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Yes, Spica is twin star system. I had to dig some information:

http://en.wikipedia.org/wiki/Spica
http://www.glyphweb.com/esky/stars/spica.html

Looking that data, Spica makes our Sun look very puny.
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Old 2006-01-13, 10:12   Link #8
Secca
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Quote:
Originally Posted by Kensuke
Yes, Spica is twin star system. I had to dig some information:

http://en.wikipedia.org/wiki/Spica
http://www.glyphweb.com/esky/stars/spica.html

Looking that data, Spica makes our Sun look very puny.
Spica is really amazing. I cannot imagine how twin stars looks like tho. I mean does one of them orbit around the other or they just spin simetrically opposite each other?

Having several moons orbiting your planet is probably interesting to see, but having two suns in the sky that would be quite a sight. Altho it'll be too hot to live in. ^^;;
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Old 2006-01-13, 18:28   Link #9
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They orbit each other, but not symmetrically, I don't know how things are in reality, but by looking their masses ( heavier star has a mass of 11 sun masses and the smaller one has a mass 7 sun masses), their common point of gravity is near the heavier star, so heavier star makes a smaller orbit. Like if you put a weight of 11 kg on the one end of stick and a weight of 7 kg on the other end, you have to lift it near heavier weight to keep it in balance.


Also, in a few days NASA is going to lauch a fastest probe ever, New Horizons will explore Pluto and other Kuiper Belt objects. Now it looks like the lauch is going to take palce January 17th. After the lauch probe will reach Moon's orbit in just 9 hours (it took couple of days for Apollo spacecrafts to reach Moon) and the probe will travel as fast as 21 km/s (47,000 miles per hour), but it still takes 9 years to reach Pluto, flyby is expected to take place 2015.

Website: http://pluto.jhuapl.edu/
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Old 2006-01-23, 20:11   Link #10
Catgirls
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National Geographic News has a nice little piece called Hubble's Top Ten Discoveries.

Quote:
Glowing in vibrant colors, planetary nebulae, such as this one, represent the death rattles of dying stars. These nebulae, which are not technically related to planets, are gas clouds forced outward by a dying star. According to NASA, "Hubble's keen 'eye' disclosed that planetary nebulas are like snowflakes: no two are like."
They're not the most visually appealing Hubble work, but significant none-the-less (sometimes ugly trumps beauty).

I've also been quite fascinated with the SOHO (Extreme ultraviolet Imaging Telescope) work:



-> http://umbra.nascom.nasa.gov/eit/EIT.html
-> http://soho.nascom.nasa.gov/
-> http://umbra.nascom.nasa.gov/eit/eit_full_res.html
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Old 2006-01-24, 11:21   Link #11
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Just a question, who was the first to discover that a stars position is not what we look at every night ? I mean the nearest star is light years away right ? so what we see every night at a star is the image of that star like many years ago... Can someone please tell me who was the first to discover that ? PLEASE BE 100% SURE!!
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Old 2006-01-24, 11:47   Link #12
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I’ll jump into this thread..
I want to buy one telescope of good quality. I am a beginner in astronomy, and want to make this one of my hobbies. I’ve heard that Meade has good models, so I went there and there are a lot of choices between reflectors and refractors. I’m willing to spend around U$ 300 on it. Any advices?
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Old 2006-01-24, 22:41   Link #13
Muir Woods
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Quote:
Originally Posted by Ero-Sannin
Just a question, who was the first to discover that a stars position is not what we look at every night ? I mean the nearest star is light years away right ? so what we see every night at a star is the image of that star like many years ago... Can someone please tell me who was the first to discover that ? PLEASE BE 100% SURE!!
I'd tentatively say, Tycho Brahe back in the 16th century. *Digging up old astronomy lecture notes* - The King of Denmark built him the Uraniborg, a huge and lavish observatory (and later, the Stellaburgi, another observatory), capable of measuring parallaxes down to an accuracy of 1 arcminute (1/60th of a degree), without the telescope. This was amazingly accurate back then. He surveyed celestial objects (including the supernova of 1572) and realized that these objects were much farther away than the Moon in measuring their parallaxes, or more precisely, the lack thereof. The stars are so far away that even the closest star have a parallax angle less than the accuracy of his observatories. He also saw that the heavens were not unchanging. But does his meaning "much father away" mean light years away? It's hard to answer the questions you phrased because they did not know the speed of light back then, much less a "light-year". It wasn't until a century later Olaf Roemer made the first rough measurement of the speed of light, and then later in the late 19th century that an accurate measurement of c was obtained in the laboratory. It's difficult to pin down one name to answer all your questions. Different people made different discoveries that contributed to our greater understanding of astronomy.
Quote:
Originally Posted by Loniat
I’ll jump into this thread..
I want to buy one telescope of good quality. I am a beginner in astronomy, and want to make this one of my hobbies. I’ve heard that Meade has good models, so I went there and there are a lot of choices between reflectors and refractors. I’m willing to spend around U$ 300 on it. Any advices?
I'll lay my bias out, I'm not much of an expert on telescope products. My interest in astronomy lies more in the quirkiest and most bizzare entities of the universe (eg. neutron stars/pulsars, black holes, quasars, gamma ray bursts...etc), and thus more theoretical. I've only owned one telescope in my life, and that is the crappy Simmon's model 6330 60mm telescope I had since 4th grade. I think your question would be best presented and answered in an astronomy focused site, such as this forum. Look into their forum and search for "buying telescope" or "beginner telescope" and you'll quickly find tons of topics on it. This thread may address that issue between a reflector vs refractor. Or this site has descriptions of recommended beginner's telescope. I'm sorry I couldn't help you more directly.
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Old 2006-01-25, 13:41   Link #14
Catgirls
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Ahh....more new planet goodness.

Scientists spot a new Earthlike planet
Quote:
‘Microlensing’ detects faraway world just 5.5 times bigger than our own


An artist's conception shows
the chilly planet.


Astronomers on Wednesday announced the discovery of what is possibly the smallest planet known outside our solar system orbiting a normal star.

Its orbit is farther from its host star than Earth is from the sun. Most known extrasolar planets reside inside the equivalent of Mercury’s orbit.

The planet is estimated to be about 5.5 times as massive as Earth and thought to be rocky. It orbits a red dwarf star about 28,000 light-years away. Red dwarfs are about one-fifth as massive as the sun and up to 50 times fainter. But they are among the most common stars in the universe.

(read...)
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Old 2006-01-25, 14:09   Link #15
Kamui4356
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Quote:
Originally Posted by Catgirls
Ahh....more new planet goodness.

Scientists spot a new Earthlike planet
I had just read about that before coming to the forum today. It's amazing they're able to detect planets that small now. It wasn't that long ago a planet had to be several times the size of jupiter to be detected.

Still, 5.5 times the earth's mass doesn't seem very "earthlike"... Though I guess it's a lot closer than the planets several times the mass of jupiter.
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Old 2006-01-25, 17:27   Link #16
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Quote:
Originally Posted by Kamui4356
Still, 5.5 times the earth's mass doesn't seem very "earthlike"... Though I guess it's a lot closer than the planets several times the mass of jupiter.
That's exactly what I thought, 5.5 ?!?!... just doesnt seem close.
Quote:
Since star alignments are unique events, a microlensing experiment can never be repeated.
Well, this kind off sucks >_<. I's like letting you taste a piece of cake but not allowing you to have the whole thing .
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Old 2006-01-25, 21:49   Link #17
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Quote:
Originally Posted by Kamui4356
Still, 5.5 times the earth's mass doesn't seem very "earthlike"... Though I guess it's a lot closer than the planets several times the mass of jupiter.
Currently, the only way to measure extra-solar planets is indirectly through the "wobble" of a star caused by the gravitational pull of the circling planet. There could very well be small planets like the Earth in several of the systems we have observed, but they won't be detectable with current technology.
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Old 2006-01-26, 02:22   Link #18
Muir Woods
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Quote:
Originally Posted by Cloudnine
Currently, the only way to measure extra-solar planets is indirectly through the "wobble" of a star caused by the gravitational pull of the circling planet. There could very well be small planets like the Earth in several of the systems we have observed, but they won't be detectable with current technology.
Not quite true. There is another, a bit more direct, way of detecting extra-solar planets, and that is through transit. If we are lucky enough to observe a star system who's equilateral axis is tilted edge on to us, a planet in orbit around the star may actually pass through in front the star, blocking its light. The difference in the star's bolometric luminosity may be measured. The amount of light blocked is proportional to the area blocked by the planet. In this way, we may be able to glean a rough idea of the size of the planet, assuming spherical shape.

For your interest (FYI):
We are able to measure differences in light intensity (photometry) quite accurately. Canada's MOST telescope (nicknamed "The Humble Space Telescope", and somewhat modeled after Spongebob Squarepants) does this job extremely well. Imagine the city of Toronto at night, and all the lights are on in that city. Turn off one light. MOST is able to measure that difference in intensity of light coming from Toronto. My astronomy 201 professor last semester, Dr. Jaymie Matthews, was actually involved in the construction of this telescope and heads the MOST project. He has a colorful background as an astronomer and professor...

The Hipparcos satellite, however, is able to measure parallaxes down to about the 1 milliarcsec range (1/1000ths of an arcsec [denoted "]; 1" = 1/60' [arcmin] =1/3600°). Let's put this in more tangible words. Imagine a person in front of you about 3 meters away. Wait ten seconds. In that ten seconds, that person's hair has grown about 1millarcsec with respect to your position, and the Hipparcos satellite can measure that angle.
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Last edited by Muir Woods; 2006-01-26 at 12:17.
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Old 2006-01-26, 13:34   Link #19
Catgirls
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Here's an interesting article that takes on some of the myths surrounding the Challenger shuttle disaster.

As a side note: I did watch this event "live". I was in Grad school at the time and had the day off. I was with two other college friends at my house and we were all watching the Challenger launch on CNN and saw the disaster that followed.

I'll quote the myth and a bit of the write up (no need to quote the enitre story). There's more to the story (and the myths), so follow the link below if you're interested. I found it to be quite interesting, but then I was very much alive at the time it happened.

------------------8<----------------

7 myths about the Challenger shuttle disaster
It didn't explode, the crew didn't die instantly and it wasn't inevitable

Myth #1: A nation watched as tragedy unfolded

Few people actually saw what happened live on television. The flight occurred during the early years of cable news, and although CNN was indeed carrying the launch when the shuttle was destroyed, all major broadcast stations had cut away — only to quickly return with taped relays.

Myth #2: Challenger exploded

The shuttle did not explode in the common definition of that word. There was no shock wave, no detonation, no "bang" — viewers on the ground just heard the roar of the engines stop as the shuttle’s fuel tank tore apart, spilling liquid oxygen and hydrogen which formed a huge fireball at an altitude of 46,000 ft. (Some television documentaries later added the sound of an explosion to these images.) But both solid-fuel strap-on boosters climbed up out of the cloud, still firing and unharmed by any explosion.

Myth #3: The crew died instantly

The flight, and the astronauts’ lives, did not end at that point, 73 seconds after launch. After Challenger was torn apart, the pieces continued upward from their own momentum, reaching a peak altitude of 65,000 ft before arching back down into the water. The cabin hit the surface 2 minutes and 45 seconds after breakup, and all investigations indicate the crew was still alive until then.

What's less clear is whether they were conscious.

Myth #4: Dangerous booster flaws result of meddling

The side-mounted booster rockets, which help propel the shuttle at launch then drop off during ascent, did possess flaws subject to improvement. But these flaws were neither especially dangerous if operated properly, nor the result of political interference.

Each of the pair of solid-fuel boosters was made from four separate segments that bolted end-to-end-to-end together, and flame escaping from one of the interfaces was what destroyed the shuttle.

Myth #5: Environmental ban led to weaker sealant

A favorite of the Internet, this myth states that a major factor in the disaster was that NASA had been ordered by regulatory agencies to abandon a working pressure sealant because it contained too much asbestos, and use a weaker replacement. But the replacement of the seal was unrelated to the disaster — and occurred prior to any environmental ban.

Even the original putty had persistent sealing problems, and after it was replaced by another putty that also contained asbestos, the higher level of breaches was connected not to the putty itself, but to a new test procedure being used. “We discovered that it was this leak check which was a likely cause of the dangerous bubbles in the putty that I had heard about," wrote physicist Richard Feynman, a member of the Challenger investigation board.

Myth #6: Political pressure forced the launch

There were pressures on the flight schedule, but none of any recognizable political origin. Launch officials clearly felt pressure to get the mission off after repeated delays, and they were embarrassed by repeated mockery on the television news of previous scrubs, but the driving factor in their minds seems to have been two shuttle-launched planetary probes. The first ever probes of this kind, they had an unmovable launch window just four months in the future. The persistent rumor that the White House had ordered the flight to proceed in order to spice up President Reagan’s scheduled State of the Union address seems based on political motivations, not any direct testimony or other first-hand evidence. Feynman personally checked out the rumor and never found any substantiation.

Myth #7: An unavoidable price for progress

Rationalizations that the disaster was the unavoidable price to be paid for pioneering a new frontier were self-serving cover-ups of those responsible for incompetent engineering management — the disaster should have been avoidable. NASA managers made a bad call for the launch decision, and engineers who had qualms about the O-rings were bullied or bamboozled into acquiescence. The skeptics’ argument that launching with record cold temperatures is valid, but it probably was not argued as persuasively as it might have been, in hindsight.

------------------8<----------------
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Old 2006-01-26, 16:23   Link #20
Kensuke
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That was indeed very interesting, before this I had thought that NASA was under some pressure to lauch the shuttle. I vaguely remember the disaster, of course I wasn't watching it live, but it was on the news as soon as it happened.

Sadly, accidents happens, no matter what you do, but not listening warnings and then learning nothing from the disaster and trying to cover their own asses is just low. What is more amazing that the Columbia disaster wasn't handled much better.
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