Astronomy Trivia Challenge: Can You Answer These Questions About the Night Sky?

In summary, this conversation is about an astronomy Q&A game where players take turns asking and answering questions. The rules are that a question must be answered correctly within 3 days or a new question is posted. If the person who posted the question does not respond within 2-3 days, the first person to answer correctly can then post their own question. The first question asked is about the brightest star in the Northern Sky, with the correct answer being Sirius. The game then continues with questions about other astronomical topics such as supermassive black holes, energy generation in stars, and the length of Pluto's orbit. The conversation also includes some discussion about the rules and format of the game, as well as some jokes and personal anecdotes from the
  • #36
Thx...in what constellation is the star named Alkalurops ?
 
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  • #37
Originally posted by bogdan
Thx...in what constellation is the star named Alkalurops ?

The Plowman, I think his name is Buotus, although that's probably not the spelling!
 
  • #38
Boötes, I'm just correcting LURCH's spelling.
 
  • #39
That's correct but I'm sure you'd rather wait for bogdans confirmation... right?


By the way welcome to everyone from the old forums and new!
 
  • #40
Alkalurops or Inkalunis or Icalurus or Clava or Venabulum... I guess you mean this star, well, it is in Bootes, in fact, it's Mu 1 Bootis. Alkalurops means the "shepherd's crook".
 
  • #41
Bootes is the correct answer...
So...Lurch...it's your turn...thx to cragwolf...
I'm sorry Philosopher...maybe next time...
 
  • #42
awwww...shoot! I'll try next time too then.

M.
 
  • #43
Good we always like more people coming to join this therad welcome to PF


Ok Lurch ask away
 
  • #44
Okey-Dokey,

Fortunately for astronomers,our solar system is currently moving into a rather large, empty portion of the galaxy. Sort-of like a "clearing" in the Milky Way Forest.

To what cause do astronomers attribute this clearing?
 
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  • #45
Cosmic Acceleration
 
  • #46
http://www.anzwers.org/free/universe/2000lys.html

Lurch, you say solar system is currently entering a clearing.

I found this map of the Orion Arm (which is the small arm we are in)

It is a projection on the galactic plane with the the sun in the center and all the Hipparchos cataloged stars out to 2000 ly.

the sun's motion is to the right of the map towards the stars marked cygnus, I believe.

there is also a link there to a largerscale map of the Orion Arm, everything out to 5000 ly.

maybe these maps will help someone answer the question.

What you say is interesting and makes me wonder what the size and distance of this clearing is and what is the timescale of our entering it.
 
  • #47
Fortunately for astronomers,our solar system is currently moving into a rather large, empty portion of the galaxy. Sort-of like a "clearing" in the Milky Way Forest.
I will take a stab from memory without any internet site to point to.

The distances mentioned at the site above about the Orion Arm are very small distances compared to the size of our galaxy. The Sun, with us, happens to be located at the "inside edge" of the Orion arm with relatively little between us and the Sagittarius arm, the next one in toward the galactic center. We are ~33,000 light years from the galactic core with this "clear space" allowing us to see across to the Sagittarius arm and the galactic core behind, with radio and infrared.

However, contrary to popular belief, a spiral arm does not make a full rotation of a galaxy intact as an arm with its general size and shape. Our Sun, will rotate a bit faster than the "rest" of the Orion arm as the stars farther from the core of the galaxy start to lag behind. The sun will make one full revolution in about 250 million years, and in that time the Orion arm, and all others, will dissapate as new spiral arms form from newly-formed stars and re-distribution of gas and dust. In other words, we will be moving more and more into an "empty space" between spiral arms as a few (million) years pass.
 
  • #48
Isn't it odd how in science a long time is a short time? Like on the radio (it was on a regular music station actually. I was quite surprised) They were saying that in only a few million years the Earth will begin to get colder because the sun will be changing into a Red Giant. ONLY A FEW MILLION YEARS FOLKS! PUT IT ON YOUR CALENDER!

(psst lurch did I get it right?)
 
  • #49
Nope, yer thinkin' too big; occupational hazard in astronomy. I'm talking about the small (on the cosmic scale) clearing in our neighborhood of this galaxy.
 
  • #50
Oh I see. Or I will. I will think this over again. Cosmic acceleration would be the whole galaxy so I need something smaller...hmm
 
  • #51
Nope, yer thinkin' too big; occupational hazard in astronomy. I'm talking about the small (on the cosmic scale) clearing in our neighborhood of this galaxy.
Ok, another guess. If you are talking on a small scale, we happenen to be located in a large area of nearby star-forming regions. As the stars form and the dust and gas condense, we will be in, and looking through, a "clearer" area of space to whatever is beyond.
 
  • #52
A supernova. Just a guess, though.
 
  • #53
Hmmm I don't think it is a supernova but I got it wrong so I guess I wouldn't know...

So if cosmic acceleration is too big and that is the whole galaxy then...

There is something similar too cosmic acceleration occurring in our own galaxy, which is pushing all the solar systems away.

(which could be caused by the supermassive black hole at the center of our galaxy)
 
  • #54
Originally posted by cragwolf
A supernova. Just a guess, though.

Darn good guess, Crag. As among the many "lucky accidents" of our kind of life developing on Earth, this supernova is believed to have taken place at sufficient distance so as not to bombard us with so much radiation that it sterrilized the surface, yet close enough to clear away the area into which ur system was about to pass, thus elliminating much of the debris that many exogeologists believe might prevent life from forming.

So I guess astronomers doubly benifit from that blast; it provides them with a clearer view, but it also permitted them to come into existence.

Your go Cragwolf.
 
  • #55
There have been many "nearby" supernovae in recent times cosmologicaly speaking. Did you have something particular in mind, or just a generic event of many that could have been the answer to your question?

Questions on this thread should probably be more specific than just "something I had in mind", I think.
 
  • #56
Hmmm I don't think it is a supernova but I got it wrong so I guess I wouldn't know...


Good thing I said that! Wow I got something wrong twice in one question!
 
  • #57
OK, my turn. The globular cluster system of the Milky Way (and indeed, of many galaxies) is comprised of two distinct populations. What is the main observational parameter which distinguishes these two populations? The answer isn't size or luminosity, but that should give you an idea of what I mean by observational parameter.
 
  • #58
I'm making a wild guess... mass?
 
  • #59
Open and globular clusters. Where open clusters are typically young metal rich pop I stars and globular are of older low-metal pop II stars.
 
  • #60
Color. Either observational or spectral. Older globulars are more orange-red, indicating population II stars, and any younger globulars would contain second generation stars of population I colored more toward the blue-white end of the spectrum. This would also show in the different types of Cepheids found in older verses newer globulars.
 
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  • #61
Crag are you here? can you confirm the answers...?
 
  • #62
labguy's answer is more or less correct. Mostly, astronomers speak of a bimodality in the metallicity distribution of globular clusters in our Galaxy (metallicity tends to scale roughly linearly (*) with colour, so the two terms tend to be interchangeably used). There appears to be two populations of globulars within the Milky Way: a metal-poor population ([Fe/H ~ -1.5] associated with the galactic halo, and a metal-rich population ([Fe/H] ~ -0.5) associated with either the galactic disk or bulge. The metal-rich globulars seem to be roughly 2 billion years younger (on average) than the metal-poor globulars (but note, this is roughly the same as the uncertainty in the ages of globular clusters). One theory of globular cluster formation is that the younger, metal-rich clusters were formed during a merging episode (i.e. when the host galaxy merged with another galaxy), and the older, metal-poor globulars formed during the formation of the host galaxy itself. Observations of mergers show very young globulars.

(*) But in recent years this assumption of linearity has been challenged.
 
  • #63
Erm, I said metal.
 
  • #64
Erm, I said metal.
Yes, you did. But, you were also making the distinction between open and globular clusters, while the question was only about globulars.

I had a question, before the PF format changed, that I don't think was ever answered.(?)

QUESTION:
In the Crab Nebula (Supernova Remnant),
(1) What is particularly rare about the light that we can see?
(2) What causes this rare property?
(3) What is the name given to this type of light (EM radiation)?
 
  • #65
The pulsar produces synchrotron radiation, which is what partially makes the nebula glow. This is caused when charged particles, I think deutrons, sprial around a magnetic field. The photons are then emitted from the poles of the mag field.
 
  • #66
The pulsar produces synchrotron radiation, which is what partially makes the nebula glow. This is caused when charged particles, I think deutrons, sprial around a magnetic field. The photons are then emitted from the poles of the mag field.
Synchrotron radiation is right for the name, but I need two more specific answers for the rest. Right track, though.
 
  • #67
Labguy asked:
QUESTION:
In the Crab Nebula (Supernova Remnant),
(1) What is particularly rare about the light that we can see?
(2) What causes this rare property?
(3) What is the name given to this type of light (EM radiation)?

(1) We see light in all known forms/frequencies and it does not follow the blackbody radiation curve, increasing toward lower frequencies rather than toward high. (It is said to be "nonthermal".)
(2) The fastest known Pulsar, near the middle of the nebula.
(3) Synchrotron Radiation.
 
  • #68
1) It is polarized; different regions have different polarizations.
2) Electrons spiraling around regions of uniform magnetic field.
3) Synchrotron radiation.

- Warren
 
  • #69
Originally posted by chroot
1) It is polarized; different regions have different polarizations.
2) Electrons spiraling around regions of uniform magnetic field.
3) Synchrotron radiation.

- Warren
This one is correct. The main "property" I was looking for was that this type of EMR is polarized.

Your question, Chroot.
 
  • #70
Hmmm... my turn... I got to think of a good one. :)

- Warren
 

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