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Galaxies
Galaxies are large systems of stars and interstellar matter, and they contain billions of stars. Our own galaxy, the Milky Way, has 200 to 400 billion stars, and there are over one billion known galaxies. Questions that have to do with galaxies in general and specific galaxies are perfect for this category!
2,392 Questions
As that's the prevailing view, pretty much everybody except Harlow Shapley, who thought the Milky Way was the major feature of the universe and all the "nebulae" were its satellites.
In the "Great Debate" (in the year 1920) between Harlow Shapley and Heber Curtis on this subject, it was Curtis who argued that many of the nebulae were outside our Galaxy.
So, the answer you want is probably "Heber Curtis".
"Great dog" and "Lesser dog". Except in Latin, so it's Canis Major and Canis Minor.
What is the difference between a flocculent spiral galaxy and a grand design spiral galaxy?
A grand design spiral galaxy (like Whirlpool Galaxy) has prominent and well defined spiral arms, whereas a flocculent galaxy (like Sunflower Galaxy) has short segments of spiral structure, "fluffy" in appearance, but without the dramatic well defined spiral arms of a grand design spiral.
The Galactic halo is the spherical region surrounding the disk of a spiral galaxy which contains globular clusters and reddish population II stars.
How does the diameter of the disk of the Milky Way Galaxy compare to its thickness?
The Milky Way galaxy is 100,000 light years across and 1,000 light years thick.
But the really fun part is that the Milky Way is all around us. We are right inside
the Milky Way; it is our home galaxy. The Milky Way is not far away from you.
You are a part of it.
How bright was the crab nebula?
from sci-tech encyclopedia http://content.answers.com/main/content/img/McGrawHill/Encyclopedia/images/CE166300FG0010.gif The Crab Nebula is the remnant of a tremendous stellar explosion witnessed by Chinese astronomers in 1054. The explosion, called a supernova, occurred at a distance of about 2000 parsecs from the Earth (1 parsec = 1.9 × 1013 mi = 3.1 × 1013 km = 3.26 light-years). The Crab now consists of three components. At the heart of the nebula is what is left of the core of the Crab's giant stellar progenitor. This neutron star has twice the mass of the Sun concentrated into an object only about 20 km (12 mi) across, giving it a density of 109 tons per cubic centimeter. The neutron star is spinning at 30 times a second, whipping its powerful (108 tesla) magnetic field around with it. Radiation formed in this extreme environment is concentrated into two intense beams directed away from the neutron star's two magnetic poles. As these beams sweep past the direction of the Earth like the beam from a lighthouse, the star appears to wink on and off, earning it the name "pulsar." The Crab pulsar has been seen in all parts of the electromagnetic spectrum from gamma rays through radio waves. The Crab pulsar's rotational period is slowing by 34 nanoseconds a day, and as it slows it loses 100,000 times more power than is radiated away by the Sun. Most of this energy is carried away from the pulsar by a wind of electrons and positrons moving at close to the speed of light. The wind feeds a vast cloud of highly relativistic particles. This cloud is called the Crab synchrotron nebula because, as the particles spiral through the nebula's magnetic field, they give off the sort of radiation emitted by a synchroton particle accelerator. . The third component of the Crab is a complex of filaments made up of gas ejected by the explosion itself (see illustration). The filaments are ionized by ultraviolet radiation from the synchrotron nebula, causing them to glow like the gas in a fluorescent light bulb
What holds the galaxies and solar systems together?
Galaxies are held together by gravity. So are Solar Systems. In the case of galaxies, and galaxy clusters, it isn't entirely clear what type of masses provide this gravity - the amount of known matter is simply too small, by a factor of 5-10. For more information, do some reading on "dark matter".
Does Every Galaxy Merge Eventually?
The answer to this is we do not know but it looks unlikely.
The expansion of the universe appears to be speeding up. Local Galaxies might merge into larger galaxies but these galaxies will expand faster and faster away from each other.
What is the nearest rich cluster of galaxies?
The nearest cluster of galaxies is the "Virgo Cluster" discovered by Charles Messier in 1784. The Virgo cluster lies at/near the center of the Supercluster we belong to - also called the "Virgo Supercluster".
Our "Local Group" (comprising of The Milky way, Andromeda, and another 25-30 smaller galaxies) is part of the Virgo Cluster.
The center of the Virgo cluster is at a distance of about 18 Mpc (Mega parsecs) approx 60 Million lightyears from us [which translates to a 'redshift' of only z=0.004]. Ain't the universe huge?
Note: There are quite a few 'groups of galaxies' between us and the center of Virgo Cluster.
It would be inactive, thus considered a "pure galaxy". This "pure galaxy" is also
considered to be an elliptical galaxy (E7). It would be inactive because no alien
gravitational forces have affected the relatively stable system.
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How many stars are in galaxies millions or billions?
Billions at least, in the large galaxies.
Obviously it depends on the size of the galaxy.
It is estimated that in our Galaxy there are at least 100 billion and perhaps as many as 400 billion stars.
Many galaxies are same sort of size as ours and some are much bigger.
However, there are a lot of small "dwarf galaxies"
The smaller dwarf galaxies have millions rather than billions of stars.
What is one way that an elliptical galaxy differs from the other types of galaxies?
Elliptical galaxies are large blob shaped galaxies that most galaxies will eventually look like. Elliptical galaxies are what happens when two or more large galaxies collide and coalesce.
How old is the Milky Way galaxy?
It's very difficult to define the age of the Milky Way Galaxy, but the age of the oldest star in the Galaxy yet discovered is estimated to be about 13.2 billion years.
The Universe is believed to be around 13.73 billion years old.
Not according to that theory (not really needed for this),
but the sun is about 5 billion years old (as is the whole solar system)
and Earth has an iron core - which we know came from prior stars (lots of them)
which gives us an other couple of billion years ...
so you come up with a minimum of about 10 billion years
(and a max of 13 ... which does come from "big bang calculations").
In satellite beams what is the difference between FSS and BSS?
BSS = Broadcasting Satellite Service (12.2->12.7Ghz) -- Usually for home reception. Uses circular polarization.
FSS = Fixed Satellite Service (11.7->12.2Ghz) -- Usually for commercial reception. Uses linear (horizontal/vertical) polarization.
Can there be a light that does not produce heat?
LED .. Light Emitting Diodes , they're known for their very low energy consumption and they do not emit much heat. As of now , there is no kind of light which does not produce heat . But , LED's fit in as very efficient light emitters which produce very less heat. Also LED's have a life line which is way greater when compared to normal lights.
Hope this helps =)
What is at the center of Seyfert galaxies?
Nothing special - Just like most large galaxies, they are thought to have a super massive black hole at the centre of the galaxy.
Prelox are the tablets for male sex enhancement marketed by galaxy pharma in pakistan
Yes. Every star that is visible to the naked eye is in the Milky Way galaxy. You need astonishingly powerful telescopes to distinguish even the largest and brightest stars in nearby galaxies.
Is the Earth located in a spiral galaxy called the Milky Way?
The Earth and its parent star, the Sun, are located within the Milky Way galaxy, so named by the inhabitants of Earth. The Milky Way galaxy is believed to be a larger-than-average barred spiral galaxy. There may be as many as 300 billion stars in our Milky Way, maybe many more.
The nearest galaxy of such enormous class we have named the Andromeda galaxy. It is roughly 2.5 million light-years distant. But there are two tiny galaxies that orbit our own Milky Way; the Large Magellanic Cloud and the Small Magellanic Cloud. They are named for Ferdinand Magellan, the first white dude from the northern hemisphere to make a big noise about them.
The Earth is located in the "Orion arm" of our galaxy, somewhere between half and two-thirds of the way out from its hellish center. In a galaxy thought to be 100,000 light years across, we find ourselves in the lucky "habitable zone" of one of its spiral arms.
Why does your galaxy from your view not look like other sprial galaxies?
Good question; why can't you see your own face without using a mirror?
Answers to BOTH questions; because we're INSIDE our faces - and inside our galaxy - and we can't see the whole thing. From the astronomy perspective, it's even worse; imagine being a cell in one of your tonsils, and trying to see your entire body. Our Sun is about 2/3 of the way out one of the spiral "arms", and we can't see the whole thing.
You may be describing a "barred spiral" galaxy.
Is a local group a group of galaxies?
Yes. Our local group of galaxies is made up of 3 larger galaxies (milky-way, Andromeda and M33) and several smaller or dwarf galaxies.
The description of "wobble" really doesn't paint a picture that's clear enough to
suggest what you're actually seeing.
If you see anything in the sky that appears to move with respect to stars, then
that object is either the sun, or else it's not a star. It could be a planet, an asteroid,
a comet, a meteor, the Earth's moon, or an artificial satellite.
"Southeast of the Big Dipper" also doesn't help. The Big Dipper ... and every other
pattern of stars ... either rotates half-way around the pole or else crosses the entire
sky, every night.
What is the difference between dimensions and universes?
The use of the word "dimension" to describe alternate worlds in fiction is something of a misnomer; it would probably be more accurate to describe them as alternate universes. In science and mathematics a dimension is a set of coordinates used to specify a point within it. We observe 4 dimensions: 3 perpendicular dimensions of space and a fourth dimension of time.
