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Why are Cepheid variable so important for measuring long distances in the universe?
Wiki User
∙ 15y ago
The perceived brightness of an object with known brightness can be used to gauge distances. Cepheid variables are known to have a brightness directly related to their period. Which means that if we know the period of the Cepheid variable, we know what its brightness is, and can use it to gauge the distance to the stellar group the Cepheid is part of.
Wiki User
∙ 11y ago
Wiki User
∙ 10y agoI'll answer half way to your Questions, Ancient people, they had chart stars using only inks and papers without any aids of Telescope or Hubble's and they actually see the same constellations of Stars as me, your RM 10.00 per day astronomer. If they see no changes and I've seen no changes, then How can you had seen changes?.
Next, yes there are dead stars and dying stars all over the Universe because like any creatures when it run out of fuel it'll dying and die , but if you want to know How a star begin?. then my answer would be the same as to any 7 years old boys, Stars came from dark places, some dark places are small and some dark places are very big.
And now, some inside to my books, I've read about your exploded stars and I think, I did examine some free pictures and I thank you for the free pictures, but I've found some errors on Einstein's Relativity Theory and I will not give it for free.
Also just for heads up, the answer are scarier and much worrying then most would want to admit.
Wiki User
∙ 9y agoThese two methods are used to find the distance of stars. Parallax was used by Bessel in 1838 to discover the distance to the star 61 Cygni. Parallax is the tiny movement of a nearby star against the background stars, that happens as the Earth moves round the Sun.
The lack of parallax used to be taken as a sign that the Earth does not move; however there always was parallax but it was too small to be measured until 1838 when it was discovered by Bessel. Suddenly everyone realised how unimaginably far away the stars in fact are, but that was only a first step.
In 1912 Miss Henrietta Leavitt at the Harvard College Observatory made the next important discovery. All Cepehid variables (whose prototype star is Delta Cephei) have a steady and reliable brightness curve. Some local Cepheid variables had already had their parallax and distance measured, and Henrietta started observing more distant Cepheid variables in the Magellanic Clouds.
Henrietta knew that some Cepheid variables take longer to go through their cycle than others. But the ones in the Magellanic Clouds showed a definite trend that took her interest. She knew that all the stars in the Magellanic Clouds are about the same distance away from us, and she found that the brighter ones take longer to cycle. She reasoned that their apparent magnitude must be linked to their absolute magnitude (intrinsic brightness). She produced a graph that related the period of variability to the absolute magnitude - called the Period-Luminosity curve.
It didn't take long for people to realise that this was a great new yardstick for finding the distances to much more distant stars and galaxies. All you had to do was to find a few Cepheid variables in the Andromeda Nebula, and you would know how far away it is. That way it was discovered that it's over a million light-years to that nebula.
Later the Red Shift was discovered for measuring really distant objects, but the measurements are all based on this logical progression of measurements, each one standing on the previous one.
Wiki User
∙ 7y agoFor any object, you need to compare the real brightness ("absolute magnitude") with the apparent brightness ("apparent magnitude"). Specifically in the case of Cepheids, the absolute magnitude can be deduced from its period.
Wiki User
∙ 13y agoThese stars have been used to calculate the distance to most galaxies in which a cepheid is present.
Wiki User
∙ 15y agoTheir luminosity can be inferred from their period.
Wiki User
∙ 14y agothe distance to most galaxies in which a cepheid is present.
Wiki User
∙ 9y agoA Cepheid is a type of star that varies in size and density. The link between a Cepheid variable's luminosity and pulsation period makes them valuable for measuring distances in astronomy.
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Cepheid variable stars have been used to determine the?
1)placing cosmological constraints on the expansion of the Universe through the determination of distances to galaxies 2)to measure many characteristics of our galaxy and our relationship to it
When was the universe discovered?
In 1929 Edwin Hubble, working at the Carnegie Observatories in Pasadena, California, measured the redshifts of a number of distant galaxies. He also measured their relative distances by measuring the apparent brightness of a class of variable stars called Cepheids in each galaxy. When he plotted redshift against relative distance, he found that the redshift of distant galaxies increased as a linear function of their distance. The only explanation for this observation is that the universe was expanding.Once scientists understood that the universe was expanding, they immediately realized that it would have been smaller in the past. At some point in the past, the entire universe would have been a single point. This point, later called the big bang, was the beginning of the universe as we understand it today.The expanding universe is finite in both time and space. The reason that the universe did not collapse, as Newton's and Einstein's equations said it might, is that it had been expanding from the moment of its creation. The universe is in a constant state of change. The expanding universe, a new idea based on modern physics, laid to rest the paradoxes that troubled astronomers from ancient times until the early 20th Century.Properties of the Expanding UniverseThe equations of the expanding universe have three possible solutions, each of which predicts a different eventual fate for the universe as a whole. Which fate will ultimately befall the universe can be determined by measuring how fast the universe expands relative to how much matter the universe contains.The three possible types of expanding universes are called open, flat, and closed universes. If the universe were open, it would expand forever. If the universe were flat, it would also expand forever, but the expansion rate would slow to zero after an infinite amount of time. If the universe were closed, it would eventually stop expanding and recollapse on itself, possibly leading to another big bang. In all three cases, the expansion slows, and the force that causes the slowing is gravity.A simple analogy to understand these three types of universes is to consider a spaceship launched from the surface of the Earth. If the spaceship does not have enough speed to escape the Earth's gravity, it will eventually fall back to Earth. This is analogous with a closed universe that recollapses. If the spaceship is given enough speed so that it has just enough energy to escape, then at an infinite distance away from the Earth, it will come to a stop (this is the flat universe). And lastly, if the ship is launched with more than enough energy to escape, it will always have some speed, even when it is an infinite distance away (the open universe).
What is the most variable abundance in the atmosphere?
The most variable abundance in the atmosphere is Water Vapour and Ozone
What is the variable of a cloud?
c
A person weighs 100 pounds and earth weighs 16.6lb on the moon which variable is the independence variable explain why?
The independent variable is the person's mass, since the mass of an object is constant regardless of gravitational force.
What is a variable being measured?
The variable that you are measuring is the dependent variabledependant variable
What is the variable measuring the result of an experiment?
Dependent variable!!
Independent variable in measuring heart rate?
Time is the independent variable.
Independent and dependent are types of this in science?
Variables. A dependant variable is dependent upon the independent variable - it is usually the unit that you are measuring eg mL, degrees, m etc.An independent variable is what youa re measuring - generally a question, object etc.When writing an experiment, it is important to identify these variables, as teachers like to mark them.
Cepheid variable stars have been used to determine the?
1)placing cosmological constraints on the expansion of the Universe through the determination of distances to galaxies 2)to measure many characteristics of our galaxy and our relationship to it
Is perception a discreet or continuous variable?
It would depend what aspect of perception you are measuring and how you are measuring it.
What is an across variable?
An across variable is a variable whose value is determined by measuring a difference of the values at the two extreme points of an element.
What is a dependet varible?
dependent variable is what you are measuring in an science experiment
How is independent and dependent variables measured?
Independent Variable is what you are CHANGING and Dependent Variable is what you are MEASURING ! get at me on aim if i helped Gurlsofly5
When the process of arriving at a measure of a concept or variable is referred to as replication?
The process of arriving at a means of measuring a concept or a variable is ...
What are the independent dependent and control variables?
The independent variable is the thing you are changing/varying. The dependent variable is the thing you are measuring. This variable should be affected by the independent variable. Control variables are anything that must be kept constant. If there are any other factors which affect the dependent variable, then these need to be controlled so that they do not have any significant effect (basically ensuring that you are actually measuring the effects of the independent variable).
In a experiment why is it important to have one manipulted variable?
its important to have a manipulative variable so you have at least one variable that will reapond to what you do to it
