Wysiwyg
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The death of a star in a galaxy some 240 million light years away produced the brightest supernova ever viewed.
The star is thought to have been massive -- more than 100 times the weight of our own sun.
when our sun turns into a red giant in a few billion years we will actually drift further away from the sun, because as the sun loses mass by burning its fuel, the gravity holding the earth to its orbit becomes weaker, so we drift further and further out. gravity is a by product of mass, the suns mass is made up of hydrogen, and as the sun burns hydrogen it loses mass. therefore its gravity becomes weaker over time. however as the sun becomes a red giant it expands and will swallow the orbits of mercury and venus, and possibly earth so its the same outcome as drifting closer, just a different mechanism
http://www.tenthdimension.com/medialinks.php
Anyone know how they know it's 240 million light years away
(clever dudes)
I guess just becos it doesn't fit into the scheme of things any closer than that
PS speed of light unchanged - red shift determines speed etc
Hi 2020hindsight,
I often wonder about the universe as to how many planerts there are out there waiting to be discovered. I imagine that within the next century or so there may well be another 20 planets or so discovered.
.For galaxies more distant than the Local Group and the nearby Virgo Cluster, but within a thousand megaparsecs or so, the redshift is approximately proportional to the galaxy's distance. This correlation was first observed by Edwin Hubble and has come to be known as Hubble's law. Vesto Slipher was the first to discover galactic redshifts, in about the year 1912, while Hubble correlated Slipher's measurements with distances he measured by other means to formulate his Law. In the widely accepted cosmological model based on general relativity, redshift is mainly a result of the expansion of space: this means that the farther away a galaxy is from us, the more the space has expanded in the time since the light left that galaxy, so the more the light has been stretched, the more redshifted the light is, and so the faster it appears to be moving away from us. Hubble's law follows in part from the Copernican principle.[49] Because it is usually not known how luminous objects are, measuring the redshift is easier than more direct distance measurements, so redshift is sometimes in practice converted to a crude distance measurement using Hubble's law
then there are calibrations like "red clump" (apparently) - gee I love wikipedia lolhttp://en.wikipedia.org/wiki/Cosmic_distance_ladder With few exceptions, fundamental distances are available only out to about a thousand parsecs, which is a modest portion of our own Galaxy. For distances beyond that, measures depend upon physical assumptions, that is, the assertion that one recognizes the object in question, and the class of objects is homogeneous enough that its members can be used for meaningful estimation of distance.
Almost all of these physical distance indicators are standard candles. These rely upon recognizing an object as belonging to some class, which has some known absolute magnitude, measuring its apparent magnitude, and using the inverse square law to infer the distance needed to make the "candle" appear at its observed brightness. Some means of accounting for interstellar extinction, which also makes objects appear fainter, is also needed. The difference between absolute and apparent magnitudes is called the distance modulus, and astronomical distances, especially intergalactic ones, are sometimes tabulated in this way.
Physical distance indicators, used on progressively larger distance scales, include:
Main sequence fitting, usually for open clusters of stars
Cepheids and novae
Individual galaxies in clusters of galaxies
The Tully-Fisher relation
Type Ia supernovae
Redshifts and Hubble's Law
It was basically a rough guess (20 planets). I don't have a scientific background )I only studied economics, politics and history at uni), but have always wondered what else is out there.Greggy,
I reckon that if you bet only 20 planets (of distant stars) that's a real safe bet
Think I've found how they measure distance - good enough it seems to just use red shift., i.e. the big bang expansion is well quantified that they measure distance by the speed at which the object is moving awat fromus ( making things appear a fraction redder) etc
http://en.wikipedia.org/wiki/Redshift
.
But please prove this assumption wrong if you know better
Anyone know how they know it's 240 million light years away
(clever dudes)
I guess just becos it doesn't fit into the scheme of things any closer than that
PS speed of light unchanged - red shift determines speed etc.
Don`t know for sure but probably a reflective thing , going on the speed of light..
Wik says that light travels at 1,079,252,848.8 km/h , which if multiplied by 8760 (the number of hours in a standard year) would mean that light would travel 9,454,254,955,488 kilometres in an earth year.
So knowing this we can calculate that 240 million light years is about (give or take a few metres) 2,269,021,189,317,120,000,000 km. away.This is not difficult to understand.A drive to your local shopping centre will help you understand these things.Good luck.
In reality I`m sure these years are approximations , the images are historical so what is happening now we won`t know for a long time , the further away they are.
Yep - here's an old post from "homework" thread. 300,000 km/sec (as measured way back when 1670 or some such - incredible in itself). PS the moon is a bit over a light second away.Don`t know for sure but probably a reflective thing , going on the speed of light..
...In reality I`m sure these years are approximations , the images are historical so what is happening now we won`t know for a long time , the further away they are.
and given that light travels at same speed towards us as away from us, (as I understand it) - give or take our respective velocities since - (let's assume we are each moving apart at similar speeds)- they would be simultaneously seeing us (approx) I guess for the first time - in whatever state we were in 240 million years ago. - in fact if they had a telescope they'd see some early Triassic dinasaurs, and first mammals and crocodiles - and modern coral - insects etcduring the 1670's, the Danish astronomer Ole Roemer was making extremely careful observations of Jupiter's moon Io. Roemer was able to calculate a value for the speed of light. The number he came up with was about 186,000 miles per second, or 300,000 kilometers per second.
Likewise NASAAlthough the SN 2006gy supernova is intrinsically about ten times as luminous than SN 1987A, which was bright enough to be seen by the naked eye, SN 2006gy was more than 1,400 times as far away as SN 1987A, and too far away to be seen without a telescope.[7]
Light curve of SN 2006gy (uppermost intermittent squares) compared with other types of supernovae.
Similarity to Eta Carinæ. Eta Carinæ (η Carinæ or η Car) is a highly luminous hypergiant star located approximately 7,500 light years from Earth in the Milky Way galaxy. Since Eta Carinæ is 32,000 times closer than SN2006gy, the light from it will be almost a billion-fold brighter. It is estimated to be similar in size to the star which became SN2006gy. Dave Pooley, one of the discoverers of SN2006gy, says that if Eta Carinæ exploded in a similar fashion, it would be bright enough that one could read by its light here on Earth nights, and would even be visible during the day time. SN2006gy's Apparent magnitude (m) is 15,[1] so a similar event at Eta Carinæ will have an m of about -7.5. According to astrophysicist Mario Livio, this could happen at any time, but the risk to life on Earth would be low.[8]
Astronomers think many of the first generation of stars were this massive, and this new supernova may thus provide a rare glimpse of how the first stars died. It is unprecedented, however, to find such a massive star and witness its death. The discovery of the supernova, known as SN 2006gy, provides evidence that the death of such massive stars is fundamentally different from theoretical predictions.
"Of all exploding stars ever observed, this was the king," said Alex Filippenko, leader of the ground-based observations at the Lick Observatory at Mt. Hamilton, Calif., and the Keck Observatory in Mauna Kea, Hawaii. "We were astonished to see how bright it got, and how long it lasted."
Quite easily.How can time not be a constant? The book had an example of how if you sat just outside of the event horizon of a black hole that time is warped so much that a year there would take the same time as 100 years here
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