For close stars, the information we are now receiving is only a few years old. For the most distant stars in our observable universe, the information we are now receiving is billions of years old. For these distant stars, it is quite likely that they look very different from what we see in the light that we are now receiving. However, there is no way for us to know the present state of a star or for the present state of a star to affect us in any way.
That means the light hitting your eye tonight has been traveling for 8. Put another way: When you look at Sirius tonight, you see it as it was 8. As you look at more distant objects, the effect becomes bigger and bigger. The stars of the Big Dipper range from 60 to light years away. That is your birth star—the one whose visible light is the same age you are. When you look at that star tonight, you see it as it was at the time of your birth.
There is a birth star for everyone roughly if you are more than 4 years old. The Andromeda Galaxy is the most distant object readily visible to the naked eye. It is 2. The light from it that we see right now is 2. We are therefore seeing the Andromeda Galaxy as it was at a time long before modern humans existed! This seems really fast, but objects in space are so far away that it takes a lot of time for their light to reach us.
The farther an object is, the farther in the past we see it. Our Sun is the closest star to us. It is about 93 million miles away. So, the Sun's light takes about 8. This means that we always see the Sun as it was about 8.
The next closest star to us is about 4. All of the other stars we can see with our eyes are farther, some even thousands of light-years away. Stars are found in large groups called galaxies. Astronomers at an international conference of top cosmologists at the Kavli Institute for Theoretical Physics in Santa Barbara, California, in July were puzzling over studies that suggested different ages for the universe. They were looking at measurements of galaxies that are relatively nearby which suggest the universe is younger by hundreds of millions of years compared to the age determined by the cosmic microwave background.
Related: 7 Surprising Things About the Universe. In fact, far from being The conclusions are based on the idea of an expanding universe , as shown in by Edwin Hubble. This is fundamental to the Big Bang — the understanding that there was once a state of hot denseness that exploded out, stretching space. Indeed, the Planck team determined that the expansion rate was That means there is a difference between the measurement of how fast the universe is expanding today and the predictions of how fast it should be expanding based on the physics of the early universe, Riess said.
It's leading to a reassessment of accepted theories while also showing there is still much to learn about dark matter and dark energy , which are thought to be behind this conundrum. A higher value for the Hubble Constant indicates a shorter age for the universe. A constant of It's a mismatch that suggests, once again, that HD is older than the universe.
It has also since been superseded by a study published in the journal Science that proposed a Hubble Constant of Matthews believes the answers lie in greater cosmological refinement.
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