- #1
SolidHelix
- 4
- 0
I was thinking, when we see headlines about new galaxy found to be oldest yet, or furthest away... is it possible that we could be seing some of these as earlier positions of previously found nearer objects?
SolidHelix said:OK, I understand... I was thinking hypothetically that if the said object was moving toward us, that since it was further away in the earlier position it would take the light longer to reach us and maybe it would just be reaching us now. but I guess if this were to be the case, it would have to be traveling faster than light...
DaveC426913 said:Except for some local objects, the vast bulk of deep sky objects are receding from us. The farther away they are, the faster they are receding.
Picture a rapidly expanding balloon covered in wandering ants. All ants are receding from us as the balloon expands, but because they all have their own (small) motions, some are receding fast, others slower. A very few right nearby might have local motion towards us even as the balloon is expanding, causing the distance to us to slightly decrease over time.
There are no dumb questions except unasked questions.SolidHelix said:Yeah I understand, while on the topic and I'm not getting bashed for asking stupid questions, since the universe as we accept (i guess generally) that the universe is expanding like a balloon as you said, and we and all objects are the ants, if one object were to exit away from everything else, in a direction where there were no known objects and keep going would it's "presence" expand the universe? or would it have to end up following the curvature of the balloon and end up meeting something other object in our universe? I know long winded and probably hard to understand my meaning.
DaveC426913 said:There are no dumb questions except unasked questions.
The universe is not a bubble that is expanding into a void. There is no void. The universe has no boundary.
This is where the balloon analogy works to make a good point. The universe does behave somewhat like a balloon in that sense. As the balloon expands its surface gets larger in area. But its surface has no boundary. The ants do not see any edge. No ant is closer to any edge than any other ant.
Well said.Simon Bridge said:You are right in that these are very common questions. But they bear repeating - and each time we see the question we have to make slight changes to how we present the answers, which deepens our understanding of the concepts involved. This is why so many people have a lot of patience with this sort of thing.
Chronos said:You might end up back where you started if the universe is closed. Of course you will have no clue you have circumnavigated the universe since it will have evolved and expanded for billions of years while you were out circumnavigating it.
There are several methods used to detect very far away objects, including telescopes, radio telescopes, and space-based observatories. These instruments use different wavelengths of light to capture images and data from distant objects.
The farthest object that has been detected by humans is GN-z11, a galaxy located about 13.4 billion light-years away. However, with advancements in technology, scientists are constantly pushing the limits and detecting objects even farther away.
One of the main challenges in detecting very far away objects is the vast distance and time it takes for light to reach us. This means that the light may have been traveling for billions of years and can be very faint by the time it reaches our instruments. Another challenge is the interference from Earth's atmosphere, which can distort and block the light from these objects.
Scientists use a variety of methods to determine the distance of very far away objects, including parallax measurements, redshift, and standard candles. These methods involve observing the object's motion, its spectral lines, and its brightness, respectively.
By detecting very far away objects, we can learn more about the history and evolution of the universe, as well as gain insights into the formation of galaxies and stars. We can also study the properties of these objects, such as their composition, temperature, and size, which can help us understand the laws of physics and the nature of our universe.