Some quasars (quasi-stellar radio source) have the largest red shifts ever observed. If this phenomenon is due to cosmic expansion, what can you say about their distance? What can you say about the age of the quasar at the time the light we now see left the quasar compared to the age of the universe? Explain.
Largest redshift means that the source was traveling faster than any other objects (relative to our velocity now) that any other objects in the universe. That makes them among the oldest.
You cannot compare the quasar age relative to the age of the universe (about 15 billion years) without knowing how large the redshift is.
If a quasar has the largest red shift ever observed, it means that its light has been stretched to longer wavelengths due to the expansion of the universe. Based on this phenomenon and our current understanding of cosmic expansion, we can draw a couple of conclusions about the distance and age of the quasar:
1. Distance: The larger the red shift, the greater the distance between the observer (us) and the quasar. Therefore, a quasar with the largest observed red shift would be located at a significant distance from us.
2. Age: The red shift of a quasar also provides information about the age of the quasar relative to the age of the universe. The red shift is caused by the expansion of space, which stretches the wavelengths of light as it travels towards us. The greater the red shift, the longer the light has taken to reach us, implying that the light left the quasar a long time ago.
Since the age of the universe is estimated to be around 13.8 billion years, and the light from the quasar has taken a long time to reach us, this suggests that the quasar must have been much younger when the light we observe today originally left it. In fact, it is possible that the light from the quasar could have originated from a time when the universe was relatively young.
It's important to note that quasars are incredibly bright and distant objects, so observing their red shift accurately is a challenging task. However, studying the red shifts of quasars is a crucial tool for understanding cosmic expansion and the early stages of the universe.
To understand the relationship between the redshift, distance, and age of quasars in the context of cosmic expansion, we need to first discuss the concept of redshift.
Redshift is a phenomenon observed when light from an object moving away from an observer gets stretched to longer wavelengths, shifting towards the red end of the electromagnetic spectrum. It is caused by the expansion of the universe, where the space between objects is continuously stretching. This stretching causes the wavelength of light to increase, and thus we observe a redshift.
Now, when we observe quasars with the largest redshifts ever observed, it indicates that they are moving away from us at a very high speed due to the expansion of space. The higher the redshift, the greater the speed at which the object is moving away.
Based on the principle of cosmic expansion, the redshift of an object is directly related to its distance from us. This relationship is described by Hubble's Law, which states that the velocity at which an object is receding from us is proportional to its distance. Therefore, quasars with larger redshifts are generally further away from us compared to quasars with smaller redshifts.
Regarding the age of the quasar, it is important to note that quasars are extremely distant and can be observed at vast distances in the universe. Since light takes time to travel from the quasar to our telescopes, we are essentially seeing the quasar as it appeared in the past. The redshift of the quasar indicates the extent to which the universe has expanded since the light left the quasar.
If we consider a quasar with a very large redshift, it implies that the quasar is very far away, and thus the light we observe from it has been traveling for a significant amount of time. Therefore, the age of the quasar at the time the light left it would be much closer to the age of the universe compared to a quasar with a smaller redshift. In other words, quasars with larger redshifts allow us to observe objects at earlier stages of the universe's history.
In summary, the large redshifts observed in some quasars indicate that they are located far away from us due to the cosmic expansion. The age of these quasars at the time their light reached us would be closer to the age of the universe compared to quasars with smaller redshifts.