Question

(a) Explain how a galaxy with z > 1.25 could have been closer at the time...

(a) Explain how a galaxy with z > 1.25 could have been closer at the time it emitted the light that we now see compared with a galaxy with z = 1.25. (b) Explain how a galaxy can be further away at the present time than the distance light can travel in the age of the universe. (c) Explain how a galaxy can be moving away from us faster than the speed of light.

Homework Answers

Answer #1

(a) In a universe which is expanding, at a red shift of z = 1.25 and q0 = 0.5, the angular diameter distance becomes maximum and beyond this distance, the farther objects appear larger and dimmer. Hence, the various galaxies can be compared at various red shifts.

Therefore, for a galaxy at z >1.25, it appears larger and closer.

(b) The expanding of the universe is taking place at a faster speed than the speed of light. Hence, a galaxy might also be further away at the present time than the distance light which can travel in the age of the universe.

(c) The light emitted by the galaxies is moving towards us while the galaxies are moving away from us. Being moving in the opposite direction than that of the direction of the light emitted by the galaxies, these start moving with a speed faster than the speed of light.

Know the answer?
Your Answer:

Post as a guest

Your Name:

What's your source?

Earn Coins

Coins can be redeemed for fabulous gifts.

Not the answer you're looking for?
Ask your own homework help question
Similar Questions
8. a) Let’s say one galaxy is 4 Mpc away from us and another is 16...
8. a) Let’s say one galaxy is 4 Mpc away from us and another is 16 Mpc away. If the nearer one moves 1 Mpc, how far will the more distant galaxy move in the same amount of time? b) How far away will each of the galaxies in part A be after that amount of time has passed? 9. How would a higher value for the Hubble constant affect the calculation of the age of the universe? A lower...
Show all calculations and formulas used. The closest star to earth is 4.253 light years away....
Show all calculations and formulas used. The closest star to earth is 4.253 light years away. How far is that in miles? The fastest space probe ever designed has a speed of about 58,000 km/h. How long would it take it to cross the length of the milky way galaxy? If the parallax angle of a star is 0.000075% then how far away is that star? What is the relative brightness of the Sun as seen from Saturn as compared...
Suppose a blazar at a redshift z = 1.0 is observed to have a brightness fluctuation...
Suppose a blazar at a redshift z = 1.0 is observed to have a brightness fluctuation on a timescale of 5 hours as seen from Earth. (a) At what speed does the blazar seem to be moving away from us? (b)_ Using the idea of time dilation, determine how long this fluctuation lasted as measured by an astronomer in the blazar's host galaxy. (c) What is the maximum size (in AU) of the region from which the blazar emits energy...
1. The width of the Milky Way is approximately how large? a. 12 parsecs b. 100,000...
1. The width of the Milky Way is approximately how large? a. 12 parsecs b. 100,000 light years c. 10,000 light years d. 1 million light years 2. The recession of almost all other galaxies away from the Milky Way was first mathematically described by: a. Theory of Special Relativity b. 2nd Law of Thermodynamics c. Hubble's Law d. Kepler's Third Law 3. Which of the following is NOT an active galaxy type? a. radio b. Seyfert c. quasar d....
3/ which of the following stellar properties is the most fundamental to a star’s main-sequence and...
3/ which of the following stellar properties is the most fundamental to a star’s main-sequence and post-main sequence life? A/ temperature B/ mass C/ luminosity D/ radius 4/ Stars Moppit and Boppit orbit each other as members of a binary star system. Their period of rotation about their combined centre of mass is 10 years. The semi-major axis of Boppit’s orbit around the centre of mass is 15.25 AU. What is the combined mass of Moppit and Boppit? A/ Mmoppit...
You joined the SQU science fiction club which is making an animation video about time travel...
You joined the SQU science fiction club which is making an animation video about time travel to the early solar system when the moon was closer to Earth. Your task is to arrive at an accurate description of the orbital motion of the moon at the early solar system when it was at 0.80 the current distance from Earth. You summarized your task in the following questions that you are addressing in order:Hint: Remember the application of Kepler laws in...
1.A) In abut 5 lines explain how associative methods of forecasting differ from Time series methods...
1.A) In abut 5 lines explain how associative methods of forecasting differ from Time series methods of forecasting. B) Which one would you use to explain how the demand for pork might affect the demand for beef? 2. What all does Hard Rock Cafe's Point of Sale (POS) system capture? At what level is the information aggregated? 3. A) In about 5 lines, discuss the key differences between Time Series method of forecasting and Qualitative Methods of forecasting. B) Name...
Activity 1: Scientific Reports You may have heard the question “If a tree falls in a...
Activity 1: Scientific Reports You may have heard the question “If a tree falls in a forest and no one is around to hear it, does it make a sound?” A similar question can be asked about experiments. “If a researcher performs an experiment and never publishes the result has science been performed?” Many people would say no because science is the accumulation of knowledge. If the results of an experiment are not published, knowledge is not gained. The final...
1. A bat uses very high frequencies so: a. He will kill the insects he's hunting...
1. A bat uses very high frequencies so: a. He will kill the insects he's hunting b. We won't hear them c. The sound waves will be small compared to the insects d. The sound waves will be large compared to the insects e. He can tune in to KMET for the weather report 2. Bees see somewhat into the ultraviolet. This is because: a. They use radar b. They can see in the dark c. They evolved with a...
Instructions: In 1974, Loftus and Palmer conducted a classic study demonstrating how the language used to...
Instructions: In 1974, Loftus and Palmer conducted a classic study demonstrating how the language used to ask a question can influence eyewitness memory. In the study, college students watched a film of an automobile accident and then were asked questions about what they saw. One group was asked, “About how fast were the cars going when they smashed into each other?” Another group was asked the same question except the verb was changed to “hit” instead of “smashed into.” The...