# When you look at a distant galaxy through a telescope, how is it that you're looking backward in time?

928 results
1. ## astronomy

In space, the angular resolution of the Keck telescope is govererned by the diffraction limit. How far away could you read the same book, using the Keck telescope in space? Please express your answers in units of meters.

2. ## astronomy

The Keck telescope on Mauna Kea has an angular resolution on Earth of half an arcsecond. How far away (in meters) could you read ("resolve the letters of") a book with 3 mm square type, using the Keck telescope on Earth?

3. ## Trigonometry application

I need help with this problem. am having trouble solving this. A rocket tracking station has two telescopes A and B placed 1.7 miles apart. The telescopes lock onto a rocket and transmit their angles of elevation to a computer after a rocket launch. What

4. ## English

Read the passage from “Burçin’s Galaxy.” Just a few years ago, while earning her Ph.D. at the University of Minnesota, Mutlu-Pakdil and her colleagues discovered PGC 1000174, a galaxy with qualities so rare they’ve never been observed anywhere

5. ## Astronomy

You see a galaxy which lies at distance D from the earth. You measure a flux from this galaxy of f. If you assume a mass-to-light ratio of r (i.e. r is the number of kilograms needed to generate one watt of radiation), derive an equation for the stellar

6. ## History

Which identifies an important discovery made during the Renaissance with the use of the newly invented telescope? A. The earth previously had multiple moons B. The edges of our galaxy were mapped out. C. Pluto is the last planet in our solar system. D. The

7. ## Algebra

A light year, the distance light travels in 1 year, is approximately 5.9×10^12 miles.A nearby galaxy is approximately 1.2×10^7 light years from our galaxy. Find the distance in miles between our galaxy and the nearby galaxy. IDK this question. I first

8. ## physics

The sun rotates around the center of the milky way galaxy at a distance of about 30,000 light years (1ly= 9.5*10^15m). if it takes about 200 million years to make one rotation, estimate the mass of our galaxy. Assume that the mass distribution of galaxy is

9. ## Math

The Hale Telescope has a mirror of diameter 5.1 meters and a focal length of 16.9 meters. The Keck 1 Telescope has a mirror of diameter 10 meters and a focal length of 17.5 meters. Which telescope has a greater light-gathering power (i.e., can collect more

10. ## Physics

On a distant planet, golf is just as popular as it is on earth. A golfer tees off and drives the ball 4.1 times as far as he would have on earth, given the same initial velocities on both planets. The ball is launched at a speed of 50 m/s at an angle of

11. ## astronomy

Imagine that you live in a distant galaxy far far away. This galaxy is in a different universe, and so may have different cosmology. It seems that in this distant universe, all galaxies have the same luminosity, which you have worked out is 7.0*10^30 W.

12. ## Physics

A telescope with a small circular aperture of diameter 2.0 centimeters. If two point sources of light are being imaged by this telescope, what is the maximum wavelength at which the two can be resolved if their angular separation is radians?

13. ## Physics

The diameter of our disk-shaped galaxy, the Milky Way, is about 1.7E+5 light-years (ly). The distance to the Andromeda galaxy, which is the spiral galaxy nearest to the Milky Way, is about 1.9E+6 ly. If a scale model represents the Milky Way and Andromeda

14. ## PHYSICS

An astronomical telescope has an objective lens of 80cm and an eyepiece of 5cm focal length.If the final image is formed 25cm from the eye piece when a distant object is viewed by the eye close to the eyepiece,determine the magnifying power of the

15. ## Astronomy - help!

Imagine that you have obtained spectra for several galaxies and have measured the observed wavelength of the H emission line of atomic hydrogen. The rest wavelength of H is 656.3 nanometers (nm). Your results are as follows: • Galaxy 1: Observed H

16. ## ASTRONOMY

In which type of galaxy would you most likely to observe a massive star supernova – in a giant elliptical or in a large spiral galaxy? Explain

17. ## Physics

The space shuttle releases a space telescope into orbit around the earth. The telescope is traveling at a speed of 1700m/s in 25 seconds. What is the distance of the satellite? d = v x t d = 1700 x 25 = Is that the correct formula? Thank you.

18. ## Science need help ?????///

An astronomer observes two galaxies, A and B, which have redshifts of: Galaxy A = 0.020 and Galaxy B = 0.010. Which galaxy is closest to us and what is its distance away from us? You may assume that the Hubble constant is H0 = 75 km s–1 Mpc−1 and that

19. ## Physics

The Hubble Space Telescope (HST) has recorded evidence of a black hole at the center of the M87 galaxy. Using Doppler data, it's been measured that matter is orbiting the center of this galaxy at an orbital speed of 7.5x10 5 m/s, out at a radius of 5.7x10

20. ## physics

An astronomical telescope has an object lens of 80cm and an eyepiece of 5cm focal length.If the image is formed 25cm from the eye piece when a distant object is viewed by the eye close to the eye piece ,detemine the magnifying power of the telescope.What

22. ## to ms.sue-writing prpject

plzzz check: for my birthday, i asked for an MP3 player, but instead, my parents got me a telescope. the telescope was old and rusty, so I put it aside. when i finished dinner, I took the telescope with me to my room. i dusted and cleaned the telescope so

23. ## PHYSICS--

The objective and eyepiece of an astronomical telescope are double convex lenses with refractive index 1.5. When the telescope is adjusted to infinity, the separation between the two lenses is 16 cm. If the space between the lenses is now filled with water

24. ## Math (Physics)

A galaxy is moving away from Earth. The "blue" hydrogen line at 434 nm emitted from the galaxy is measured on Earth to be 458 nm . Part A How fast is the galaxy moving? Answer--> v=____ c Part B How far is it from Earth based on Hubble's law? Answer-->

25. ## Physics!

The sun goes around the center of our galaxy once every 250 million years. The sun is also 2.55×10^20 m from the center of our galaxy. What is the acceleration of our sun towards the center of the galaxy in m/s^2?

26. ## calculus 2

An object thrown in the air on a planet in a distant galaxy is at height s(t) = -20t^2 +67t +42 feet at time t seconds after it is thrown. a) From what height was the object thrown? b) With what velocity was the object thrown? c) What is the acceleration

27. ## Math

As the earth revolves around the sun, distant objects can be seen from different locations. This idea can be used to measure the distance between earth and nearby stars and is called stellar parallax. To see how this process works, consider the simplified

28. ## physics

Radio waves of wavelength 163 m from a galaxy reach a radio telescope by two separate paths as shown in the figure below. One is a direct path to the receiver, which is situated on the edge of a tall cliff by the ocean, and the second is by reflection off

29. ## physics

Radio waves of wavelength 163 m from a galaxy reach a radio telescope by two separate paths as shown in the figure below. One is a direct path to the receiver, which is situated on the edge of a tall cliff by the ocean, and the second is by reflection off

30. ## physics

A reflecting telescope is used to observe two distant point sources that are 3.50 m apart with light of wavelength 600 nm. The telescope's mirror has a radius of 5.0 cm . What is the maximum distance in meters at which the two sources may be distinguished?

31. ## physics

A telescope that has a 100 cm focal length objective and a 3.00 cm focal length eyepiece. Find the distance between the objective and eyepiece lenses in the telescope needed to produce a final image very far from the observer, where vision is most relaxed.

32. ## cosmology

A galaxy with an apparent magnitude in the V band (λc ~ 5550 angstroms, width δλ ~ 800 angstroms) of mV = 22.5 mag is observed with the Palomar 200-inch telescope. How many photons per second are collected from this galaxy over the 200-inch (~ 500 cm)

use each word or phrase as the subject of a sentence. add a verb describing an action that place in the present. make sure each verb agrees with its subect. they give a word my son make a sentence i just want to now did he write correct sentence or no the

34. ## physics

Two stars are 2.4 × 1011 m apart and are equally distant from the earth. A telescope has an objective lens with a diameter of 1.72 m and just detects these stars as separate objects. Assume that light of wavelength 590 nm is being observed. Also, assume

35. ## physics

Two stars are 4.40 1011 m apart and are equally distant from the earth. A telescope has an objective lens with a diameter of 1.03 m and just detects these stars as separate objects. Assume that light of wavelength 550 nm is being observed. Also assume that

36. ## physics

Two stars are 3.80 1011 m apart and are equally distant from the earth. A telescope has an objective lens with a diameter of 1.19 m and just detects these stars as separate objects. Assume that light of wavelength 550 nm is being observed. Also assume that

37. ## to ms.sue-writing project part 1

Narrative Prompts (choose only one) • Your aunt arrives with a huge box. You hear strange noises coming from the box. Write a story about what’s inside. • Although you asked for an MP3 player for you birthday, your parents gave you a telescope. But

A hydrogen atom, when vigorously perturbed, can emit light with a frequency of 6.16·1014 Hz. When the same light from hydrogen atoms in a distant galaxy is observed on earth, the frequency is 5.76·1014 Hz. Calculate the speed at which the galaxy is

39. ## Physics - mass of a galaxy

A star at the edge of the Andromeda galaxy appears to be orbiting the center of that galaxy at the speed of about 200km/s. The star is about g*10^9AU from the center of the galaxy. Calculate a rough estimate of the mass of the Andromeda galaxy. Earth

40. ## science

which of the statements below is true? a) the stars in a galaxy are held together by gravity b) Stars in a galaxy slowly rotate around a center c) The Milky Way is the only galaxy in the universe d)All of the above just need to know if my answer is correct

41. ## Astronomy/History

I am doing a project on Isaac Newton. Ive looked at his impact on the development of the telescope, in particular, the reflecting telescope. Ive researed this a bit and have found conflicting dates. Some sources say he built the first relflecting telescope

42. ## Physics

the hubble telescope has a mass of 1.5 x 10^4 kg and its orbiting the earth 596 km above the ground surface.the earths radius is 6.38 x 10^3km. CAlculate a)the force of gravitation on the telescope due to the earth's pull. given: G=6.67 x 10^-11Nm/kg and

43. ## Cosmology

What observations were used by Edwin Hubble to show that the universe is expanding? - The distance to a galaxy is proportional to its luminosity. - The distance to a galaxy is inversely proportional to its apparent size. - The distance to a galaxy is

44. ## science

100,000 light years refers to... • the size of the spirals with or galaxy (Milky Way) • an approximate measure of the luminosity of the galaxy • an approximate measure of the distance across the galaxy****

45. ## Physics

A star of mass 2.0 1028 kg that is 1.6 1020 m from the center of a galaxy revolves around that center once every 3.4 108 years. Assuming that this star is essentially at the edge of the galaxy, each of the stars in the galaxy has a mass equal to that of

46. ## Physics Help Please --- Telescope

An astronomical refracting telescope is made from two lenses. the objective lens has a focal length of 114 cm, and the eyepiece lens has a focal length of 17 cm. a) What is the total length of the telescope? b) What is the angular magnification of the

47. ## physics

A star of mass 2.0 1031 kg that is 4.8 1020 m from the center of a galaxy revolves around that center once every 4.2 108 years. Assuming that this star is essentially at the edge of the galaxy, each of the stars in the galaxy has a mass equal to that of

48. ## earth

A distant galaxy is simultaneously rotating and receding from the earth. As the drawing shows, the galactic center is receding from the earth at a relative speed of uG = 1.7 x 106 m/s

49. ## maths

the galaxy we live in is roughly lens shaped,and pins.its diameter is given inlight years. (1 light year=9.5Exp12km) calculate the circuference or our galaxy in kilometres. the earth is at a point 3Exp4 light yaersfrom the centre.How far does the earth

50. ## Physics

The sun goes around the center of our galaxy once every 250 million years. The sun is also 2.55×10^20 m from the center of our galaxy. What is the acceleration of our sun towards the center of the galaxy in m/s^2? Details and assumptions You may assume

51. ## Physics

Determine the resolving power of a telescope,if the objective of a telescope has a diameter of 300mm.The mean wavelength of the light from Stars is 6*10^-7m.

52. ## Algebra

The Hubble Space Telescope can see stars and galaxies where brightness is 1/50 of the faintest objects now observable using ground-based telescopes. Use the fact that the brightness of a point source, such as a star, varies inversely as the square of its

53. ## Astronomy

The apparent brightness of a Cepheid variable star in a far-away galaxy is measured to be 640,000 times fainter compared to an equivalent star 2,000 light years away from the Sun in our Galaxy. Assuming that there is no light absorption between galaxies,

54. ## science help PLS

The light from one end of the Milky Way galaxy takes about 150,000 years to travel to the other end. Which of these statements is correct about the Milky Way galaxy? A: The distance between the two ends of the galaxy is 150,000 light years. B: It would

55. ## science

The sun goes around the center of our galaxy once every 250 million years. The sun is also 2.55×1020 m from the center of our galaxy. What is the acceleration of our sun towards the center of the galaxy in m/s2?

56. ## Astronomy

Given that the mass of the Milky Way galaxy is 10^11 times that of the Sun and that the sun is 2.6x10^20 meters from its center, what is the Sun's orbital speed around the center of the galaxy? How long does it take the Sun to orbit the Milky Way? (In this

57. ## Physical Science

Galaxy A is 600 million light years from earth. Galaxy B is moving away from the earth at a speed that is 80% as large as that of Galaxy A. How far from earth is Galaxy B? A. 750 million light years. B. 640 million light years. C. 540 million light years.

58. ## simple PHYSICS!!!

The sun goes around the center of our galaxy once every 250 million years. The sun is also 2.55×10^20 m from the center of our galaxy. What is the acceleration of our sun towards the center of the galaxy in m/s^2?

59. ## physics

The sun goes around the center of our galaxy once every 250 million years. The sun is also 2.55×10^20 m from the center of our galaxy. What is the acceleration of our sun towards the center of the galaxy in m/s^2?

60. ## Physics help ASAP

Suppose you are visiting a planet in a distant part of the galaxy.To determine the acceleration due to gravity on this planet, you drop a rock from a height of 55 m. The rock strikes the ground 1.9 s later.How many times greater is the acceleration due to

61. ## physics

A particular spiral galaxy can be approximated by a thin disk-like volume 35 Thousand Light Years in radius and 8 Hundred Light Years thick. If this Galaxy contains 790 Billion stars, estimate the average distance between the stars in this galaxy. Hint:

62. ## physics

A particular spiral galaxy can be approximated by a thin disk-like volume 35 Thousand Light Years in radius and 8 Hundred Light Years thick. If this Galaxy contains 790 Billion stars, estimate the average distance between the stars in this galaxy. Hint:

63. ## physics

The Yerkes refracting telescope has a 1 m diameter objective lens of focal length 20 m.Assume it is used with an eyepiece of focal length 4.31 cm. Find the angular magniﬁcation of the planet Mars as seen through this telescope

64. ## astronomy

The Keck telescope on Mauna Kea has an angular resolution on Earth of half an arcsecond. How far away (in meters) could you read ("resolve the letters of") a book with 3 mm square type, using the Keck telescope on Earth?

65. ## Trigonometry

I am having trouble solving this. A rocket tracking station has two telescopes A and B placed 1.7 miles apart. The telescopes lock onto a rocket and transmit their angles of elevation to a computer after a rocket launch. What is the distance to the rocket

66. ## Physics: Focal length why is my answer wrong?

An old refracting telescope in a museum is 44.0 cm long and the caption states that the telescope magnifies images by a factor of 29.0. Assuming these numbers are for viewing an object an infinite distance away with minimum eyestrain, what is the focal

67. ## physics

On a distant planet, golf is just as popular as it is on earth. A golfer tees off and drives the ball 4.9 times as far as he would have on earth, given the same velocities on both planets. The ball is launched at a speed of 54 m/s at an angle of 42° above

68. ## geometry

The Hubble Space Telescope is orbiting Earth 600 km above Earth's surface. Earth's radius is about 6370 km. Use the Pythagorean Theorem to find he distance a from the telescope to Earth's horizon. Round your answer to the nearest ten kilometers.

69. ## physcs

Two newly discovered planets follow circular orbits around a star in a distant part of the galaxy. The orbital speeds of the planets are determined to be 41.8 km/s and 64.6 km/s. The slower planet's orbital period is 8.84 years. (a) What is the mass of the

70. ## College Physics

Two newly discovered planets follow circular orbits around a star in a distant part of the galaxy. The orbital speeds of the planets are determined to be 43.5 km/s and 54.0 km/s. The slower planet's orbital period is 6.53 years. (a) What is the mass of the

71. ## Physics

Two newly discovered planets follow circular orbits around a star in a distant part of the galaxy. The orbital speeds of the planets are determined to be 36.0 km/s and 50.6 km/s. The slower planet's orbital period is 7.78 years. (a) What is the mass of the

72. ## college physics 1

Two newly discovered planets follow circular orbits around a star in a distant part of the galaxy. The orbital speeds of the planets are determined to be 35.1 km/s and 63.3 km/s. The slower planet's orbital period is 6.74 years. (a) What is the mass of the

73. ## physics 1

Two newly discovered planets follow circular orbits around a star in a distant part of the galaxy. The orbital speeds of the planets are determined to be 43.6 km/s and 63.5 km/s. The slower planet's orbital period is 8.36 years. (a) What is the mass of the

74. ## physics

astronomical observations of our milky way galaxy indicate that it has a mass about 8.0 *10^13 times the mass of our sun. a star orbiting on the galaxy edge is about 6.0*10^4 light years a way from the galactic center what is the orbital period of that

75. ## Cosmology

magine you look through a really strong telescope and see a rich cluster. Your telescope is so good that you can see a single galaxy at the center of the cluster. What can you say about that galaxy and be pretty confident that you are correct? It has mass

76. ## Physics

When you look at a distant galaxy through a telescope, how is it that you're looking backward in time?

77. ## unsolved mysteries astrophysics

Q3.2 COLLAPSE TIMESCALE (5 points possible) Imagine that you live in a distant galaxy far far away. This galaxy is in a different universe, and so may have different cosmology. It seems that in this distant universe, all galaxies have the same luminosity,

78. ## physics

Galileo's first telescope used a convex objective lens with a focal length f = 1.65 m and a concave eyepiece. When this telescope is focused on an infinitely distant object, and produces an infinitely distant image, its angular magnification is +3.11. What

79. ## Physics

Please help me solve this! The spectrum of the sodium atom is detected in the light from a distant galaxy. If the 590.0 nm line is redshifted to 658.5 nm, at what speed is the galaxy receding from the Earth?

80. ## Science

I need to now in order which of these are big in order from biggest to smallest: Moon, Whirlpool Galaxy, Hubble Deep Feild Galaxies, Hubble Space Telescope, Pleiades Star, Cluster, Saturn Sun Then the distance from closest earth to the farthest in order:

81. ## Science

Reflecting telescopes are popular because they're A. more durable than a refracting telescope. B. easier to build than a refracting telescope. C. smaller than a refracting telescope. D. more powerful than a refracting telescope i said b but im torn between

82. ## Astronomy

A galaxy is receding away from us with a recession velocity of 100,000 km/s. What is the distance to this galaxy? What is the redshift z of this galaxy?

83. ## Doppler Effect

How fast must we be approaching a distant galaxy emitting yellow light (590nm) for it to appear green (520nm)? I believe it uses doppler effect, but how?

84. ## physics

A hydrogen atom, when vigorously perturbed, can emit light with a frequency of 6.16 × 1014 Hz. When the same light from hydrogen atoms in a distant galaxy is observed on earth, the frequency is 5.21 × 1014 Hz. Calculate the speed at which the galaxy is

85. ## Physics

Our Milky Way galaxy is very similar to our neighboring galaxy Andromeda. Consider that each galaxy contains approximately 4.0 x 10^11 stars each star having an average mass of 2.0 x 10^30 kg. a. If the gravitational pull of Andromeda is 2.4 x 10^30 N, how

86. ## Physics

The wavelength of light emitted from a distant galaxy by a hydrogen atom is observed to be 400 nm. If it is known that the laboratory wavelength of this light emitted by hydrogen is 380 nm, what is the velocity of the galaxy? (a) .135c away from Earth (b)

87. ## science

The brightest galaxy in the Bootes cluster of galaxies is found to have a redshift of 0.13. (Assume the speed of light, c, is 3.0 × 10 8 m s−1.) (i) Assuming the Hubble constant, H0, is 70 km s−1 Mpc−1 to two significant figures, calculate the

88. ## physics-lenses

a certain Galilean telescope has a magnification of 2 times. if the focal length of the objective lens is 60 cm, how long is the telescope? thanks :))

89. ## astronomy

whereas a reflecting telescope uses to gather light refracting telescope uses

90. ## science

how is the suns galaxy a spiral galaxy and how does the milky way look I can't find any pictures

91. ## Astronomy

Supernovae can eject material at velocities of 0.001c. Will gas ejected by a supernova which occurs inside a dwarf galaxy with a mass of 10^8 Msolar and a radius of a few kpc be able to escape the galaxy? Yes or No

92. ## Science

The space shuttle releases a space telescope into orbit around the earth.the telescope goes from being stationary to traveling at a speed of 1700 m/s in 25seconds.what is the acceleration of the satellite?

93. ## physics

The Hubble Space Telescope orbits Earth 621 km above Earth's surface. What is the period of the telescope's orbit? Give answer with 5 significant figures.

94. ## Covenant polytechnic. Aba.

Two converging lenses having power of +2.0 and +20.0 diopter are used to give magnifications in an astronomical telescope. calculate the angular magnification of the telescope when (I).in normal adjustment. (ii).The final image is formed at the least

95. ## Astrobiology

What is the Wow! signal? A) A UV signal, recorded by the International Ultraviolet Explorer in 1975 B) A strong narrow-band radio signal, detected by the Big Ear radio telescope in 1977 C) A ultraviolet light beam, captured by the Hubble Space Telescope in

96. ## cosmology

We observe a galaxy at z = 1, and a quasar at z = 2. What is the redshift of the quasar as observed from that galaxy? Enter a numeric answer.

97. ## Physics

Two telescopes A and B spot a star. Telescope A reports the position of the star to be in the East 60 degrees above the horizontal line joining A and B. Telescope B, which is 500 km West of telescope A spots the star at 30 degrees above the horizontal line