# Ans: Help With Astrophysics: Calculate 1600 Light Years Distance & Luminosity

• faisal
In summary, the conversation discussed converting light years to meters, the use of indirect evidence in astronomy, and calculating energy and weight on the surface of the sun compared to Earth.
faisal
Show that 1600 light years is equal to a distance of 1.5x10exp19 ?
The black Hole was detected because of its effects on its neighbouring star. why do astromers have to rely on indirect evidence for looking at stars?
A star has a a radius of 9x10exp7 calculate its lumanosity
4X3.14X2.025EXP15=2.54X10EXP16
Help would be very welcomed.
thank you

faisal said:
Show that 1600 light years is equal to a distance of 1.5x10exp19 ?
A "light year" is a measure of distance, not time. You calculated the number of seconds in 1600 years, which is not the question. How far does light travel in one year? What's the speed of light?

How far is a light year? 10 trillion kilometers -its a guess-

Last edited:
faisal said:
How far is a light year? 10 trillion kilometers -its a guess-
Why guess? Either look it up or look up the speed of light and calculate how far it travels in a year. Distance = speed X time.

1600x9.5exp12=1.52exp16

faisal said:
it was not a guess my friend ...
You were the one who said "it's a guess".

the speed of light = 299 792 458 m / s

No of meters light travels in a second = 299,792,458 (approximately)
No of seconds in a year = ? (work it out)
Hence no of meters light travels in a year = ? (this is one light year, measured in meters)

Hence 1600 light years = ? meters

if your entire mass were to be converted to pure energy, how long could you proviede a MegaW (10^6 W) of energy to help in solving our energy crisises?

help!

how much more or less would you weigh (same as force) at the surface of the sun than on earth?

## What is astrophysics?

Astrophysics is a branch of science that deals with the study of the physical properties and behavior of celestial objects, such as stars, galaxies, and planets, as well as the universe as a whole.

## How do you calculate distance in astrophysics?

In astrophysics, distance is typically measured in light years, which is the distance that light travels in one year. To calculate distance in light years, you can use the formula: distance = speed of light x time. For example, to calculate the distance of 1600 light years, you would use the formula: 1600 light years = (speed of light) x (number of years).

## What is luminosity in astrophysics?

Luminosity is a measure of the amount of energy emitted by a celestial object, such as a star, per unit of time. It is often expressed in terms of the sun's luminosity, which is equivalent to 3.828 x 10^26 watts.

## What is the significance of calculating distance and luminosity in astrophysics?

Calculating distance and luminosity in astrophysics allows scientists to understand the properties and behavior of celestial objects, as well as the structure and evolution of the universe. It also helps in determining the age, size, and composition of these objects.

## What are some tools and techniques used in astrophysics to calculate distance and luminosity?

Some common tools and techniques used in astrophysics to calculate distance and luminosity include parallax measurements, standard candles (such as Cepheid variables and Type Ia supernovae), and spectroscopy. These methods rely on observing the brightness and spectral characteristics of celestial objects to determine their distance and luminosity.

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