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erica [24]
3 years ago
13

Astronomers can now report that active star formation was going on at a time when the universe was only 20% as old as it is toda

y. When astronomers make such a statement, how can they know what was happening inside galaxies way back then
Physics
1 answer:
disa [49]3 years ago
8 0

Answer:

First, as you may know, the light travels at a given velocity.

In vaccum, this velocity is c = 3x10^8 m/s.

And we know that:

distance = velocity*time

Now, if some object (like a star ) is really far away, the light that comes from that star may take years to reach the Earth.

This means that the images that the astronomers see today, actually happened years and years ago (So the night sky is like a picture of the "past" of the universe)

Also, for example, if an astronomer sees some particular thing, he can apply a model (a "simplification" of some phenomena that is used to simplify it an explain it) and with the model, the scientist can infer the information of the given thing some time before it was seen.

You might be interested in
When the Earth is closest to the Sun, it is at:
ahrayia [7]

a). Perihelion . . . the point in Earth's orbit that's closest to the Sun.
                            We pass it every year early in January. 


b). Aphelion . . . the point in Earth's orbit that's farthest from the Sun.
                          We pass it every year early in July. 

c). Proxihelion . . . a made-up, meaningless word

d). Equinox . . . the points on the map of the stars where the Sun
                         appears to be on March 21 and September 21.

5 0
3 years ago
Which process produces the energy radiated by the star when it becomes a main sequence star?
inysia [295]
The process that produces the energy radiated by stars is nuclear fusion in the core.
For a star on the main sequence, it's the fusion of hydrogen nuclei into helium.
8 0
3 years ago
Two airplanes leave an airport at the same time. The velocity of the first airplane is 730 m/h at a heading of 44.3 ◦ . The velo
Goshia [24]

Answer:

So airplane will be 1324.9453 m apart after 2.9 hour

Explanation:

So if we draw the vectors of a 2d graph we see that the difference in angles is  = 83 - 44.3 = 83-44.3=38.7^{\circ}

Distance traveled by first plane = 730×2.9 = 2117 m

And distance traveled by second plane = 590×2.9 = 1711 m

We represent these distances as two sides of the triangle, and the distance between the planes as the side opposing the angle 38.7.

Using the law of cosine, d^2 representing the distance between the planes, we see that:

d^2=2117^2 + 1711^2 -2\times (2117)\times (1711)cos(38.7)=1755480.2482

d = 1324.9453 m

4 0
3 years ago
Which occupies mrs space, 3m cubed or 100ft cubed
Slav-nsk [51]

The question is somewhat ambiguous.

-- It's hard to tell whether it's asking about  '3 cubic meters'
or  (3m)³ which is actually 27 cubic meters.

-- It's hard to tell whether it's asking about    '100 cubic feet'
or  (100 ft)³ which is actually 1 million cubic feet.

I'm going to make an assumption, and then proceed to
answer the question that I have invented.
I'm going to assume that the question is referring to
'three cubic meters'  and  'one hundred cubic feet' .

OK.  We'll obviously need to convert some units here.
I've decided to convert the meters into feet.

For 1 meter, I always use    3.28084 feet.

Then (1 meter)³ = 1 cubic meter = (3.28084 ft)³ = 35.31 cubic feet.

So 3 cubic meters = (3 x 35.31 cubic feet) =  105.9 cubic feet.

That's more volume than  100 cubic feet.

6 0
3 years ago
A diver makes 0.50 revolutions on the way from a 9.6-m-high platform to the water. Assuming zero initial vertical velocity, find
devlian [24]

Answer:

ω = 0.36 rev/s = 2.24 rad/s

Explanation:

First, we will find the time taken by the diver to reach the water. For this we use 2nd equation of motion:

h = Vi t + (1/2)gt²

where,

h = height = 9.6 m

Vi = initial vertical velocity = 0 m/s

t = time taken = ?

g = 9.8 m/s²

Therefore,

9.6 m = (0 m/s)(t) + (1/2)(9.8 m/s²)t²

t = √1.95 s²

t = 1.4 s

Now, the average angular speed of diver will be:

ω = No. of Revolutions/t

ω = 0.5 rev/1.4 s

<u>ω = 0.36 rev/s = 2.24 rad/s</u>

7 0
3 years ago
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