1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Gelneren [198K]
3 years ago
13

What object is thousands of kilometers?

Biology
1 answer:
uranmaximum [27]3 years ago
4 0

If we talk about "space" as being anything in the universe outside the atmosphere of Earth, then space is very, very big indeed.  How big?  The diameter of the Earth is 12 000 kilometers.  The distance from the Earth to the moon is 400 000 kilometers.  The diatance from the Earth to the sun is 150 million kilometers.  The diameter of the entire solar system, as measured by the orbit of Neptune, is about 8000 million kilometers.  The distance from here to the nearest star (other than our own sun) is 40 million million kilometers.  The distance from here to the center of our galaxy is about 250 000 million million kilometers.  The distance to the great nebula in Andromeda, the nearest galaxy believed to be similar to our own, is 15 million million million kilometers.  And the distance to the edge of the known universe is around 100 000 million million million kilometers.

To allow astronomers to use reasonably small numbers in conversation when they're talking about the distances between planets, they use a distance called the Astronomical Unit.  One Astronomical Unit, or A.U., is just the average distance between the Earth and the sun, which works out to 149 597 870 kilometers.  A beam of light would take 8-and-1/3 minutes to cross this distance, which, to put it another way, means that anything we see happening on the surface of the sun actually took place 8 minutes and 20 seconds ago.  In terms of this unit, Pluto's orbit is only 40 A.U.s from the sun, and Mercury orbits the sun a scant 0.4 A.U.s away from it.  However, the nearest star is still 260 000 A.U.s from us, which means that such a large unit is still too small to use to talk about the distances to nearby stars.

Distances to nearby stars are measured by using trigonometric parallax.  Put simply, if you measure where in the sky a star is in December, and then measure its position again in June, it will have shifted a tiny tiny bit in relation to distant background stars.  This is similar to the way the position of a nearby object seems to shift in relation to the background if you look at it with your left eye, then with your right.  This tiny movement is called the parallax angle.  Even for the closest stars, the parallax angle measures less than one arc-second (1/3600 of one degree), which is about the diameter of the small white disk that the star makes on a photographic plate if you take a picture of it with a really big telescope.  The distance a star would have to be away to have a parallax angle of only one arc-second is called a parsec, and works out to a whopping 206 265 A.U.s; a star whose parallax angle was 1/2 an arc-second would be two parsecs away.  Such small angles can be measured if done carefully, and have been measured for most of the stars believed to be nearby.  Compared with the planets of our own solar system, the stars are extremely distant and extremely far apart.

The stars are so far apart, in fact, that astronomers and science fiction authors alike prefer to talk about interstellar distances in terms of "light-years."  A light-year is the distance that a beam of light, uninterrupted and in empty space, would travel in a year -- which is about 9 470 000 000 000 (nine million million, four hundred seventy thousand million) kilometers.  A star with a parallax angle of one arc-second works out to be 3.262 light-years away.  In terms of this unit, the nearest star (Proxima Centauri) is only 4.22 light-years away, which is a reasonably low and palatable number.

To put it another way, though, this means that anything we see happening on or near Proxima Centauri actually happened 4.22 years ago.  When we look out at Proxima Centauri through a telescope, we are looking 4.22 years into the past.  When we look at the center of our own galaxy, we're looking 25 000 years into the past.  When we look at the nearest spiral-type galaxy to our own, we're looking one-and-a-half million years into the past.  Thus, when we say the edge of the visible universe is about 10 000 million light-years away, we are also, in a way, saying that the universe is at least 10 000 million years old.

To sum it up, then:

1 A.U. = 149 597 870.61 kilometers

1 light-year = 63 239.7 A.U.s = 9 460 530 000 000 kilometers

1 parsec = 3.261633 light-years = 206 264.806 A.U.s = 30 856 780 000 000 kilometers

You might be interested in
3. Select the dependent variable for answering the stated research question.
In-s [12.5K]

DONT WORRY

ANSWER KO YAN NG MADALI

PERO BRAINLIEST MUNA

MUAAAAAH

TENCHUUUU

4 0
2 years ago
Help me fast its a test and its time<br> true or false All ions are housed in the nucleus of a cell.
malfutka [58]
I’m pretty sure it’s true but not sure
5 0
2 years ago
Read 2 more answers
If tail length in cats is an incomplete dominant trait,what would the resulting offspring of a cross between a long tailed cat (
saw5 [17]
A short cat could be 1 inch. A long tail depending on the cat could be twice as long as body length . what type of cat is it.
5 0
3 years ago
In defining a disease to be studied, epidemiologists use the term disease broadly, but ___________ is a more accurate but cumber
aleksandrvk [35]

Answer: Health outcomes

Explanation:

Health outcome can be defined as the events that occurs after an intervention or care, these events can be measured clinically by physical examination, laboratory testing and imaging; self reported or observed.

Health outcomes are defined as changes in health of an individual or a group of individuals that result from specific healthcare interventions. Example of health outcome is improvement in a patient's eye sight after a cataract surgery.

7 0
3 years ago
Question why won't answers open up where is the log in page
Gwar [14]

Answer:

Hmm I'm not sure I joined only a few days ago.

Explanation:

8 0
2 years ago
Other questions:
  • Which structure carries instructions for producing the proteins that help make a person’s hair curly?
    11·2 answers
  • The bio polymer that has the information directly encoded from the genome is?
    6·1 answer
  • Tests reveal that a client has phosphatic renal calculi. the nurse teaches the client that the diet may include which food item?
    12·1 answer
  • The river source supports little life outside of invertebrates. For each of the organisms listed below. Give one adaption that h
    8·1 answer
  • How much does a 200kg car weigh
    7·2 answers
  • ____________________________ is the process in which humans chose the desired traits of an organism.
    13·1 answer
  • Which one of the following is produced in the greatest numbers during one turn of the Krebs cycle?
    8·1 answer
  • How many different gametes can be produced by a tall, yellow-seeded,
    5·1 answer
  • Why couldn't yeast use both sugar and artificial sweetener for cell respiration?
    11·1 answer
  • For a science experiment, a student rubs a mineral against a porcelain plate. The students has just performed......?
    5·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!