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babunello [35]
3 years ago
14

What do we mean by the observable universe?

Physics
1 answer:
mote1985 [20]3 years ago
4 0
The observable universe<span> is a spherical region of the </span>Universe, <span>comprising all matter that can be observed from Earth at the present time, because light and other signals from these objects have had time to reach Earth since the beginning of the cosmological expansion.


</span>
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The core of the Sun has a temperature of 1.5 × 107 K, while the surface of the Sun has a temperature of 4870 K (which varies ove
ololo11 [35]

Answer:

The Sun and planets are shown to the same scale. The small terrestrial planets and tiny Pluto are in the box---the Earth is the blue dot near the center of the box (montage created by Nick Strobel using NASA images).

Size

The Sun is by far the biggest thing in the solar system. From its angular size of about 0.5° and its distance of almost 150 million kilometers, its diameter is determined to be 1,392,000 kilometers. This is equal to 109 Earth diameters and almost 10 times the size of the largest planet, Jupiter. All of the planets orbit the Sun because of its enormous gravity. It has about 333,000 times the Earth's mass and is over 1,000 times as massive as Jupiter. It has so much mass that it is able to produce its own light. This feature is what distinguishes stars from planets.

Composition

What is the Sun made of? Spectroscopy shows that hydrogen makes up about 94% of the solar material, helium makes up about 6% of the Sun, and all the other elements make up just 0.13% (with oxygen, carbon, and nitrogen the three most abundant ``metals''---they make up 0.11%). In astronomy, any atom heavier than helium is called a ``metal'' atom. The Sun also has traces of neon, sodium, magnesium, aluminum, silicon, phosphorus, sulfur, potassium, and iron. The percentages quoted here are by the relative number of atoms. If you use the percentage by mass, you find that hydrogen makes up 78.5% of the Sun's mass, helium 19.7%, oxygen 0.86%, carbon 0.4%, iron 0.14%, and the other elements are 0.54%.

Explanation:

4 0
3 years ago
Which feature of electromagnets makes them more useful than permanent
mezya [45]
I think it’s D................
4 0
3 years ago
What is the oxidation number of the element Se
maria [59]

Answer:

The oxidation number of a monatomic (composed of one atom) ion is the same as the charge of the ion. For example, the oxidation numbers of K+, Se2−, and Au3+ are +1, -2, and +3, respectively. The oxidation number of oxygen in most compounds is −2.

Explanation:

6 0
2 years ago
When does total internal reflection occur?
gogolik [260]

Answer:

A

Explanation:

I believe it is A because reflection is usually like a mirror or in water the other ones described are refraction or conversion. Hope this helps! :)

3 0
2 years ago
Describe how radio telescopes function.
FrozenT [24]

A radio telescope is simply a telescope that is designed to receive radio waves from space. In its simplest form it has three components:

1. One or more antennas to collect the incoming radio waves. Most antennas are parabolic dishes that reflect the radio waves to a receiver, in the same way as a curved mirror can focus visible light to a point.

2. A receiver and amplifier to boost the very weak radio signal to a measurable level. These days the amplifiers are extremely sensitive and are normally cooled to very low temperatures to minimise interference due to the noise generated by the movement of the atoms in the metal (called thermal noise).

3. A recorder to keep a record of the signal. Most radio telescopes nowadays record directly to some form of computer memory disk as astronomers use sophisticated software to process and analyse the data.

7 0
3 years ago
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