Subtropical waters are typically more saline than equatorial waters because of the bigger temperature and much lower precipitation.
The precipitation manages to lower the salinity on the surface of the water even create ''pools'' with fresh water in the middle of the saline water. In the equatorial region there's rain almost every day, so the salinity is lower, while in the subtropical regions there's seasonal rain and it is in much lower amount, the temperature is higher which makes the water evaporate more and the salt to be more concentrated, thus the higher salinity.
Two questions which arises in my mind about aurora borealis are:
- Why does aurora borealis occur?
- Why does aurora borealis occur in a particular time of the year?
Answers:
- As solar wind approaches the Earth, it meets the Earth's magnetic field. In the ionosphere, the ions of the solar wind collide with atoms of oxygen and nitrogen from the Earth's atmosphere. The energy released during these collisions causes aurora borealis.
- Aurora borealis is active the whole year. Since it needs to be dark in order to see aurora borealis in the sky, late August/September through the very beginning of April is the best time to go to a destination located in the aurora zone for a chance to see them.
Note: These are the questions which arises in my mind only. It may differ from person to person.
Hope you could understand.
If you have any query, feel free to ask.
They are alpha world cities of london and paris so that would be like mexico city or dublin,vienna,seoul,tehran
Answer:
For the countour part: Map c, contour is 50m (the lines increases/decreases with 50 meters each step). Map b, need to see the whole map to decide.
<h2>
Answer: The greater the distance to a galaxy, the greater its redshift</h2>
When we talk about the <u>visible electromagnetic spectrum</u>, we know it starts in violet-blue and ends in red.
Now, in this context the astronomer Edwin Powell Hubble observed several celestial bodies, and when obtaining the spectra of distant galaxies he observed the spectral lines were displaced towards the <u>red</u><u> </u>(red shift), whereas the nearby stars showed a spectrum displaced to the <u>blue</u>.
From there, Hubble deduced that the farther the galaxy is, the more redshifted it is in its spectrum, and noted that all galaxies are <em>"moving away from each other with a speed that increases with distance"</em>, and enunciated the now called<u> Hubble–Lemaître Law</u>.
This means in the past the distance between two galaxies was smaller than at present, being this the proof that <u>the universe is expanding</u> (like a balloon expands when it is filled with air or another gas).
At this poitn it is important to stay clear that <u>the redshift is not produced by the relative movement of the galaxies with each other</u>. This effect is in fact, due to the <u>own expansion of the space</u> among the galaxies.
