Navigation in Space

Chào! In Science today I will be answering some questions about navigation in space and also, just space in general. Leave me some feedback! If you got the chance, would you ever visit  space? 🪐

1. What is a solar system? The Solar System is the gravitationally bound system of the Sun and the objects that orbit it, either directly or indirectly. Of the objects that orbit the Sun directly, the largest are the eight planets, with the remainder being smaller objects, the dwarf planets and small Solar System bodies.

2. What is a star? Describe a Nebula A nebula is a giant cloud of dust and gas in space. Some nebulae (more than one nebula) come from the gas and dust thrown out by the explosion of a dying star, such as a supernova. Other nebulae are regions where new stars are beginning to form.

3. How do stars die? Most stars take millions of years to die. When a star like the Sun has burned all of its hydrogen fuel, it expands to become a red giant. This may be millions of kilometres across - big enough to swallow the planets, Mercury and Venus.

After puffing off its outer layers, the star collapses to form a very dense white dwarf. One teaspoon of material from a white dwarf would weigh up to 100 tonnes. Over billions of years, the white dwarf cools and becomes invisible.

Stars heavier than eight times the mass of the Sun end their lives very suddenly. When they run out of fuel, they swell into red supergiants. They try to keep alive by burning different fuels, but this only works for a few million years. Then they blow themselves apart in a huge supernova explosion.

4. Is there an up or down in space? There is an up and down in space. "Down" is simply the direction gravity is pulling you, and "up" is just the opposite direction. Since there is gravity everywhere in space, there is also an up and down everywhere in space. Gravity is a centrally attractive force, so "going down" means falling or being pulled towards the center of the nearest massive object. If you are in space and the earth is the nearest astronomical object, you fall towards the earth. Down is therefore towards the earth's center and up is away from the earth's center when close to the earth.

5. How can stars be used to navigate? By learning where the stars are in the night sky with your palm facing towards the sky you can figure out where you're going. Some primitive tribes accomplished amazing feats of pathfinding using only the sky as their guide. The Māori came to New Zealand from eastern Polynesia, probably in several waves between the years 1280 to 1300. With no instruments or tables to consult, they very carefully observed the night sky as well as local weather patterns and ocean currents. 

Bonus Questions

1. What does the word spaghettification mean? Spaghettification means theoretical stretching of an object as it encounters extreme differences in gravitational forces, especially those associated with a black hole.

2. Find 3 facts about a black hole 

1. You Can’t Directly See a Black Hole

A black hole is called a black hole because of its colour, especially since light can’t escape. What we can see, though, is the effects of a black hole. Analyzing the surrounding area of a black hole, we can see its effects upon its environment. For example, a star that’s close enough to a black hole can be seen being ripped apart.

2. Our Milky Way Probably Has a Black Hole

But, don’t be alarmed, Earth isn’t in danger! The major black hole that astronomists believe to be within our Milky Way is light years away from Earth.

3. Dying Stars Lead to Stellar Black Holes

The death of large stars leads to black holes because a star’s gravity will overwhelm the star’s natural pressure that it maintains to keep its shape. When the pressure from the nuclear reactions collapses, gravity overwhelms and collapses the star’s core, and the star’s other layers are thrown off into space, and this process is also known as a supernova. The remainder of the core collapses, a spot overcome by density and without volume – a black hole.