Top Most Astronomy Interview Questions Part – 4

How Many Planets Are In The New Solar System?

At the time of writing the new solar system has not been agreed officially, however it appears that there will be 12 planets in the new solar system, having gone up from 9 previously.

The new additions would be Ceres, Charon and an obscurely named object far away from the sun called 2003 UB319 really needs to have a catchier name assigned to it!

How Many Planets Are Now In The Solar System?

There are now eight planets in the solar system, as Pluto has been demoted to a planetoid along with its moon Charon that has been promoted to that status along with the largest asteroid called Ceres.

How Many Stars Are There In The Whole Universe?

We can at the least say the number is so huge that we cannot comprehend it; given that there are billions of stars in each galaxy and there may be for all we know trillions of galaxies then the number is truly collosal.

It is also of course in a constant state of flux as stars are born and other stars die or collide and change state therefore the number is also ever changing.

How Old Is Our Earth?

Of course, no one knows exactly how old the earth is, however science can give what it believes to be accurate estimates of the age of the earth using various dating techniques.

At present, the generally accepted estimate is that the Earth is between some 4.5 to 4.6 billion years old. This is based partly on radiometric dating techniques and partly on extrapolation back in time and looking at the universe around us.

How Old Is This Universe?

The age of the earth soon put paid to that and recently sophisticated scientific techniques have pointed at a much greater age.

Some have thought the question incoherent or at least that its presupposition should be stated clearly that is, that the universe has a beginning and therefore point where it came into existence.

However, there seems to be strong evidence that the universe has not always existed and therefore this is a coherent question.

We need to say that if the big bang is true, we can go back only to say something like ‘when was the big bang’ as direct access to existence of the universe before then may be something we can never empirically have depending on the definition of the big bang and what may have gone before.

Typical estimates of the age of the universe are around 14 18 billion years, based on globular clusters.

How Was The Moon Formed?

How the moon formed is a good question. Over time, the theories have abounded as to how the moon was formed, and what it consists of.

The current theory that seems to fit the facts the best is that it is actually very old earth rocks. At some stage a huge collision took a massive chunk of rock out of the earth and flung it out into space this rock became the moon.

If a human was to float in space and he look up would there be other planets on top of the planets in out galaxy. He would not be able to see the other planets without a telescope from space either, or at least not in any detail.

If Gravity Only Attracts Mass And If Light Does Not Have Mass Why Does It Appear To Bend When Passing A Planet?
Under general relativity, it is seen that gravity can literally warp spacetime around it.

Therefore, anything that passes through the gravitational warping will itself be influenced.

Around a massive object like the sun, there is a slight warping of spacetime, and therefore everything that passes through that is affected.

This is what causes the slight bending, you notice in light waves even though they cannot have mass in the standard model (as it takes infinite energy to accelerate anything that has mass to light speed)

Is Pluto Really A Planet?

The motivation for this has been the increased understanding of our solar system and the huge number of large rocks that have been found at a greater distance from the Sun than Pluto, which orbits it; in fact some larger than Pluto has or of similar size have been found.

This has led to many calling for our understanding of a true planet to change or for Pluto to become a planetessimal or some other nonplanetary body.

However due to convention over the years and its status it seems set for Pluto to stay, however it is worth noting that there are many similar sized objects probably also orbiting the sun at a much greater distance in the Kuiper belt.

Is The Gravitational Pull On An Object Equalized If The Object Is At The Center Of A Planet, I.e. Surrounded By The Mass Of The Planet, Which Is Creating The Gravity?

The gravitational pull in this instance would be the same from all directions, so the net effect would be no movement.

Of course, you would have to be completely encircled by the massive objects like in the centre of a ring for instance.

Is The Moon Escaping The Earth?

However, it is possible that this will reach a steady state, when the pull of the moon is less on the earth it will slow down or stop the rate at which the earth is slowing down its spin from the friction caused. This in turn will place a greater pull back on the moon and hence it may reach a steady distance from the earth.

Is There Water In Moon Rock?

No! The tests on moon rock that has either reached earth, from meteorites or from rock brought back by astronauts, have brought a new meaning to the word dry!

Any water there was would have escaped long, long ago. This has affected the number of minerals possible on the moon around 100 compared to the thousands on earth where water has enabled much more complexity.

What Are Asteroids Like?

Asteroids have several general features of interest.

Firstly, their formation they all represent material that was not used in the initial formation of the solar system.
For whatever reason chance and position they did not form planets, and therefore were left scattered.
They do not represent much material it is thought that if they were all joined together the mass would only be that of half of our Moon!
Most asteroids are in a ‘belt’ between Mars and Jupiter.
Some asteroids even have their own mini moons for instance Ida and Dactyl.

What Are Gamma Ray Bursts?

Gamma ray bursts are one of the current mysteries that are still to be explained.

If we could see gamma ray wavelengths, we would see the sky glow and much of this is from known sources like pulsars, quasars and so on. However, from time to time we have directly observed sudden pulses of gamma rays for a few seconds at a time.

These pulses pour out massive energy. The mystery is with regard the source of these gamma rays.