One thing that totally fascinates me, and which has slowly become one of my major areas of interest is astrophysics. The grandiosity of the universe is so hard to comprehend, and its complexity and mysteries, all waiting to be discovered, have lured scientists from the dawn of mankind.

As you have probably read in the news today (for those of you, which will definitely read this blog in the future, here's a link to the Article), scientists have now confirmed the existance of a SuperMassive Black hole at the centre of our galaxy - the Milky Way. The most difficult thing to comprehend is to understand the magnitude of this stellar giant at the centre of our galaxy, and what role it has in the stability of the whole stellar system within.

An artist's impression of the centre of our galaxy.

First of all, let us talk about it's mass and dimensions. The latest studies have indicated that the mass of this object is 4 Million Solar Masses (compared to the previous 3.7 Million estimate), with a diameter of 44 Million kilometers. But what do these figures represent? Here is a quick comparison:

• Sun - 333,000 times mass of Earth
  Sagittarius-A - 1.33 Trillion (1,330,000,000,000) times mass of Earth
• Sun - 110 times diamter of Earth
  Sagittarius-A - 3350 times diameter of Earth
• Sun - 5.58 Million (5,580,000) times volume of Earth
  Sagittarius-A - 158 Billion (158,000,000,000) times volume of Earth
• Sun - 0.0597 times density of earth (16.7 times less dense)
  Sagittarius-A - 8.41 times denser than earth

The density is also impressive. A volume of 10cm x 10cm x10cm (1000cc) was to be filled with each of the following, here are the respective weights:

• Water - 1Kg
• Gold - 19.3Kgs
• Osmium (densest element known to man) - 22.61Kgs
• Earth (average) - 6.88Kgs
• Sun (average) - 0.41Kgs
• Sagittarius A (average) - 58Kgs

The impressive density of the black hole, which is higher than any known element or material makes its action on the galaxy even more apparent, but this will be tackled in another blog entry.

Relative positioning of Earth and Sagittarius-A in the Milky Way

A recent study has revealed that the Milky Way, the galaxy which we form part of is actually larger, bulkier and spinning a lot faster than what astronomers previously thought. For decades, the Milky Way was considered to be the smaller sister of our neighbouring galaxy Andromeda, but this scenario has changed. By mapping the Milky Way in a more detailed, three-dimensional way, it was found that the galaxy is in fact 15% larger in breadth. More important, it is denser, with 50% more mass, making the galaxy now look like the fraternal twin of Andromeda, rather than its smaller sibling. The Milky way is also spinning faster at its centre, now the figure adjusted to 568,000mph (compared to the previous calculation of 492,000mph). What this means that the doomed collision between the Milky Way and Andromeda will happen even earlier than predicted. But don't worry, we're looking at about 2-3 Billion Years from now. So, no need to panic. I'm pretty sure that nobody reading this article will be there to live the experience.

You can download a high-resolution photo (2700x2700 pixels) from the images section of the site.