Posts tagged “astronomy

The planet formerly known as…

The cosmos is a place of mystery and wonder – never static, forever changing and challenging our perceptions of what it is.

Look at this picture… does it look any different to you? Because it does to me!

Let me give you a clue…

Did you ever recite this when you were growing up?

“My very elegant mother just served us nine pizzas.”

You did? Then you know that this was a way of remembering the nine planets in our solar system.

HANG ON! Nine? Well, when I was growing up, there were nine planets! But things change – and from 2006 – there are officially only eight planets. So, if you look at the picture again, you’ll see that one of those planets is missing: the cold, mysterious one.

The planet formerly known as Pluto.

If you remember, this caused quite an outcry. It turned out that people were emotionally attached to that little ex-planet. Normally mild astronomers turned into wild beasts as they fought for the planet to retain its status as … well, a true planet.

Indeed, such was the outrage that the American Dialect Society chose ‘plutoed’ as the 2006 Word of the Year. The definition of ‘to pluto’ says it all: to demote or devalue someone or something.

Pluto: Discovered in 1930, Plutoed in 2006.

No one likes change – yet without it, there would be no progress. What we once took for granted as a truth can be overturned. And that is a good lesson for us to remember: there are no absolute truths; just many different perspectives of the truth.

The cosmos is dynamic and in constant motion. We have to unlearn what we once learnt. Pluto has now been re-classified as a dwarf planet and is one of the Kuiper Belt objects.

It is not a demotion, but a change of identity for Pluto. It may no longer be the planet furthest away from the sun, but it is now a pioneer; one of the first citizens on the distant but teeming shore of the unknown.


MACHOs and WIMPs

I can get worried about the small things in life. But obsessed by the big things. Like the universe.

How big is the universe? Does it have a beginning and an end? And what is it made of?

Well, it seems that most of the universe is made up of stuff that we cannot see at all – that is, dark matter.

Dark matter is the name given to mysterious and invisible particles that we assume must exist because of how it interacts with ‘normal’ matter via gravity.

No one seems to know what dark matter is. It could be ordinary matter, strong man matter – like MACHOs (or Massive Compact Halo Objects). Brown dwarfs (not a very macho-sounding name – is it?) and black holes (far more butch!) are examples of MACHOs.

That’s just one possibility! Dark matter could be something else completely: it could be extraordinary matter, which may or may not, be composed of WIMPs (or Weakly Interacting Massive Particles). Neutrinos are WIMPs and quite possibly photinos and neutralinos (although they do not like being called this).

The best guess is that dark matter is made up of both ordinary and extraordinary matter.

What I find so mind-boggling is that only 10%-30% of the universe is visible. That means that most – well,  nearly all – of the universe is hidden behind veils of galaxies and clouds of hot gases; it is invisible, mysterious, perplexing.

NASA/CXC/CfA/STScI/ESO
This X-ray telescope image shows that dark matter (shown in blue)
makes up most of the mass of this galaxy.

Go out tonight in the dark and gaze upwards to the skies. Enjoy the wonder of the stars and moon. Then take a minute to contemplate the vast universe that we cannot see; that we can only guess is out there.

What miracles does it hold? What song does it sing?

As Carl Sagan once said:

Somewhere, something incredible is waiting to be known.


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