299,792,458 meters per second

What you see isn’t real.

Ok that’s over egging it a little.

What you see is not reality now.

When you look in the mirror that’s not exactly how your face looks when you see it.  The light took just over 1 billionth of a second to reflect from face to mirror to eye.  Frankly you’ve changed.

Man in the mirror

Monday morning was delayed by a nanosecond while the light caught up with his face….

Everything you can see, what you perceive as now, is actually the past.  You stand at the tip of a history bathed in light unable to actually see what is truly in front of you.

Ok, stretching the point perhaps.  Essentially true, but perhaps meaningless in everyday experience.

The Sun is 8 minutes away, but that matters little to most.

Light has a speed limit so incredibly fast that it is essentially instantaneous when you are rubbing your eyes in the mirror on Monday morning.

Last week a star died.

nova is sagittarius 7th July 2012

Star Death. Possible Nova ins Sagittarius. Credit: AAVSO

This is true.  But not the star we saw die.

Last week we saw a star die, but it’s death was an ancient event.

Last week we finally received news of a star’s death.

Some stars we still see shining in the sky are dead.  Like watching historical footage we are seeing their light stream towards us and following behind is a grand finale, perhaps an incredibly bright flash or a dramatic change in shape and colour.

We look at Betelgeuse and know that it is a star near its end.  Swollen, deep red, even to the naked eye you can imagine that it looks angry.

Betelgeuse Hubble image

Grrrrr! Angry face Betelgeuse imaged by Hubble. NASA

Is it still there?

Racing towards us at 299,792,458 meters per second somewhere in the space between us the light from the catastrophic death of this familiar star may already exist.

Or maybe what we see is still reality.

(Can I recomend a little follow up read here, did you know your brain compensates for some of the time delay!?)

About astronomersden

Daddy, Hubby, Teacher and when ever I get the chance Astronomer.
This entry was posted in Astronomy, Orion, Sun, The Astronomer's Den and tagged , , , , , . Bookmark the permalink.

3 Responses to 299,792,458 meters per second

  1. Wedge7 says:

    Nice post. I do love the fact that when we look up at the stars, we’re seeing the past. It amazes me every time I think about it. I wrote a post a while ago about how light from the sun is ancient (170,000 years or so), and how we are actually seeing the future the whole time, rather than the past, due to the time it takes for light to travel from your eye to your brain. Blog post is entitled “Ancient Sunlight & Time Bending Brains”, if you fancy a short read!

  2. Something to think about when I’m brushing my teeth in the morning!

  3. Pingback: A Festival of Light | astronomersden

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