# Back to the nineties!

I've left the world before the 90's,
But I'm still many a ninety.
Inside me there's an instant,
I've proposed many a constant.
My universe is not stable,
But I'm still there at the table.

What's my name?

These are some theories that relate this to

Albert Einstein

I've left the world before the 90's,

The Einstein Observatory was an X-ray telescope launched into space in 1978 which re-entered the Earth's atmosphere and burned up in 1982.

But I'm still many a ninety.

The element Einsteinium has atomic number ninety-nine (many a ninety).

Inside me there's an instant,

Einstein includes the instant abbreviation inst.

I've proposed many a constant.

Einstein's gravitational constant κ , the cosmological constant Λ and the constant speed of light c.

My universe is not stable,

Einstein abandoned his proposed static universe after Hubble's observations of the galaxies' red-shifts, and his General theory of relativity may describe an expanding Universe.

But I'm still there at the table.

His general theory is unsurpassed - or ein (one in German) and stein - a beer mug.

Title: Back to the nineties!

Einstein is a rearrangement of nineties.

• I think the "table" bit refers to the periodic table of the elements. – Mr Lister Jul 14 at 6:17

Are you a

floppy disk?

I've left the world before the 90's

A floppy disk was made around the 70s and discontinued in the 2000s due to mainly USB flash drives etc (I think it left earlier than that, actually, but many people kept them as collectibles, though they are officially obsolete nowadays).

But I'm still many a ninety.

You could have listened to many 90s songs with one!

Inside me there's an instant,

Back then it used to be "high-tech" and work in an "instant" so to speak.

I've proposed many a constant.

With one, you could also distribute software; transfer files; and back up data.

My universe is not stable,

It is "floppy" and not used anymore.

But I'm still there at the table.

These were used because hard-drives were very expensive, but now, if you have one.... it looks like a plate without its protective covering, but plates go on the table (not really at the table).

• Very nice, except for the "You could have listened to many 90s songs with one!" part. Given that the average MP3 doesn't fit on a floppy... – Mr Lister Jul 14 at 6:15
• @MrLister really? I didn't know that. I've never heard of one during this riddle, but when I asked my dad, he told me this and I was like, "What's that???" He told me he used to have one where he could listen to songs with it, so thanks for being more accurate and clearing my misunderstanding :P – Mr Pie Jul 14 at 8:39
• @MrLister Depending on the size, the bigger ones can fit a mp3 (I think) – VFDan Jul 14 at 21:01