Earth Climate

Considering the debate about the global warming there are some curiosities that is interesting to know.

Did you know that if you compare to the historic climate of the earth that we have an unusual amount of ice at the moment? We have permanent ice at both the poles, 10 % of the area of our earth is covered by ice and 75 % of all fresh water is ice. Actually the most common state of our planet has been to have no permanent ice at all. Technically we are currently still in an ice age.

Regarding the discussions about the global warming it not really about the current state of the temperature it’s about the change.

Just like Michael E. Mann comments in this article:

Its not the absolute state as much as the rate of change, which presents the real challenges and threats.

By the way if you have a good idea about how to remove anthropogenic, atmospheric greenhouse gases you can win a price of 25 million dollars at the Virgin Earth Challange. 🙂

Encryption

I just played around with Kmail and tried to use it’s GPG integration. GPG stands for Gnu Privacy Guard and can help you to verify that who sent a mail really is the one he claims or you can send encrypted messages to someone. It all works with keys, if you have not used this before all talk about public and private keys, key rings, key servers, algorithms, encryption and decryption can all be quite confusing. I’ll try to make a short simple explanation.

The first thing you do when you have installed GPG is to generate your private and public keys. So on your machine you will have 2 key files, one is called your private key and one is called your public key. You can give your public key to whoever you want, there is nothing secret with it, but you should keep your private key safe and never send it to anyone. I once read about a way to better memorize what the keys are for ( can’t remember the source ), but you can think of your keys like this:

The private key is The Key
The public key is The Lock
As described above you have one key and one lock, and your key can open the lock. Think of the lock as a padlock.

So lets say you have a friend that wants to send you a secret message that he wants only you to be able to read. A secure process of transfer the secret message must be of such a kind such that if a third person looks at the data that you and James exchanges it would be of no help to him. But James must give you an encrypted message and he must also know that you can decrypt and read it.

If you disregard the computer files and algorithms and all that and just think of it as physical keys and padlocks it’s easier to grasp. So what you do is to send James your padlock (opened). When James receives the padlock from you he takes out a box that he has and puts the secret message inside the box and then locks the box with your padlock. Now he can send the message back to you. When you now receive the locked box you can use your key that fits the padlock and open the box and read the message.

In this way the third person only sees one lock going one way and one locked box going the other way. He never sees any key being sent between you and James and thus he can not get to the message.

In GPG terms this process would be, you send your public key to James and he encrypts his message with your public key and sends the encrypted message back to you. You use your private key to decrypt the message.

Anyway even though I find this interesting and good to know I can’t say that I have ever felt the need to send someone an encrypted mail. But if software makes this easy enough it would probably be more used, as it is today it is often a bit too cumbersome to use unless you must say something really really secret to someone.