Gratitude is a duty which ought to be paid, but which none have a right to expect.

What's aero braking? That's a way to use the gravity and upper atmosphere of Earth to sling shot a ship out either deeper into space, or slow it down to be 'captured' by Earth's gravity.

If Mars formed life, then life on Earth could have been seeded by life on Mars, making every life form on Earth descended from Martians.

The misfortune of the wise is better than the prosperity of the fool.

Truth is mighty and will prevail. There is nothing wrong with this, except that it ain't so.