地球价值3千万亿英镑 全宇宙最高
美国加州大学圣克鲁兹分校的一位天体物理学教授利用自创的公式计算出了宇宙中不同天体的价值，其中地球价值为3千万亿英镑，是最贵的一个，火星的价值只有1万英镑，而金星则一文不值。
A scientist has created a formula to calculate the worth of planet Earth and has valued it at three thousand trillion pounds.
Astrophysicist（天体物理学家） Greg Laughlin came up with the figure by calculating the sum of the planet’s age, size, temperature, mass and other vital statistics – and Earth came out as the most expensive.
Mars was only valued at £10,000, while Venus is said to be worth less than a penny.
There are about 1,235 other planets in the universe, most of which weren’t given a high price tag because of their inhospitable（荒凉的，冷淡的） climates.
Professor Laughlin from the University of California-Santa Cruz invented the equation（方程式） , which he used to evaluate the discoveries made by Nasa’s £600 million Kepler spacecraft .
The planet-hunting spacecraft went into orbit two years ago and a year later Laughlin decided to create price tags for the terrestrial planets（类地行星） that Keplar was set to discover.
At the time, the exoplanet（外部行星） Gilese 581 c was considered the most Earth-like world known to scientists, but the equation only valued it at £100, while KOI 326.01 is said to be worth £150,000.
Laughlin told science writer Lee Billings last week: ‘I’ve just always thought that the concept of an ‘Earth-like planet in the habitable zone’ was pretty vaguely（含糊地） defined, and I wanted a metric（度量标准） that I could plug a planet into to see whether its value was high enough to warrant media hype（媒体炒作） .
‘This is just a way for me to be able to quantify how excited I should be about any particular planet.’
The older the star, the more value it has because it has had the chance to mature, the mass is then taken into account and generally if it’s around the same size as Earth it is thought of as a good size for supporting life.
Laughlin also took into account the amount of energy the star creates and whether its temperatures could also support life.
The professor concluded that planets with a value of £60 million or more are worth studying but the ones worth less aren’t.
He also said: ‘The formula makes you realise just how precious Earth is and I hope it will help us as a society safeguard what we have.