An extrasolar planet or exoplanet is a planet orbiting a star (or remnant of a
star) beyond our Solar System. As of autumn 2007, about 250 exoplanets had been
discovered around 220 different stars, including nearly two dozen multiple planet
systems. No less than five exoplanets have been discovered orbiting the star 55
Cancri; one of the planets has nearly four times the mass of Jupiter, another is
comparable with Jupiter in mass, two are slightly less massive than Saturn, while
the innermost planet has a mass similar to that of Uranus....
The radiation of the sun in which the planet is incessantly plunged, penetrates
the air, the earth, and the waters; its elements are divided, change
direction in every way, and, penetrating the mass of the globe, would raise
its temperature more and more, if the heat acquired were not exactly
balanced by that which escapes in rays from all points of the surface and
expands through the sky.
As of June 2002, astronomers had discovered more than
100 other planets orbiting distant suns. With advances in tech-
nology, that number will surely increase during the opening
decades of the twenty-first century. Although our explorations
of the Cosmos hold great promise of future discoveries, among
all of the known worlds, Earth remains unique. Thus far it is the
only known planet with blue skies, warm seas, and life.
Oceanography is a very complex science.
Its field study, the knowledge of the oceans and the seas and their physical and
biological characteristics, is fundamental to comprehend many oceanographic and
ecological aspects that directly influence the human life and the planet health.
From micro-scale, like coastal processes, to macro-scale, like Global Change, the
oceans, the seas and the marine life, play the main role to maintain the earth
equilibrium, both from a physical and a chemical point of view (e.g. carbon cycle and
water masses dynamic)....
How can you tell if a technology has reached critical mass?
Easy: you look at how much damage it’s causing. Pretty
much every human invention is neutral in itself; any benefits
(or drawbacks) come from the way it’s used: atomic
energy can be used to power a city or destroy it; cars make it travel
over distances that were unthinkable just a hundred years ago
possible, and are happily destroying our planet with their polluting
Abstract: “Brown dwarfs” is the collective name for objects more massive than giant
planets such as Jupiter but less massive than M dwarf stars. This review gives a brief
description of the classification and chemistry of low mass dwarfs. The current spectral
classification of stars includes L and T dwarfs that encompass the coolest known stars
and substellar objects. The relatively low atmospheric temperatures and high total
pressures in substellar dwarfs lead to molecular gas and condensate chemistry.
Physical theories allow us to make predictions: given a complete description of a physical
system, we can predict the outcome of some measurements. This problem of predicting
the result of measurements is called the modelization problem, the simulation problem,
or the forward problem. The inverse problem consists of using the actual result of some
measurements to infer the values of the parameters that characterize the system.
While the forward problemhas (in deterministic physics) a unique solution, the inverse
problem does not.
Since the time of Newton the basic structure of the solar system and the laws
that govern the motions of the bodies within it have been well understood. One
central body, the Sun, containing most of the mass of the system has a family of
attendant planets in more-or-less circular orbits about it. In their turn some of
the planets have accompanying satellites, including the Earth with its single satellite,
the Moon. With improvements in telescope technology, and more recently
through space research, knowledge of the solar system has grown apace.
Having explored and mapped our planet's land masses, vast oceans and the space surrounding it, science is turning inward to the challenging and controversial mapping of the human genome, a collection of genes forming DNA. Each of our genes is a single instruction for the make-up of an individual being. The more we learn, the more we discover to explore - and the more controversy we release in the process.
Astronomy is the most ancient science humans have practiced on Earth.
It is a science of extremes and of large numbers: extremes of time – from the
big bang to infinity –, of distances, of temperatures, of density and masses,
of magnetic field, etc.
IF YOU will look at any good map of Venus you will see that the land
mass called Anlap lies northwest of the island of Vepaja, from which
Duare and I had just escaped. On Anlap lies Korva, the friendly country
toward which I pointed the nose of our plane.
Of course there is no good map of Venus, at least none that I ever have
seen; because the scientists of the southern hemisphere of the planet, the
hemisphere to which Chance carried my rocket ship, have an erroneous
conception of the shape of their world. They believe that Amtor, as they
call it, is shaped like a...
Four hundred years ago, the Universe changed. Or, at least,
our perception of it did, thanks to Galileo Galilei’s scrutiny
of the night sky with a telescope. Within a couple
of years, his observations of the Moon, phases of Venus and
satellites of Jupiter shattered the old Ptolemaic model of our
Solar System. To the church’s dismay, Earth assumed its rightful place
as one of several planets orbiting the Sun (see page 28).
Marking Galileo’s anniversary, the International Year of Astronomy
seeks to remind us of the humbling nature of gazing at the heavens.