相关论文: Why Does Nature Form Exoplanets Easily?
The hundreds of exoplanets that have been discovered in the past two decades offer a new perspective on planetary structure. Instead of being the archetypal examples of planets, those of our Solar System are merely possible outcomes of…
The basic geometry of the Solar System -- the shapes, spacings, and orientations of the planetary orbits -- has long been a subject of fascination as well as inspiration for planet formation theories. For exoplanetary systems, those same…
For centuries, humanity wondered if there were other worlds like ours in the Universe. For about a quarter of a century, we have known that planetary systems exist around other stars, and more than 3800 exoplanetary systems have been…
Thousands of exoplanets have been discovered and the search for life outside Earth is at the forefront of astrophysical research. The planets we observe show a mind-blowing diversity that current theories strive to explain as part of the…
Exoplanet surveys have confirmed one of humanity's (and all teenagers') worst fears: we are weird. If our Solar System were observed with present-day Earth technology -- to put our system and exoplanets on the same footing -- Jupiter is the…
Most observed extrasolar planets have masses similar to, but orbits very different from, the gas giants of our solar system. Many are much closer to their parent stars than would have been expected and their orbits are often rather…
This article relates two topics of central importance in modern astronomy - the discovery some fifteen years ago of the first planets around other stars (exoplanets), and the centuries-old problem of understanding the origin of our own…
The apparent regularity of the motion of the giant planets of our solar system suggested for decades that said planets formed onto orbits similar to the current ones and that nothing dramatic ever happened during their lifetime. The…
Clouds also form in atmospheres of planets that orbit other stars than our Sun, in so-called extrasolar planets or exoplanets. Exoplanet atmospheres can be chemically extremely rich. Exoplanet clouds are therefor made of a mix of materials…
The study of planets outside our solar system may lead to major advances in our understanding of the Earth, and provide insight into the universal set of rules by which planets form and evolve. To achieve these goals requires applying…
It goes without saying that we are stuck with the universe we have. Nevertheless, we would like to go beyond simply describing our observed universe, and try to understand why it is that way rather than some other way. Physicists and…
Cosmos has always sparked human curiosity to unveil and speculate its fascinating secrets. This curiosity has ultimately opened a window to other worlds. After years of observation, computation, and data analysis, scientists have revealed…
Our galaxy is full with planets. We now know that planets and planetary systems are diverse and come with different sizes, masses and compositions, as well as various orbital architectures. Although there has been great progress in…
We give a popular account of the present state of the research in the field of extra-solar planetary systems, popularly termed as exoplanets, with a brief overview of the techniques employed. We also discuss the question of habitability and…
Here, we present a simple solution to problems that have plagued (extra)"galactic" astronomers and cosmologists over the last century. We show that "galaxy" formation, dark matter, and the tension in the expansion of the universe can all be…
As the number of detected extrasolar planets increases, exoplanet databases become a valuable resource, confirming some details about planetary formation, but also challenging our theories with new unexpected properties.
For centuries, our knowledge of planetary systems and ideas about planet formation were based on a single example, our solar system. During the last thirteen years, the discovery of ~170 planetary systems has ushered in a new era for…
After reviewing the difficulties faced by the conventional theory of planet formation (based upon the aggregation of microscopic dust particles), we describe an alternative hypothesis. We propose that planets form by gravitational collapse…
Recent discoveries of strongly misaligned transiting exoplanets pose a challenge to the established planet formation theory which assumes planetary systems to form and evolve in isolation. However, the fact that the majority of stars…
The planets of our solar system formed from a gas-dust disk. However, there are some properties of the solar system that are peculiar in this context. First, the cumulative mass of all objects beyond Neptune (TNOs) is only a fraction of…