相关论文: Is Interstellar travel to an exoplanet Possible?
The discovery of exoplanets has both focused and expanded the search for extraterrestrial intelligence. The consideration of Earth as an exoplanet, the knowledge of the orbital parameters of individual exoplanets, and our new understanding…
Time is arguably the key limiting factor for interstellar exploration. At high speeds, flyby missions to nearby stars by laser propelled wafersats taking 50-100 years would be feasible. Directed energy launch systems could accelerate on the…
The modestly eccentric and non-coplanar orbits of the giant planets pose a challenge to solar system formation theories which generally indicate that the giant planets emerged from the protoplanetary disk in nearly perfectly circular and…
Civilization cannot sustain an exponential growth for long time even when neglecting numerous laws of physics! In this paper, we examine what are fundamental obstacles to long term survival of a civilization and its possibility to colonize…
The architecture of exoplanetary systems is often different from the solar system, with some exoplanets being in close orbits around their host stars and having orbital periods of only a few days. In analogy to interactions between stars in…
The habitable zones of low-mass stars are characterized by escape speeds that can be a few times higher than the Earth's orbit around the Sun. Owing to the exponential dependence of the required fuel mass on the terminal speed for chemical…
From wispy gas giants on the verge of disruption to tiny rocky bodies already falling apart, short-period exoplanets pose a severe puzzle to theories of planet formation and orbital evolution. By far most of the planets known beyond the…
Are there other planetary systems in our Universe? Indirect evidence has been found for planets orbiting other stars in our galaxy: the gravity of orbiting planets makes the star wobble, and the resulting periodic Doppler shifts have been…
A civilization in the habitable zone of a dwarf star might find it challenging to escape into interstellar space using chemical propulsion.
Human space exploration and settlement of other planets is becoming increasingly technologically feasible, while mission concepts for remote and crewed missions to nearby star systems continue to be developed. But the long-term success of…
Experience in exploring our own solar system has shown that direct investigation of planetary bodies using space probes invariably yields scientific knowledge not otherwise obtainable. In the case of exoplanets, such direct investigation…
With the availability of considerably more data, we revisit the question of how special our Solar System is, compared to observed exoplanetary systems. To this goal, we employ a mathematical transformation that allows for a meaningful,…
Searching for extraterrestrial life and supporting human life in space are traditionally regarded as separate challenges. However, there are significant benefits to an approach that treats them as different aspects of the same essential…
What kind of environment may exist on terrestrial planets around other stars? In spite of the lack of direct observations, it may not be premature to speculate on exoplanetary climates, for instance to optimize future telescopic…
Exoplanets number in their thousands, and the number is ever increasing with the advent of new surveys and improved instrumentation. One of the most surprising things we have learnt from these discoveries is not that small-rocky planets in…
Within the next few years, the first Earth-mass planets will be discovered around other stars. Some of those worlds will certainly lie within the classical "habitable zone" of their parent stars, and we will quickly move from knowing of no…
Co-orbital exoplanets are a by-product of the models of formation of planetary systems. However, none have been detected in nature thus far. Although challenging, the observation of co-orbital exoplanets would provide valuable information…
Are time-travels possible? is the past still existing? and is the future already existing? We try to give an answer to these an other questions concerning the properties of time and the close connection (but deep physical difference)…
Our ability to explore the cosmos by direct contact has been limited to a small number of lunar and interplanetary missions. However, the NASA Starlight program points a path forward to send small, relativistic spacecraft far outside our…
The great majority of exoplanets discovered so far are orbiting cool, low-mass stars whose properties are relatively similar to the Sun. However, the stellar magnetism of these stars can be significantly different from the solar one, both…