Considering hypothetical co-orbital asteroids with the Earth, Tatum (1997) presented a study about the necessary radial distance in order to produce collision. He adopted an analysis considering a composition of circular two-body systems, Sun-Earth and Sun-Asteroid. He found that asteroids with radial positions between 0.9943 and 1.0057 AU would necessarily collide with the Earth. In the presen...

In around 5 gigayears our Sun will grow to a Red Giant and will swallow Earth. In this article we present a rescue-plan for the whole mankind, including its inherited habitat Earth. The plan is subdivided into two parts: If we content ourselves to survive only the next 5 Gy (until the shellburning phase of our Sun) we propose to construct some kind of parasol to shadow Earth rather than to move...

The result of a long-term experiment is presented and discussed. The experiment aimed at testing the hypothesis that radioactive β-decay might be caused by the omnipresent neutrino flux coming from the sun and other sources, by trying to find a positive correlation between the decay rate of tritium and the annually varying solar neutrino flux, due to the annually changing distance from sun to e...

Simultaneous observations of the solar wind velocity as measured at the Pioneer 9 and Ogo 5 spacecraft during five solar rotations in 1968 and 1969 are presented. During this time, Pioneer 9 was traveling in toward the sun to approximately 0.7 AU while the earth orbiter Ogo 5 was spending long periods in the interplanetary medium. A comparison of the 3-hour averages of solar wind velocity obtai...

In the third century B.C.E., Eratosthenes of Cyrene made a famous measurement of the circumference of the Earth. This was not the first such measurement, but it is the earliest for which significant details are preserved. Cleomedes gives a short account of Eratosthenes' method, his numerical assumptions, and the final result of 250,000 stades. However, many ancient sources attribute to Eratosth...

We assume that if the sun has a companion, it has a period of 27 Myr corresponding to the periodicity seen in cometary impacts on earth. Based on this assumption, it is seen that the inner Lagrengian point of the interaction between the Sun and its companion is in the Oort cloud. From this we calculate the mass – distance relation for the companion. We then compute the expected apparent magnitu...

In the 3 century BCE, the Greek mathematician Eratosthenes was able to estimate the Earth’s circumference. He learned that on the summer solstice the Sun at noon was reflected in a deep well in the southern Egyptian city of Syene, which indicated that the Sun was directly overhead at that time. He also knew the Sun was not directly overhead at that time where he lived (Alexandria, in northern E...

By nodal regression and apsidal precession, the Earth flattering at satellite low Earth orbits (LEO) is manifested. Nodal regression refers to the shift of the orbit’s line of nodes over time as Earth revolves around the Sun. Nodal regression is orbit feature utilized for circular orbits to be Sun synchronized. A sun-synchronized orbit lies in a plane that maintains a fixed angle with respect t...

WE STAND ON A GREAT DIVIDE in the detection and study of exoplanets. On one side of this divide are the hundreds of known massive exoplanets, with measured densities and atmospheric temperatures for a handful of the hottest exoplanets. On the other side of the divide lies the possibility, as yet unrealized, of detecting and characterizing a true Earth analogue—an Earth-like planet (a planet of ...

Public understanding of climate and climate change is of broad societal importance. However, misconceptions regarding reasons for the seasons abound amongst students, teachers, and the public, many of whom believe that seasonality is caused by large variations in Earth’s distance from the Sun. Misconceptions may be reinforced by textbook illustrations that exaggerate eccentricity or show an inc...