5. The threat from space

2014 ◽  
pp. 88-109
Author(s):  
Bill McGuire
Keyword(s):  
Circular Orbits ◽  
Asteroid Impact ◽  
The Earth ◽  
The Future ◽  
Near Earth Asteroids ◽  
Earth Potential ◽  
Asteroids And Comets

‘The Threat from Space’ considers the threat of asteroids and comets colliding with Earth. Potential impacts of Near Earth Asteroids, with almost circular orbits, have been identified, but the threat from comets, which follow strongly elliptical paths, is uncertain. The Mexican asteroid impact 65 million years ago is thought to have wiped out two-thirds of all species living at the time. The Earth will be hit again at some point in the future, but how will it affect us? This will depend upon three things: the size of the object, how quickly it is travelling, and whether it hits the land or the ocean.

scholarly journals Searching for Neas from Earth or Space

1998 ◽  
Vol 11 (1) ◽  
pp. 257-261
Author(s):  
A.W. Harris
Keyword(s):  
Past Experience ◽  
The Earth ◽  
The Future ◽  
Near Earth Asteroids

Abstract Different options for searching for near-Earth asteroids that may pose an impact hazard to the Earth in the future are discussed. The space option has not been studied in as much detail as the ground-based survey option, so a more detailed study of the space option might be appropriate. It is not evident, however, that a space-based system can be competitive or superior to the ground-based option, because past experience argues very strongly to the contrary.

scholarly journals Near-Earth Asteroids on Archival Schmidt Plates

1995 ◽  
Vol 148 ◽  
pp. 170-173
Author(s):  
R. H. McNaught ◽  
D. I. Steel ◽  
K. S. Russell ◽  
G. V. Williams
Keyword(s):  
Wide Field ◽  
Schmidt Telescope ◽  
Field Plate ◽  
The Earth ◽  
Routine Identification ◽  
Scientific Results ◽  
Near Earth Asteroids ◽  
Asteroids And Comets

AbstractWe describe our routine identification of images of asteroids and comets on plates and films in the U.K. Schmidt Telescope archive. The asteroids of most interest to us are those which approach the Earth, and whenever such an object is found (by anyone) we perform backintegrations in order to determine whether the object may have been recorded on any UKST plate taken since 1973. In many cases the object is found (‘precovered’) and measured, allowing an accurate orbit to be determined soon after its discovery; other studies such as long-term dynamical investigations, or predictions of future close approaches to the Earth, are then possible. Similar programs using other wide-field plate archives are to be encouraged, since valuable scientific results may be derived.

Statistical results on discovered near-Earth asteroids

1999 ◽  
Vol 173 ◽  
pp. 81-86
Author(s):  
S. Berinde
Keyword(s):  
Dynamical Evolution ◽  
Minor Planet ◽  
Orbital Elements ◽  
The Earth ◽  
Near Earth Asteroids ◽  
Statistical Results

AbstractThe first part of this paper gives a recent overview (until July 1st, 1998) of the Near-Earth Asteroids (NEAs) database stored at Minor Planet Center. Some statistical interpretations point out strong observational biases in the population of discovered NEAs, due to the preferential discoveries, depending on the objects’ distances and sizes. It is known that many newly discovered NEAs have no accurately determinated orbits because of the lack of observations. Consequently, it is hard to speak about future encounters and collisions with the Earth in terms of mutual distances between bodies. Because the dynamical evolution of asteroids’ orbits is less sensitive to the improvement of their orbital elements, we introduced a new subclass of NEAs named Earth-encounter asteroids in order to describe more reliably the potentially dangerous bodies as impactors with the Earth. So, we pay attention at those asteroids having an encounter between their orbits and that of the Earth within 100 years, trying to classify these encounters.

When Silence Strikes: Derrida, Heidegger, Mallarmé

2018 ◽  
Vol 40 (2) ◽  
pp. 238-262
Author(s):  
Rodrigo Therezo
Keyword(s):  
The Earth ◽  
The Future ◽  
The Way

This paper attempts to rethink difference and divisibility as conditions of (im)possibility for love and survival in the wake of Derrida's newly discovered—and just recently published—Geschlecht III. I argue that Derrida's deconstruction of what he calls ‘the grand logic of philosophy’ allows us to think love and survival without positing unicity as a sine qua non. This hypothesis is tested in and through a deconstructive reading of Heidegger's second essay on Trakl in On the Way to Language, where Heidegger's phonocentrism and surreptitious nationalism converge in an effort to ‘save the earth’ from a ‘degenerate’ Geschlecht that cannot survive the internal diremption between Geschlechter. I show that one way of problematizing Heidegger's claim is to point to the blank spaces in the ‘E i n’ of Trakl's ‘E i n Geschlecht’, an internal fissuring in the very word Heidegger mobilizes in order to secure the future of mankind.

Dombey and Son

2008 ◽  
Author(s):  
Charles Dickens ◽  
Dennis Walder
Keyword(s):  
Family Relationships ◽  
The Sun ◽  
The Novel ◽  
The Earth ◽  
The Future ◽  
Original Illustrations ◽  
The One

Dombey and Son ... Those three words conveyed the one idea of Mr. Dombey's life. The earth was made for Dombey and Son to trade in, and the sun and moon were made to give them light.' The hopes of Mr Dombey for the future of his shipping firm are centred on his delicate son Paul, and Florence, his devoted daughter, is unloved and neglected. When the firm faces ruin, and Dombey's second marriage ends in disaster, only Florence has the strength and humanity to save her father from desolate solitude. This new edition contains Dickens's prefaces, his working plans, and all the original illustrations by ‘Phiz’. The text is that of the definitive Clarendon edition. It has been supplemented by a wide-ranging Introduction, highlighting Dickens's engagement with his times, and the touching exploration of family relationships which give the novel added depth and relevance.

scholarly journals New Tools for the Optimized Follow-Up of Imminent Impactors

Universe ◽  
2021 ◽  
Vol 7 (1) ◽  
pp. 10
Author(s):  
Maddalena Mochi ◽  
Giacomo Tommei
Keyword(s):  
Orbit Determination ◽  
Main Belt ◽  
Impact Monitoring ◽  
The Earth ◽  
Current Observation ◽  
Short Period ◽  
Fly Eye ◽  
Near Earth Asteroids ◽  
Near Earth Objects

The solar system is populated with, other than planets, a wide variety of minor bodies, the majority of which are represented by asteroids. Most of their orbits are comprised of those between Mars and Jupiter, thus forming a population named Main Belt. However, some asteroids can run on trajectories that come close to, or even intersect, the orbit of the Earth. These objects are known as Near Earth Asteroids (NEAs) or Near Earth Objects (NEOs) and may entail a risk of collision with our planet. Predicting the occurrence of such collisions as early as possible is the task of Impact Monitoring (IM). Dedicated algorithms are in charge of orbit determination and risk assessment for any detected NEO, but their efficiency is limited in cases in which the object has been observed for a short period of time, as is the case with newly discovered asteroids and, more worryingly, imminent impactors: objects due to hit the Earth, detected only a few days or hours in advance of impacts. This timespan might be too short to take any effective safety countermeasure. For this reason, a necessary improvement of current observation capabilities is underway through the construction of dedicated telescopes, e.g., the NEO Survey Telescope (NEOSTEL), also known as “Fly-Eye”. Thanks to these developments, the number of discovered NEOs and, consequently, imminent impactors detected per year, is expected to increase, thus requiring an improvement of the methods and algorithms used to handle such cases. In this paper we present two new tools, based on the Admissible Region (AR) concept, dedicated to the observers, aiming to facilitate the planning of follow-up observations of NEOs by rapidly assessing the possibility of them being imminent impactors and the remaining visibility time from any given station.

Climate-vegetation-fire interactions and feedbacks: trivial detail or major barrier to projecting the future of the Earth system?

2016 ◽  
Vol 7 (6) ◽  
pp. 910-931 ◽  
Author(s):  
Rebecca M. B. Harris ◽  
Tomas A. Remenyi ◽  
Grant J. Williamson ◽  
Nathaniel L. Bindoff ◽  
David M. J. S. Bowman
Keyword(s):  
Earth System ◽  
Major Barrier ◽  
The Earth ◽  
The Future

INFLUENCE OF MAGNETIC CHARGE ON THE SAGNAC EFFECT IN THE BARDEEN SPACETIME

2021 ◽  
Vol 0 (1) ◽  
pp. 92-96
Author(s):  
R.KH. KARIMOV ◽  
◽  
K.K. NANDI ◽  
Keyword(s):  
Black Hole ◽  
Light Source ◽  
Magnetic Charge ◽  
Sagnac Effect ◽  
Modified Theories Of Gravity ◽  
Circular Orbits ◽  
The Earth ◽  
Astrophysical Objects ◽  
Interesting Task ◽  
Theories Of Gravity

This paper investigates one of the most interesting effects associated with the rotation of astrophysical objects (the Sagnac effect). The effect was first confirmed in laboratory experiments by Georges Sagnac with a rotating ring interferometer in 1913. Later, the effect was also confirmed within the framework of the Earth in the "Around-the-World" experiment conducted by J. Hafele and R. Kitting, in which they twice circled the Earth with an atomic cesium clock on board and compared the "flying" clock with those remaining static on the Earth. As a result, a non-zero difference in the clock rate was found as a confirmation of the Sagnac effect. Subsequently, more precise satellite experiments have been carried out to measure the Sagnac effect within the Earth. The effect was also considered in general relativity and modified theories of gravity, where many works were carried out to study the influence of such parameters as angular momentum, cosmological constant, Ricci scalar, etc. on the Sagnac effect. An interesting task is to study the influence of a magnetic charge on the effect, since the solution with rotation described by a black hole with mass M and magnetic charge g is the Bardeen nonsingular black hole. The work will calculate the Sagnac effect in the space-time of the rotating Bardeen black hole for both geodesic and non-geodesic circular orbits of the light source / receiver (assuming that the light source and receiver are defined at the same point). Two types of circular orbits describe the opposing influence on the Sagnac effect: the Sagnac delay increases with an increase in the magnetic charge in the case of non-geodesic circular orbits and decreases in the case of geodesic circular orbits. However, the farther is the orbit of the light source / receiver, the less the magnetic charge affects the Sagnac delay. It is also assumed that the gravity of the Earth and the Sun near the surface is well described by the Bardeen metric.

scholarly journals Alan Betts: Green Energy Times, 2018

2019 ◽  
Author(s):  
Alan Betts
Keyword(s):  
Climate Change ◽  
Energy Policy ◽  
Climate Science ◽  
Green Energy ◽  
Collective Decision ◽  
The Public ◽  
Systems Perspective ◽  
Climate Change Denial ◽  
The Earth ◽  
The Future

This is a collection of my 2018 articles in the Green Energy Times (http://www.greenenergytimes.org/ ).This series started in 2016. Many of these articles have been edited or updated from articles I wrote forthe Rutland Herald, sometimes with different titles and pictures.They blend science and opinion with a systems perspective, and encourage the reader to explorealternative and hopeful paths for their families and society. They are written so that a scientist willperceive them as accurate (although simplified); while the public can relate their tangible experience ofweather and climate to the much less tangible issues of climate change, energy policy and strategies forliving sustainably with the earth system.The politically motivated attacks on climate science by the current president have sharpened my politicalcommentary this year; since climate change denial may bring immense suffering to our children and lifeon Earth.I believe that earth scientists have a responsibility to communicate clearly and directly to the public1 –aswe all share responsibility for the future of the Earth. We must deepen our collective understanding, sowe can make a collective decision to build a resilient future.

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