23 research outputs found
Exploring the Bimodal Solar System via Sample Return from the Main Asteroid Belt: The Case for Revisiting Ceres
Abstract: Sample return from a main-belt asteroid has not yet been attempted, but appears technologically feasible. While the cost implications are significant, the scientific case for such a mission appears overwhelming. As suggested by the “Grand Tack” model, the structure of the main belt was likely forged during the earliest stages of Solar System evolution in response to migration of the giant planets. Returning samples from the main belt has the potential to test such planet migration models and the related geochemical and isotopic concept of a bimodal Solar System. Isotopic studies demonstrate distinct compositional differences between samples believed to be derived from the outer Solar System (CC or carbonaceous chondrite group) and those that are thought to be derived from the inner Solar System (NC or non-carbonaceous group). These two groups are separated on relevant isotopic variation diagrams by a clear compositional gap. The interface between these two regions appears to be broadly coincident with the present location of the asteroid belt, which contains material derived from both groups. The Hayabusa mission to near-Earth asteroid (NEA) (25143) Itokawa has shown what can be learned from a sample-return mission to an asteroid, even with a very small amount of sample. One scenario for main-belt sample return involves a spacecraft launching a projectile that strikes an object and flying through the debris cloud, which would potentially allow multiple bodies to be sampled if a number of projectiles are used on different asteroids. Another scenario is the more traditional method of landing on an asteroid to obtain the sample. A significant range of main-belt asteroids are available as targets for a sample-return mission and such a mission would represent a first step in mineralogically and isotopically mapping the asteroid belt. We argue that a sample-return mission to the asteroid belt does not necessarily have to return material from both the NC and CC groups to viably test the bimodal Solar System paradigm, as material from the NC group is already abundantly available for study. Instead, there is overwhelming evidence that we have a very incomplete suite of CC-related samples. Based on our analysis, we advocate a dedicated sample-return mission to the dwarf planet (1) Ceres as the best means of further exploring inherent Solar System variation. Ceres is an ice-rich world that may be a displaced trans-Neptunian object. We almost certainly do not have any meteorites that closely resemble material that would be brought back from Ceres. The rich heritage of data acquired by the Dawn mission makes a sample-return mission from Ceres logistically feasible at a realistic cost. No other potential main-belt target is capable of providing as much insight into the early Solar System as Ceres. Such a mission should be given the highest priority by the international scientific community
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Supreme Court Law Clerks' Recollections of Brown v. Board of Education
On May 17, 1954, the Supreme Court decided in Brown v. Board of Education that state laws segregating public school children by race were unconstitutional. Chief Justice Earl Warren of course wrote Brown for a unanimous Court, and Brown is generally regarded as among the most significant decisions in United States history.
As the Supreme Court was considering Brown and its companion cases, the Justices agreed not to discuss them with others - not even their own law clerks. As a result, many of the thirty-six young men who worked as clerks during the Court's October Terms 1952 and 1953 were not privy to very much, in the segregation cases, of the Justices' thinking, work, discussions, votes and draft opinions. This secrecy system did, however, have exceptions. Some of the Justices, including Chief Justice Warren and Associate Justices Stanley F. Reed, Robert H. Jackson and Felix Frankfurter, gave assignments to and in varying ways confided in their respective law clerks as the Court wrestled with and ultimately decided the unconstitutionality of school segregation.
In late April 2004, a few weeks prior to Brown's 50th anniversary, the Robert H. Jackson Center in Jamestown, New York, assembled four attorneys, former law clerks to the Justices named above, for a group discussion of Brown. This was the first occasion on which these former clerks had, together, assembled and compared their recollections of the Brown decision-making process inside the Supreme Court.
In the discussion, edited and introduced for publication, these "insiders" explain how the Justices came to decide Brown as they did, individually and as a Court. The discussion illuminates particularly well the process and chronology of developments by which Chief Justice Warren wrote his Brown opinion and other Justices decided not to write separately and also not to dissent, resulting in the unanimous Court