関連する実験動画
Updated: Feb 18, 2026

11:34
Scattering And Absorption of Light in Planetary Regoliths
Published on: July 1, 2019
11.0K
赤色で非常に長い星間小惑星からの短い訪問
Karen J Meech1, Robert Weryk1, Marco Micheli2,3
1Institute for Astronomy, 2680 Woodlawn Drive, Honolulu, Hawaii 96822, USA.
Nature
|November 22, 2017
まとめ
観測された最初の星間物体
科学分野:
- 天文学と天体物理学
- 惑星科学
背景:
- 太陽系形成モデルでは 惑星粒子が星間空間へ放出されると予測されている.
- 過去の探査では 予測された密度にもかかわらず 星間天体が見つかりませんでした
- 太陽系物質を他の惑星系のものと比較する方法は存在しなかった.
研究 の 目的:
- 1I/2017 U1 (オウムアムア) の太陽系外起源を確認する.
- 異なる惑星系からの物質の比較分析を可能にします.
- 星間天体の数と特性を評価する.
主な方法:
- 太陽系外起源を特定するための軌道の分析
- 表面組成のスペクトル測定
- 形状とサイズを判別するための光曲線観測.
主要な成果:
- オウミュアウの軌道は太陽系外だ
- 彗星活動のない小惑星の特徴を示した.
- 表面は赤色で,非常に長方形の形状 (長さと幅の比10:1) であり,半径は推定102mである.
- この物体の大きさは 既知の太陽系の物体の中で前例のないものです
結論:
- "オウムアムア"の発見は 星間天体の存在を証明した.
- 恒星間物体の密度に関する以前の推定は過小評価されているかもしれない.
- 他の惑星系からの物質を研究する ユニークな機会を与えてくれます
- 将来の観測では 改良された機器で より多くの星間天体を検出できるでしょう
関連する概念動画
Eccentricity of an Ellipse
384
An ellipse is a fundamental conic section defined by the constant sum of distances from any point on its curve to two fixed points, known as the foci. This geometric property can be physically demonstrated using a pencil, string, and two pins. By anchoring the string at both ends and maintaining it taut with a pencil, one can trace the outline of an ellipse.The shape and extent of the ellipse are determined by its eccentricity, e, defined as the ratio of the distance between the center and a...
384
The Structure of Intermediate Filaments
5.8K
The intermediate filaments are one of three widely studied cytoskeletal filaments. They are so named as their diameter (10 nm) is in between that of microfilaments (7 nm) and the microtubules (25 nm). These filaments are highly stable and can remain intact when exposed to high salt concentrations and detergents. These filaments are responsible for providing stability and mechanical support to the cells. They also help in cell adhesion and maintaining tissue integrity.
Intermediate...
Intermediate...
5.8K
Lampbrush Chromosomes
8.8K
In 1882, Flemming observed lampbrush chromosomes (LBC) in salamander eggs. Later in 1892, Rückert observed LBCs in shark egg cells and coined the term "lampbrush chromosomes" because they looked like brushes used to clean kerosene lamps.
LBCs are made up of two pairs of conjugating homologous chromatids. Each chromatid consists of alternatively positioned regions of condensed-inactive chromatin and loosely placed-active side loops, which can be contracted and extended. The loops...
LBCs are made up of two pairs of conjugating homologous chromatids. Each chromatid consists of alternatively positioned regions of condensed-inactive chromatin and loosely placed-active side loops, which can be contracted and extended. The loops...
8.8K
Ellipses
320
An ellipse is formed when a right circular cone is intersected by an inclined plane that does not cut through its base. This intersection yields a closed, symmetric curve characterized by distinctive geometric properties. Most notably, an ellipse is defined as the collection of all points in a plane for which the combined distances to two fixed points—called the foci—remain constant.The ellipse features two principal axes: the major and the minor axes. The major axis is the longest...
320
Surface Appendages of Archaea
710
Archaeal surface appendages are highly specialized structures essential for environmental adaptation, encompassing roles in adhesion, biofilm formation, and motility. Among these appendages, pili and archaella stand out for their distinct morphologies and functionalities, enabling archaea to thrive in diverse and often extreme environments.Pili: Adhesion and Biofilm FormationPili are filamentous structures assembled from pilin protein subunits, primarily contributing to adhesion and biofilm...
710
Kepler's First Law of Planetary Motion
5.7K
In the early 17th century, German astronomer and mathematician Johannes Kepler postulated three laws for the motion of planets in the solar system. He formulated his first two laws based on the observations of his forebears, Nikolaus Copernicus and Tycho Brahe.
Polish astronomer Nikolaus Copernicus put forth a theory that stated a heliocentric model for the solar system. According to this heliocentric theory, all the planets, including Earth, orbit the Sun in circular orbits.
On the other hand,...
Polish astronomer Nikolaus Copernicus put forth a theory that stated a heliocentric model for the solar system. According to this heliocentric theory, all the planets, including Earth, orbit the Sun in circular orbits.
On the other hand,...
5.7K

