関連する実験動画
Updated: Feb 10, 2026
02:31
Phase Transitions and Effect of Intermolecular Forces
23.3K
ラブラドール (カナダ) の3.95億年前の堆積岩からの初期の生命の痕跡
Takayuki Tashiro1, Akizumi Ishida2,3, Masako Hori2,4
1Department of Earth Science and Astronomy, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo 153-8902, Japan.
Nature
|September 30, 2017
まとめ
研究者達は39億5千万年前の岩石で 生命の最も古い証拠である 生物学的石墨を発見しました ラブラドールのこの発見は 地球上の生命の初期と 他の惑星の可能性について 新たな洞察をもたらします
科学分野:
- 地化学
- 天体生物学
- 地球の初期状態
背景:
- 生命の起源を理解するために,エオルカイアン時代の岩石を調査することは極めて重要です.
- 初期の生命の重要な指標である生物学的石墨は,イシュア上皮帯のような特定の場所に限定されています.
研究 の 目的:
- ラブラドール北部の古代メタセジメント岩の 炭素同位体構成を調べるため
- 初期の生命の証拠があるか調べるためだ
主な方法:
- 総有機炭素含有量の分析
- 炭素同位体の値 (δ13Corgと δ13Ccarb) をグラファイトと炭酸塩で測定する.
- グラファイトの結晶化温度と変形条件の評価
主要な成果:
- 低δ13Corg値は,−28.2まで,いくつかのペリティック岩石で見つかりました.
- グラファイトの結晶化温度が宿主岩の変形温度と一致し,後の汚染を排除します.
- δ13Corg値とメタモルフィックグレードの間の相関は,メタモルフィック以前の生体起源を示唆する.
結論:
- 重要な分割 (最大25‰) が δ13Ccarbと δ13Corgの間にあることは,39億5千万年前に存在した生物の最も古い証拠を示している.
- 発見された生物学的石墨は 初期の生命の詳細な地化学研究を可能にします
- この発見は地球上の初期の生命と 地球外生命の可能性を理解する上で 重要な意味を持つ.
関連する概念動画
Phase Transitions
23.3K
Whether solid, liquid, or gas, a substance's state depends on the order and arrangement of its particles (atoms, molecules, or ions). Particles in the solid pack closely together, generally in a pattern. The particles vibrate about their fixed positions but do not move or squeeze past their neighbors. In liquids, although the particles are closely spaced, they are randomly arranged. The position of the particles are not fixed—that is, they are free to move past their neighbors to...
23.3K
Properties of Transition Metals
30.0K
Transition metals are defined as those elements that have partially filled d orbitals. As shown in Figure 1, the d-block elements in groups 3–12 are transition elements. The f-block elements, also called inner transition metals (the lanthanides and actinides), also meet this criterion because the d orbital is partially occupied before the f orbitals.
30.0K
Cooperative Allosteric Transitions
8.8K
Cooperative allosteric transitions can occur in multimeric proteins, where each subunit of the protein has its own ligand-binding site. When a ligand binds to any of these subunits, it triggers a conformational change that affects the binding sites in the other subunits; this can change the affinity of the other sites for their respective ligands. The ability of the protein to change the shape of its binding site is attributed to the presence of a mix of flexible and stable segments in the...
8.8K
Phase Transitions: Vaporization and Condensation
21.5K
The physical form of a substance changes on changing its temperature. For example, raising the temperature of a liquid causes the liquid to vaporize (convert into vapor). The process is called vaporization—a surface phenomenon. Vaporization occurs when the thermal motion of the molecules overcome the intermolecular forces, and the molecules (at the surface) escape into the gaseous state. When a liquid vaporizes in a closed container, gas molecules cannot escape. As these gas phase molecules...
21.5K
Phase Transitions: Sublimation and Deposition
20.3K
Some solids can transition directly into the gaseous state, bypassing the liquid state, via a process known as sublimation. At room temperature and standard pressure, a piece of dry ice (solid CO2) sublimes, appearing to gradually disappear without ever forming any liquid. Snow and ice sublimate at temperatures below the melting point of water, a slow process that may be accelerated by winds and the reduced atmospheric pressures at high altitudes. When solid iodine is warmed, the solid sublimes...
20.3K
Phase Transitions: Melting and Freezing
15.2K
Heating a crystalline solid increases the average energy of its atoms, molecules, or ions, and the solid gets hotter. At some point, the added energy becomes large enough to partially overcome the forces holding the molecules or ions of the solid in their fixed positions, and the solid begins the process of transitioning to the liquid state or melting. At this point, the temperature of the solid stops rising, despite the continual input of heat, and it remains constant until all of the solid is...
15.2K