概括
早期地球可能比预期的更温暖,原因是大气中的氨. 这种大气中的氨,以百万分之一的比例存在,解决了温度悖论,并暗示了地球和火星未来的气候变化.
科学领域:
- 行星科学 行星科学
- 气候科学 气候科学
- 地质地质地质地质地质地
背景情况:
- 太阳的进化预测地球早期的温度比地质证据表明的要冷.
- 预测和观察到的古代气候之间存在差异,这构成了科学挑战.
研究的目的:
- 解决太阳进化模型与地质气候证据之间的明显矛盾.
- 研究大气组成在早期行星气候中的作用.
主要方法:
- 基于当代的度和大气组成,建模全球平均温度.
- 分析特定大气混合比率的影响,特别是氨.
主要成果:
- 在中间的前坎布里亚大气中,每百万分之几的氨可以解决温度悖论.
- 描述了地球和火星的预测温度进化轨迹.
- 预计大约45亿年后,地球将出现一场失控的温室效应.
结论:
- 氨在早期地球上维持适宜居住的温度方面起到了至关重要的作用.
- 未来的气候预测表明,当地球经历了 runaway 温室效应时,火星是可居住的.
相关概念视频
01:07What is Weather?
Overview
01:16What is Climate?
Climate refers to the prevailing weather conditions in a specific area over an extended period. As the saying goes, “Climate is what you expect. Weather is what you get.” Climate is influenced by geographic factors, such as latitude, terrain, and proximity to bodies of water.
01:50Global Climate Change
Throughout its ~4.5 billion year history, the Earth has experienced periods of warming and cooling. However, the current drastic increase in global temperatures is well outside of the Earth’s cyclic norms, and evidence for human-caused global climate change is compelling. Paleoclimatology, the study of ancient climate conditions, provides ample evidence for human-caused global climate change by comparing recent conditions with those in the past.
02:06Conditions on Early Earth
Around 4 billion years ago, oceans began to condense on earth while volcanic eruptions released nitrogen, carbon dioxide, methane, ammonia, and hydrogen into the primordial atmosphere. However, organisms with the characteristics of life were not initially present on earth. Scientists have used experimentation to determine how organisms evolved that could grow, reproduce, and maintain an internal environment.
02:06Conditions on Early Earth
Around 4 billion years ago, oceans began to condense on earth while volcanic eruptions released nitrogen, carbon dioxide, methane, ammonia, and hydrogen into the primordial atmosphere. However, organisms with the characteristics of life were not initially present on earth. Scientists have used experimentation to determine how organisms evolved that could grow, reproduce, and maintain an internal environment.
01:17Radiation: Applications
The average temperature of Earth is the subject of much current discussion. Earth is in radiative contact with both the Sun and dark space; it receives almost all its energy from the radiation of the Sun and reflects some of it into outer space. Dark space is very cold, about 3 K, so Earth radiates energy into it. For instance, heat transfer occurs from soil and grasses, the rate of which can be so rapid that frost can occur on clear summer evenings, even in warm latitudes.
The average...
The average...