对此结果，国际上也有不少研究者提出质疑。一些研究认为，这些观测数据"存在较大噪声干扰，所有 已报告的特征可能只是统计波动"。同时，很多其他分子的模型也能给出类似甚至略好的拟合效果。对 于K2—18b上是否存在水的问题，美国密歇根大学的研究者认为，K2—18b更可能是一颗类似海王星的 气态行星，甚至没有实体表面。此外，实验室天体物理学家在还原性大气中通过化学反应也生成了二甲 基硫醚，研究星际介质的专家提出二甲基硫醚可能来自太空。因此，即使K2—18b上存在二甲基硫醚， 它们或许由非生命过程产生，甚至还可能来自星际介质。 太阳系外是否有生命存在？这个问题一直吸引着人类。宇宙浩渺无垠，恒星之间极为遥远，目前只能依 靠类似JWST的天文望远镜来获取这些行星的光谱。当前比较公认的生命信号探针包括如下情况：如果 发现某颗行星大气中存在明显的氧气或者强烈的紫外吸收（由臭氧层导致）以及甲烷，那么生命就有可 能存在；如果行星光谱存在"红色边缘"或类似的光谱特征，那么这颗星球可能类似于白垩纪年代的地 球，地表几乎全是森林，绿色植物的叶绿素选择性吸收了蓝光和红光，产生了"红色边缘"效应。 科学探索永无止境。为推进相关研究，有不少国 ...

Core Findings - An international team led by astronomer Nikku Madhusudhan from Cambridge University has published findings in the Astrophysical Journal Letters, indicating the discovery of "the strongest evidence yet" for potential life activity in the atmosphere of the exoplanet K2-18b, located approximately 124 light-years from Earth [1] - The atmosphere of K2-18b contains chemical signatures of dimethyl sulfide (DMS) and dimethyl disulfide (DMDS), which on Earth are primarily produced by marine life, suggesting a possible biological origin [1] - This research utilized the James Webb Space Telescope (JWST) to analyze the starlight passing through the planet's atmosphere, revealing the presence of these complex organic molecules, which are more intricate than methane [1] Exoplanet Characteristics - K2-18b is one of the most common types of exoplanets discovered, with a mass approximately 8.6 times that of Earth and a volume about 2.6 times larger, situated within the habitable zone [2] - Previous studies using the Hubble Space Telescope suggested that K2-18b's atmosphere was rich in water vapor, although later analyses indicated that the observed water vapor might actually be methane [2] - The recent study confirmed the presence of methane and carbon dioxide in K2-18b's atmosphere and proposed the existence of dimethyl sulfide for the first time, achieving a detection confidence level of 3.4, which is considered a significant threshold in astronomical observations [2] Scientific Debate - There is skepticism among researchers regarding the findings, with some suggesting that the observational data may be affected by significant noise, and that reported features could be statistical fluctuations [3] - Other models could potentially explain the data with similar or even better fits, raising questions about the existence of water on K2-18b, with some researchers proposing it may resemble a gas giant like Neptune [3] - The possibility that dimethyl sulfide could originate from non-biological processes or interstellar medium has also been raised, indicating that even if detected, these compounds may not necessarily indicate life [3] Future Exploration - Various countries are developing plans to explore exoplanetary life, including China's Tianling Plan and the United States' Habitable Worlds Observatory project, reflecting a growing interest in astrobiology [4] - Advancements in astronomical telescopes, atmospheric modeling, and astrobiology are expected to enhance the understanding of potential life signals in the universe [4]