Scientists Find Elements of Life on an Asteroid

Two chemical compounds necessary to living organisms have been found in material from the asteroid¹ Ryugu.

The Japanese spacecraft Hayabusa2 collected the materials and sent them back to Earth.

The findings from an international group of scientists support the idea that some elements of life arrived on Earth from asteroids² billions of years ago.

Scientists said on Tuesday they discovered uracil and niacin in rocks collected by a Japanese Space Agency aircraft. The samples came from two places on Ryugu in 2019.

Uracil is one of the chemicals present in RNA. RNA is a molecule³ carrying directions for building and operating living organisms. Niacin, also called Vitamin B3 or nicotinic acid, is important for metabolism⁴.

The Ryugu samples traveled 250 million kilometers back to Earth and returned to Earth's surface in a container. The container landed in December 2020 in Australia.

Scientists, for a long time, have aimed to understand the conditions necessary for life on Earth after it formed about 4.5 billion years ago. Bodies like comets, asteroids and meteorites⁵ struck the Earth at that time. The new findings support the theory that those bodies provided the planet with compounds that helped create the first organisms.

Scientists had found organic molecules⁶ in meteorites found on Earth. But it was not clear whether those space rocks had been affected⁷ by Earth's environment after landing.

"We suspect (uracil and niacin) had a role in...evolution on Earth and possibly for the emergence⁸ of first life," said astrochemist Yasuhiro Oba of Hokkaido University in Japan. An astrochemist studies chemistry in places other than Earth. He is lead writer of the research published in Nature Communications.

RNA is short for ribonucleic acid. Uracil is necessary to form RNA, a group of molecules present in all living cells and very important for the activity of genes⁹. RNA is similar to DNA¹⁰, the molecules that carry an organism's genetic¹¹ instructions.

Niacin is important for metabolism and can help produce the "energy" that powers living organisms.

Oba said uracil and niacin were found at both landing sites on Ryugu. The asteroid is about 900 meters in diameter and is considered a near-Earth asteroid. The amounts of the compounds were higher at one of the places than the other on the asteroid.

Asteroids are rocky space bodies that formed in the early period of the solar system. The researchers suggest that the organic compounds found on Ryugu may have been formed with the help of chemical reactions caused by starlight in icy materials in space.

Words in This Story

asteroid — n. a large group of small bodies that orbit the sun

metabolism — n. the process in living cells of producing energy and new substances

role — n. the part that something plays in a process or activity

evolution — n. the theory that changes in plants and animals happen because of natural processes over long periods of time

emergence — n. the act of becoming seen or coming into existence

instructions –n. (often pl.) a set of statements, letters or codes that enable something to be done

1 asteroid   

n.小行星；海盘车(动物)

参考例句：

• Astronomers have yet to witness an asteroid impact with another planet.天文学家还没有目击过小行星撞击其它行星。
• It's very unlikely that an asteroid will crash into Earth but the danger exists.小行星撞地球的可能性很小，但这样的危险还是存在的。

2 asteroids   

n.小行星( asteroid的名词复数 )；海盘车，海星

参考例句：

• Asteroids,also known as "minor planets",are numerous in the outer space. 小行星，亦称为“小型行星”，在外太空中不计其数。
• Most stars probably have their quota of planets, meteorids, comets, and asteroids. 多数恒星也许还拥有若干行星、流星、彗星和小行星。

3 molecule   

n.分子，克分子

参考例句：

• A molecule of water is made up of two atoms of hygrogen and one atom of oxygen.一个水分子是由P妈̬f婘̬ 妈̬成的。
• This gives us the structural formula of the molecule.这种方式给出了分子的结构式。

4 metabolism   

n.新陈代谢

参考例句：

• After years of dieting,Carol's metabolism was completely out of whack.经过数年的节食，卡罗尔的新陈代谢完全紊乱了。
• All living matter undergoes a process of metabolism.生物都有新陈代谢。

5 meteorites   

n.陨星( meteorite的名词复数 )

参考例句：

• Small meteorites have left impact craters all over the planet's surface. 这个行星的表面布满了小块陨石留下的撞击坑。 来自《简明英汉词典》
• One theory about the existence of extraterrestrial life rests on the presence of carbon compounds in meteorites. 地球外存在生命的理论是基于陨星上存在碳化合物质这一事实的。 来自《简明英汉词典》

6 molecules   

分子( molecule的名词复数 )

参考例句：

• The structure of molecules can be seen under an electron microscope. 分子的结构可在电子显微镜下观察到。
• Inside the reactor the large molecules are cracked into smaller molecules. 在反应堆里，大分子裂变为小分子。

7 affected   

adj.不自然的，假装的

参考例句：

• She showed an affected interest in our subject.她假装对我们的课题感到兴趣。
• His manners are affected.他的态度不自然。

8 emergence   

n.浮现，显现，出现，（植物）突出体

参考例句：

• The last decade saw the emergence of a dynamic economy.最近10年见证了经济增长的姿态。
• Language emerges and develops with the emergence and development of society.语言是随着社会的产生而产生，随着社会的发展而发展的。

9 genes   

n.基因( gene的名词复数 )

参考例句：

• You have good genes from your parents, so you should live a long time. 你从父母那儿获得优良的基因，所以能够活得很长。 来自《简明英汉词典》
• Differences will help to reveal the functions of the genes. 它们间的差异将会帮助我们揭开基因多种功能。 来自英汉非文学 - 生命科学 - 生物技术的世纪

10 DNA   

(缩)deoxyribonucleic acid 脱氧核糖核酸

参考例句：

• DNA is stored in the nucleus of a cell.脱氧核糖核酸储存于细胞的细胞核里。
• Gene mutations are alterations in the DNA code.基因突变是指DNA密码的改变。

11 genetic   

adj.遗传的，遗传学的

参考例句：

• It's very difficult to treat genetic diseases.遗传性疾病治疗起来很困难。
• Each daughter cell can receive a full complement of the genetic information.每个子细胞可以收到遗传信息的一个完全补偿物。