Japanese scientists say that the evolution of photosynthesis caused Earth’s oceans to be formerly green, as per a report. The study suggests that the oceans supported only single-celled organisms and featured environments with barren landscapes of grey, brown, and black rocks. Within a period of 1.5 billion years, the slow changes in ocean chemistry could help explain why blue-green algae developed both types of photosynthetic pigments. The color of the planet’s oceans is linked to water chemistry and life influence.

Before Blue: The Green Ocean Era

According to the report, Earth’s oceans were once green. The chemistry and evolution of photosynthesis account for this shift. Discovered throughout the Archean and Paleoproterozoic ages, banded iron formations—which were laid between 3.8 and 1.8 billion years ago—were formed when life was limited to one-celled creatures in the oceans; the continents were desolate gray, brown, and black rock and silt terrain.

Green Seas Sparked Life

The first life using sunlight emerged in the Archean eon, when Earth’s atmosphere and seas lacked gaseous oxygen. These creatures started the “Great Oxidation Event,” a significant ecological turning point permitting advanced life on Earth, using anaerobic photosynthesis. The “bands” of various colours in banded iron formations capture this change with an oscillation between iron deposits devoid of oxygen and red oxidized iron.

The case for green oceans in the Archean eon starts with an observation: waters around the Japanese volcanic island of Iwo Jima have a greenish hue linked to a form of oxidized iron — Fe(III). Blue-green algae thrive in the green waters surrounding the island, and their ancestors evolved alongside other bacteria that use ferrous iron instead of water as the source of electrons for photosynthesis.

Life Changes Ocean Colours

Photosynthetic organisms use pigments (mostly chlorophyll) in their cells to transform carbon dioxide into sugars using the energy of the sun. Genetically engineered modern blue-green algae with phycoerythrobilin (PEB) grow better in green waters, suggesting that pale-green dot worlds viewed from space are excellent candidate planets to harbor early photosynthetic life.

The color of our oceans is linked to water chemistry and the influence of life. Purple oceans could be possible on Earth if the levels of sulfur were high, red oceans could be possible under intense tropical climates, or a type of algae linked to “red tides” could dominate the surface oceans. As the sun ages, changes in the color of our oceans are inevitable, as nothing is permanent at geological timescales.

A new exoplanet has been recently discovered which is reportedly orbiting a nearby star, GI 410. The discovery has been made by a team of international astronomers. The discovery was made as a result of the radial velocity (RV) method. The discovery was made on April 4th, and the planet has been classified as a sub-Neptune exoplanet that comprises a mass of approximately 8.4 Earth masses. Notably, a sub-Neptune is a type of exoplanet that is larger than Earth but smaller than Neptune.

What is the Radial Velocity Method

This technique or method is widely used by astronomers to detect exoplanets. Also known as the RV method, the process here identifies the variations in the velocity of a central star, which has planets orbiting it. The reason behind the variations is caused by a change of direction of the gravitational pull exerted by an exoplanet while orbiting the star. Astronomers have been able to detect over 600 exoplanets”, highlighting the success rate of the novel technique. The details about the discovery were documented in a study published in the pre-print online journal arXiv.

Everything about discovery and astronomers

The team of international astronomers who detected the sub-Neptune exoplanet was under the leadership of Andres Carmony, from the Grenoble Alpes University in France. The device used in the discovery is the SPIRou near-infrared spectropolarimeter at the Canada-France-Hawaii Telescope (CFHT). Furthermore, data from the optical velocimeter SOPHIE supported the observations at the Haute-Provence Observatory.

About the Exoplanet and The Host Star

The new sub-neptune planet has been designated as GI 410 b. It weighs as much as the mass of 8.5 Earths. Making it one of the larger sub-Neptunes to be discovered. Following the detection, it was observed that the radius of the exoplanet, dubbed GI 410 b, remains constant, and it does not pass through its parent star.

On the other hand, the host star, i.e., GI 410 is located at a distance of 39 light years from the planet Earth. The properties of this star are astonishing, as it is half the size of the Sun. Likewise, the temperature of the host star is 3,842 K. Also, GI 410 is one of the youngest “stars” with an age of 480 million years.

Are there more exoplanets?

Post detecting GI 410 b, astronomers have identified tentative signs of evidence of two planetary signals that were detected at 2.99 and 18.7 days. However, further investigations are expected to confirm the existence.

The news of asteroids hitting the earth within seven years has not been proven to be zero. Asteroid 2024 YR4 was in the headlines due to its potential to hit the Earth on 22 December 2032, as reported by NASA’s Center for Near Earth Object Studies (CNEOS) at its Jet Propulsion Laboratory in Southern California. The collision probability peaked at over three percent on February 18, which is the highest recorded for an object of this size. This ignited concerns regarding the damage it could cause if it hit the earth.

Observations and Behavior

A team of astronomers in NASA’s Gemini South Observatory in Chile observed this asteroid at different wavelengths in February for around one and a half months after it was discovered. Asteroid 2024 YR4 swings in the way of Earth every 4 years. However, it will be too distant by next week to be visible by the ground telescope. The James Webb Space Telescope will observe it again later in this month or the next, NASA stated in a post.

The asteroid is nearly 60 metres wide and shaped like a flat disk with a rapid rotation rate of about once every 20 minutes. This finding is unexpected as most of the asteroids’ shapes are like potatoes rather than flat discs, as stated by Bryce Bolin, the lead author of the study. It is more likely to originate in between the Mars and Jupiter asteroid belt, which is rich in silicates.

Assessment of Risk through Science Data

The collision probability of this asteroid is now down to under one percent, and 2024YR4 will no longer hit the Earth by 2032. However, there is a 3.8 percent probability that it could strike the Moon instead, which will not change the moon’s orbit. This incident highlights the need for monitoring the asteroid populations to identify the potential dangers to Earth.

New data collected in the following days lowered the probability to well under 1%, and 2024 YR4 is no longer considered a potential Earth impactor. However, the event underscored the importance of surveying asteroid populations to reveal possible threats to Earth. Sharing scientific data widely allows scientists to determine the risk posed by the near-Earth asteroid population and increases the chances of identifying future asteroid impact hazards in NASA science data.

Scientists help track the asteroids through worldwide observations given to Minor Planet Cenetr. CNEOS and NASA analyze the other potential objects near Earth and evaluate the risks. The planetary defense community recognizes the need of making data products available to everyone, said James Gerbs Bauer, NASA’s planetary Data System‘s principal investigator at the University of Maryland.

Role of Science Data in Future

NASA is working on a new space observatory, NEO Surveyor, the first spacecraft designed to assess the threats of asteroids well in advance. The mission launch date is expected to be in the fall of 2027, and the data received from it will be shared with everyone through NASA archives.

Bauer said that many of the NEOs that threaten the Earth need to be discovered. An asteroid impact might have a low likelihood at that point, but the repercussions could be high, and open science is observant. Thus, sharing the scientific data on a broader scale allows the scientists to define the threat by an NEO and enhance the possibility of discovering the future impact hazards of asteroids in the science data by NASA.