New Delhi: A groundbreaking NASA experiment—the Double Asteroid Redirection Test (DART) spacecraft sent to the near-Earth asteroid Didymos and its moon Dimorphos in 2022—might have altered the shape and the orbit of Dimorphos after the spacecraft collided with the cosmic object. In a paper published Friday in the journal The Planetary Science, scientists analysed the effect of the experiment as part of which the DART spacecraft was sent to collide with Dimorphos.
This was a planetary defence technique known as ‘kinetic impact’. While Dimorphos itself did not pose a hazard to planet Earth, the experiment was aimed at understanding the potential effect of the kinetic impact technique in averting future hazardous celestial objects away from the Earth.
Scientists found that due to the collision, Dimorphos’s shape changed from oblate (rounded, and slightly flattened on top and bottom) to prolate, which means it became more elongated along one axis. This, according to the scientists, was not in line with the predictions made before the impact.
The impact with DART also changed the nature of Dimorphos’s orbit. This is because debris from DART’s collision with Dimorphos disrupted the gravitational pull of the moon towards Didymos, causing it to end up in a shorter orbit than before.
The paper explained how, in future, the moon may also chaotically tumble around its orbit, but the timeline for this activity is uncertain. The findings are important for the upcoming Hera mission of NASA which will reach the asteroid in 2026 to assess the properties of the two celestial objects. Read more here.
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Rainwater may have played a crucial role in origin of life
Researchers from the University of Chicago and the University of Houston have proposed in a new study that rainwater may have been the key to transform RNA droplets into the first protocells (precursor to cells) on Earth. Published Wednesday in the journal Science Advances, the research said that 3.8 billion years ago, rainwater could have created protective walls around individual RNA droplets, allowing them to evolve into protocells and then life forms.
The study, led by the departments of bioengineering and chemistry at the University of Chicago, said that coacervate droplets—which refer to complex molecules like RNAs, lipids and proteins—are the first signs of cell formation and evolution on Earth.
But since these droplets of RNAs needed to be separate to actually evolve into different biological processes and beings, they needed protective layers around them. The study found that it was rainwater that formed this protective layer and slowed RNA exchange between coacervate droplets, which was essential for differentiation and evolution.
In a lab, the scientists actually recreated the process by using rainwater collected in Houston, while also accounting for the fact that the composition of rainwater now would be different from that of rainwater billions of years ago. The study bridges a significant gap in understanding the origins of life from molecules. Read more here.
What caused Japan’s 1 January 7.5 magnitude earthquake
Geologists have found that the 7.5 magnitude earthquake that struck Japan’s Noto Peninsula on 1 January, 2024, and killed over 280 people began almost simultaneously at two separate points on the tectonic fault. This was a rare “dual-initiation” mechanism that allowed seismic ruptures (fractures on Earth) from two different ends to encircle a resistant fault barrier (places where ruptures slow or stop) at the same time, resulting in an intense earthquake.
The study, published in the journal Science Thursday, looked specifically at the locations where the dual ruptures occurred to understand the phenomenon better.
Led by the University of California, Los Angeles, the study found that the earthquake’s dual epicentres applied pressure from both sides on the fault barrier, which is a location on a tectonic fault (crack in the Earth’s crust) that holds the stress from tectonic plate movement.
Due to the dual force of seismic activity, a violent rupture was triggered in the barrier and led to the massively destructive earthquake. The paper helped explain dual-mechanism earthquakes and could improve seismic risk assessments in future. Read more here.
Mosquitoes can sense our body heat’s infrared radiation
A new study, published Wednesday in the journal Nature, discovered that the mosquito species Aedes aegypti, known for spreading diseases like dengue and Zika virus disease, can detect infrared radiation from human body heat.
Led by researchers from the University of California, Santa Barbara, the study found that infrared radiation significantly helps mosquitoes’ ability to track human hosts. Along with other sensory cues like carbon dioxide exhalation and human odours, mosquitoes can more effectively zero in on potential targets.
The study revealed that specific proteins in the mosquitoes’ antennae help them detect body heat from a distance of up to 70 centimetres, which allows for infrared sensing. The findings of this study could help improve mosquito trap designs and strategies for controlling mosquito populations. Read more here.
(Edited by Radifah Kabir)
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