Astronomers find exoplanet with cloud-free atmosphere
London, May 8: Astronomers have found that a planet outside our solar system, which is similar to Saturn in mass and exceeds the size of Jupiter by 20 per cent, has an atmosphere free of clouds.
The hot gas giant, WASP-96b, periodically transits a Sun-like star 980 light years away in the southern constellation Phoenix.
Using the the European Southern Observatory's Very Large Telescope in Chile, the team studied the atmosphere of WASP-96b when the planet passed in front of its host-star.
This enabled the team to measure the decrease of starlight caused by the planet and its atmosphere, and thereby determine the planet's atmospheric composition.
"We've been looking at more than twenty exoplanet transit spectra. WASP-96b is the only exoplanet that appears to be entirely cloud-free and shows such a clear sodium signature, making the planet a benchmark for characterisation," said lead author of the study Nikolay Nikolov from University of Exeter in Britain.
Just like an individual's fingerprints are unique, atoms and molecules have a unique spectral characteristic that can be used to detect their presence in celestial objects.
The spectrum of WASP-96b shows the complete fingerprint of sodium, which can only be observed for an atmosphere free of clouds, according to the study published in the journal Nature.
It has long been predicted that sodium exists in the atmospheres of hot gas-giant exoplanets, and in a cloud-free atmosphere it would produce spectra that are similar in shape to the profile of a camping tent.
"Until now, sodium was revealed either as a very narrow peak or found to be completely missing. This is because the characteristic 'tent-shaped' profile can only be produced deep in the atmosphere of the planet and for most planet clouds appear to get in the way," Nikolov added.
Clouds and hazes are known to exist in some of the hottest and coldest solar system planets and exoplanets.
The presence or absence of clouds and their ability to block light plays an important role in the overall energy budget of planetary atmospheres.
"It is difficult to predict which of these hot atmospheres will have thick clouds. By seeing the full range of possible atmospheres, from very cloudy to nearly cloud-free like WASP-96b, we'll gain a better understanding of what these clouds are made of," explains study co-author Jonathan Fortney, Professor at University of California, Santa Cruz (UCSC), US.
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Grok obscene AI content: X submits response, IT Ministry examining it, say sources
New Delhi (PTI): The IT Ministry is examining the response and submissions made by X following a government directive to crack down on misuse of artificial intelligence chatbot Grok by users for the creation of sexualised and obscene images of women and minors, sources said.
X had been given extended time until Wednesday, 5 PM to submit a detailed Action Taken Report to the ministry, after a stern warning was issued to the Elon Musk-led social media platform over indecent and sexually-explicit content being generated through misuse of AI-based services like 'Grok' and other tools.
Sources told PTI that X has submitted their response, and it is under examination.
The details of X's submission were, however, not immediately known.
On Sunday, X's 'Safety' handle said it takes action against illegal content on its platform, including Child Sexual Abuse Material (CSAM), by removing it, permanently suspending accounts, and working with local governments and law enforcement as necessary.
"Anyone using or prompting Grok to make illegal content will suffer the same consequences as if they upload illegal content," X had said, reiterating the stance taken by Musk on illegal content.
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On January 2, the IT Ministry pulled up X and directed it to immediately remove all vulgar, obscene and unlawful content, especially generated by Grok (X's built-in artificial intelligence interface) or face action under the law.
In the directive on Friday, the ministry asked the US-based social media firm to submit a detailed action taken report (ATR) within 72 hours, spelling out specific technical and organisational measures adopted or proposed in relation to the Grok application; the role and oversight exercised by the Chief Compliance Officer; actions taken against offending content, users and accounts; as well as mechanisms to ensure compliance with the mandatory reporting requirement under Indian laws.
The IT Ministry, in the ultimatum issued, noted that Grok AI, developed by X and integrated on the platform, is being misused by users to create fake accounts to host, generate, publish or share obscene images or videos of women in a derogatory or vulgar manner.
"Importantly, this is not limited to creation of fake accounts but also targets women who host or publish their images or videos, through prompts, image manipulation and synthetic outputs," the ministry said, asserting that such conduct reflects a serious failure of platform-level safeguards and enforcement mechanisms, and amounts to gross misuse of artificial intelligence (AI) technologies in violation of stipulated laws.
The government made it clear to X that compliance with the IT Act and rules is not optional, and that the statutory exemptions under section 79 of the IT Act (which deals with safe harbour and immunity from liability for online intermediaries) are conditional upon strict observance of due diligence obligations.
"Accordingly, you are advised to strictly desist from the hosting, displaying, uploading, publication, transmission, storage, sharing of any content on your platform that is obscene, pornographic, vulgar, indecent, sexually explicit, paedophilic, or otherwise prohibited under any law...," the ministry said.
The government warned X in clear terms that any failure to observe due diligence obligations shall result in the loss of the exemption from liability under section 79 of the IT Act, and that the platform will also be liable for consequential action under other laws, including the IT Act and Bharatiya Nyaya Sanhita.
It asked X to enforce user terms of service and AI usage restrictions, including ensuring strong deterrent measures such as suspension, termination and other enforcement actions against violating users and accounts.
X has also been asked to remove or disable access "without delay" to all content already generated or disseminated in violation of applicable laws, in strict compliance with the timelines prescribed under the IT Rules, 2021, without, as such, vitiating the evidence.
Besides India, the platform has drawn flak in the UK and Malaysia too. Ofcom, the UK's independent communications regulator, in a recent social media post, said: "We are aware of serious concerns raised about a feature on Grok on X that produces undressed images of people and sexualised images of children".
"We have made urgent contact with X and xAI to understand what steps they have taken to comply with their legal duties to protect users in the UK. Based on their response, we will undertake a swift assessment to determine whether there are potential compliance issues that warrant investigation," Ofcom said.
