In this week's Science Saturday, we look at science news ranging from massive galaxies to artificial intelligence (AI).

Massive galaxies

Astronomers have found six huge galaxies, dating back 600 million years. Most galaxies at that time were still small and slowly grow over time. But each of the new galaxies weighs billions of times more than the sun and have fast-tracked to maturity. The observations are among the first data that comes from the Webb telescope, from NASA and the European Space Agency. Experts say the findings call the whole picture of early galaxy formation into question.

Contamination fears

Pacific island nations are urging Japan to delay the release of Fukushima waste water. Japan says water from the crippled Fukushima nuclear power plant could be released into the sea "around this spring or summer." But Pacific island nations say the move will contaminate fishing grounds that island economies rely on, and where up to half of the world's tuna is sourced. In March 2011, an earthquake and tsunami resulted in a nuclear disaster at the Fukushima Daiichi nuclear power plant.

HIV therapy

A stem cell transplant has cured a man of HIV. The 53-year-old German man was diagnosed with HIV in 2008 and is the third person to be cured of HIV using this treatment. Like the other two patients, the German man had the transplant to treat a blood disorder, in his case it was leukaemia, which had developed alongside the HIV infection. More than 10 years after the transplant and four years after ending his HIV therapy, he is in good health.

Domestic robots

About 39 percent of domestic work can become automated within a decade. The data was collected from 65 AI experts. They predict grocery shopping is likely to see the most automation, while caring for the young or old is the least likely to be impacted by AI. They suggest that such technology should be subsidized for certain groups like the elderly, as it's expensive. They are calling on policymakers to consider the social and economic implications of unpaid work and evaluate the potential benefits and costs of new technologies.