False image of India during Diwali versus the real thing

The five-day Hindu festival Diwali celebrates the victory of Good over the Evil and Light over Darkness. It also marks the beginning of the Hindu New Year. Lighting lamps, candles, and fireworks are a big part of Diwali. It’s a celebration of light! But can you see those celebratory lights from space? The answer is no. NASA says the extra light produced during Diwali is so subtle that space images don’t show it. This post is about a real satellite image of India during Diwali, versus a false one that’s been circulating on the Internet for a few years, especially around the time of the Diwali festival.

Real satellite image of India, taken at the time of the 2012 Diwali festival. Image acquired November 12, 2012, made possible here via NASA’s Earth Observatory.

This year’s Diwali started on November 11, 2012. The image above – which has been artificially brightened – shows what India looked like from space on the night of November 12, 2012. It’s what India looks like from space on any night, according to NASA.

This image is from a NASA satellite known as Suomi NPP, for National Polar-orbiting Partnership. An instrument carried on this satellite – which detects light in a range of wavelengths from green to near-infrared – acquired this image in a single night. The image has been brightened to make the city lights easier to distinguish.

Most of the bright areas are cities and towns in India, which is home to more than 1.2 billion people and has at least 30 cities with populations over 1 million. Cities in Bangladesh, Nepal, and Pakistan are also visible near the edges of the image.

This image of India has been circulating on the Internet for years. Some claim it shows India during Diwali, but it does not. It’s a real satellite image alright, but it’s composite image, with several different years of lighting combined together. Image via U.S. Defense Meteorological Satellite Program

In contrast, here is the false Diwali image, which has been circulating via the Internet for some years. It doesn’t show what it claims to show; that is, it doesn’t show India on a single night during the Diwali festival.

This image comes from satellite data, too, but not a single satellite on a single night. It’s based on data from U.S. Defense Meteorological Satellite Program (DMSP) satellites, and it’s a color-composite created in 2003 by NOAA scientist Chris Elvidge to highlight population growth over time. In this image, white areas show city lights that were visible prior to 1992, while blue, green, and red shades indicate city lights that became visible in 1992, 1998, and 2003 respectively.

Bottom line: This post contains a real space image of India, taken during the 2012 Diwali festival. The image is shown in contrast to another space image – a composite, put together with data taken over many years – which has circulated in recent years. The composite image does not show India during Diwali. NASA says the extra light so many enjoy during Diwali would not be visible from space.

- EarthSky