Sept 24 - Meet a Famous Star

September 24 Meet a Famous Star by:

Like lights in a dark tunnel, stars in the distant universe become fainter as they're farther away. But Cepheid variable stars reveal their own true distances. Read more.

Meet Delta Cephei, a famous star Delta Cephei is a variable star. You can see it double in brightness on a precise schedule, every 5.36 days. Its brightness changes are tied to its absolute brightness in the distant universe. Learn how to find this star in the night sky, and learn how it - and other stars like it - helped establish the known cosmic distance scale. Read more. Scientists use drones to probe earthly dust devils, with an eye toward Mars Dust devils are common enough are common on Earth, but all over the place on Mars, a desert world. Scientists are chasing dust devils in an Oregon desert, using drones carrying cameras and other instruments to gain new insights. Learn why NASA is funding their efforts. And check out the beautiful image below, of a dust devil on Mars' surface. Read more, and watch an Oregon dust devil swirl. Why Earth has 4 seasons You might assume our planet's changing distance from the sun causes the change in the seasons. That's logical, but not the case. Read more.

EarthSky lunar calendars are back in stock We're guaranteed to sell out, get one while you can! Your support means the world to us and allows us to keep going. Purchase here.

Remember to look for Fomalhaut This chart shows the view southward around 9 p.m. in mid-September, from the Northern Hemisphere. For a larger view, and your specific view, see Stellarium online. In most years, at this time of year, Fomalhaut appears solitary in this region of the evening sky. But, in 2019, Fomalhaut has company. The 2 bright planets Jupiter and Saturn can be found near it. They'll point out Fomalhaut for you.

Tracks of Opportunity rover, with Mars dust devil NASA likely has dust on its mind since the official demise of its Mars Opportunity rover earlier this year. Opportunity - fondly nicknamed Oppy - was built to last 90 days, but spent 15 years exploring Mars, until a planet-wide dust storm hit in June 2018. The rover relied on solar power. Its solar panels are now thought to be blanketed with dust. Engineers at NASA’s Jet Propulsion Laboratory sent more than a thousand commands this past fall and early winter, trying to restore contact with the rover. It didn't work. The rover sits silent on Mars' surface now, in Mars' Perseverance Valley. The image above, from 2016, offers a particularly beautiful and poignant view of the Opportunity rover's tracks on Mars, with a Mars dust devil in the background. Read about scientists on Earth using drones to study dust devils. Submit your photo to EarthSky here! Did a friend forward EarthSkyNews to you? Click here to get your own subscription!

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