Back in March of 2010, when the iPhone 3GS running iPhone Software 3.1 was the latest-and-greatest, the default wallpaper image on the iPhone was an image of the Earth. If you are a long-time iPhone user, you probably remember that picture. I wrote about this history of that image, known as Blue Marble, in a post on March 10, 2010. That post still gets a decent amount of traffic today from people searching the Internet for information on the image. I've updated that post over the years as new images of the Earth have become available. For example, yesterday I added links to the cool pictures and video of the moon passing in front of the Earth lit by the Sun, taken from the EPIC camera on the DSCOVR satellite.
I thought about that post on Sunday night, and again last night, when my kids and I looked at the sky both nights and could see Mars. It was fun to see the planet even without the aid of a telescope, and even in a city where we have lots of streetlights and other interference which normally makes it hard to see anything but the Moon at night. As Geoff Gaherty of Space.com explains, Mars has been opposite the Sun in the Earth's sky, making it bright and easy to see with the naked eye. If you haven't seen Mars yet, try again tonight. It's really neat to see another planet so easily.
At first, we had trouble finding Mars. Thus, I launched the Star Walk 2 app ($2.99: 
), a cool app that lets you hold up your iPhone to the night sky; as you move your iPhone around, the app tells you all of the stars, planets, etc. that you are looking at. It turned out that Mars was being blocked from our view by the house across the street. But a few minutes later, Mars rose through the sky and we could see it. Before my son went to bed, he took this picture from his bedroom window using my iPhone, with the Moon in the bottom left and Mars in the top right:
In the iPhone picture taken at very low light, Mars is just a faint white dot. In real life, it was brighter, plus it was orange-red, not white like a star.
Speaking of using your iPhone to explore space, the New York Times recently added a great virtual reality video of Pluto, using images taken with the New Horizons satellite. You need the free NYT VR app to view the video, which I reviewed last year. You can watch the video with any iPhone, but to get the best experience you need to put your iPhone inside of a Google Cardboard device. VR technology is not quite to the point where I can say that watching this video made me feel 100% like I was there, but with headphones on and using Google Cardboard, it was a truly immersive experience, not unlike what you might get at a nice planetarium. My 10 year old son is even more interested in space than I am, and both of us really enjoyed the New York Times presentation on Pluto. Very cool.
One last app that I'll recommend is Luminos ($14.99: ). This astronomy app has an incredible amount of information about space. You can use it to explore the sky, just like Star Walk 2, but you can also get an incredible amount of information on objects in the sky, track satellites, look at Hubble images, simulate being on another planet, etc. It also gives you information about what you can view every day, works on the iPhone and iPad, and even has an Apple Watch app.
Whichever app you use, enjoy learning more about space using your iPhone and iPad!
