Yeah, I can totally see it! How can you miss that? It's right there. Clear eyes, full Earth, can't miss. Wait, really? No of course not. Anyone who tells you that is either a liar or a hawk. Earth looks incredibly tiny up in that Martian sky. Sure, if you squint hard enough and fake it long enough, you'll spot it the dot but it's not unlike looking for dust on a wall.
NASA just posted a picture of the Martian sky and horizon taken by NASA's Curiosity Mars rover and Earth is a shining light in the sky. A really, really, really small shining light in the sky. Here's what it looks like without the cheating label:
That's not a mini dead pixel on your monitor guys, it's Earth. It's us. Below that speck of blue light is actually the Moon too (that I cannot see for the life of me). NASA says:
Researchers used the left eye camera of Curiosity's Mast Camera (Mastcam) to capture this scene about 80 minutes after sunset on the 529th Martian day, or sol, of the rover's work on Mars (Jan. 31, 2014). The image has been processed to remove effects of cosmic rays.
Earth was about 99 million miles away from Mars when Curiosity took that picture above. You can see it in clearer detail here.