What is the cosmic microwave background radiation?
The cosmic microwave background radiation, or CMB, is a faint glow of electromagnetic radiation filling
What is dark matter and why can’t we see it?
If you’ve ever gazed up at the night sky, you’re seeing only a small fraction
What is dark matter and dark energy?
categories: Physics We often hear about dark matter and dark energy as two of the biggest
What Is Dark Matter? The Evidence, The Leading Ideas, and What We Still Don’t Know
Dark matter is unseen mass inferred from gravity. Learn the key evidence (galaxy rotation, lensing, clusters), what it might be, and why it’s hard to detect.