Yes, you can learn Data Science online. There are many online courses to learn Data Science but there are very few who provide quality training. To become a Data Scientist, you need to learn Python or R programming, Data Mining, Data Visualization, and Machine Learning techniques and algorithms.
So, ultimately Data Science has a very bright future ahead and if you are a beginner who eagerly wants to learn Data Science then go through this comprehensive Data Science Tutorial.
If you want to dive deep into the field of Data Science then enroll for this Data Science Course by Intellipaat.