1. A system having at least one processor, storage, and a communication platform connected to a network for identifying candidate queries related to a trending topic, the system comprising: a trending topic identification module that is configured to identify topics trending in one or more real-time content sources, wherein the trending topic identification module comprises: a content segmenting module that is configured to segment received documents from the one or more real-time content sources into words and named entities, a volume calculation module that is configured to calculate a volume for each of a predetermined number of topics by organizing the received documents into two or more portions of documents each defined by a time interval within a historical time period and, for each portion: calculating a probability for every word and named entity within the portion that the respective word or named entity is related to one of the predetermined number of topics, calculating a probability for every document within the portion that the respective document is related to one of the predetermined number of topics, and determining a volume for each of the predetermined number of topics by summing the calculated probabilities that each document is related to the respective topic, and a topic list generation module that is configured to generate a list of trending topics based on the calculated volumes for the predetermined number of topics; and a query recommendation module that is configured to suggest at least one candidate query in response to receiving a user query, wherein the at least one candidate query is obtained by comparing words and named entities of the user query with words and named entities associated with the identified topics.